Tell us what you know about the theory of evolution without using anything but your own brain.

[Skald the Rhymer]

I thought about opening this thread in IMHO or MPSIMS, but if the thread gets any legs at all I'm sure a discussion will break out so I decided not to bother. I opened the thread here rather than in GQ because my primary interest is seeing what people hereabouts know about evolutionary theory. A couple of comments:


For obvious reasons, please don't go to talk.origins, Wikipedia, or any other reference sites until you have made your first response to the thread. In fact, if you could refrain from links and citations in your first response, that would be great.
Please also make your first response in the thread without reading other responses to the OP.
Once you're past your first entry, cite (and call for cites) to your heart's consent. Likewise, you may point out errors, misconceptions, incomplete ideas, and misleading statements in previous posts. Just try to leave your swords in their scabbards, revolvers in their holsters, and axes in whatever you store your axes in.


Go.

[AHunter3]

OK, here is what I think I know about evolution.

a) All physiological structures are coded for in DNA, and all DNA is inherited directly from one's parents via meiosis (whereby you get a haploid set from each parent, adding up to a full set of chromosomes of your own). Hmm that's not quite accurate; it's true for sexually dimorphic species but... OK, non-sexually-dimorphic life forms inherit all of their DNA from their (one) parent organism.

b) However, mutations occur spontaneously, thereby allowing for organisms to end up with DNA strings that were not truly inherited at all. These in turn may not manifest themselves in any appreciable manner until several generations later.

c) All characteristics that are physiological, or are epiphenomenae of physiological structures, have a potential impact on fitness for survival. Some of these characteristics may manifest at the individual level (the tendency of an individual to run faster etc), some may manifest interactionally and yet contribute to the likelihood of individual survival (the tendency of a group to take care of young individuals, etc). Individuals less geared towards survival are statistically less likely to survive long enough to pass on their own DNA via reproduction.

d) Over time, DNA that thrives is that which was better geared towards survival as described in c) above; DNA that disappears from the gene pool is that which keyed for traits that made individual survival less likely as described in c) above.

[Strinka]

It's pretty simple. When an organism reproduces, it's offspring aren't exactly the same as it. Some differences (in a given environment) are advantageous, some are disadvantageous. Advantageous mutations are more likely to last, and get passed on to further generations.

[Skald the Rhymer]

Starting off ...

The theory of evolution (henceforth TOE) is the dominant biological model for the existence and diversity of species on planet Earth. Its primary components are the notions of common descent, inheritance and modification, and survival of the fittest.

Common descent means that all life forms currently in existence share a single primordial ancestor. Over the eons since life began, the lineage of that ancestor has spread, changed, and branched out. The more recently a given pair of species separated, the more closely they are considered to be related and the more similar they are likely to be. Nevertheless, humans, aardvarks, starfish, planarians, and bacteria all descend from the same stock.

Inheritance and modification means that the physical features of an organism derive from its ancestors--most immediately its parents or parents. Such traits are transmitted through DNA, a self-replicating molecule present in the genes of all living creatures. Because DNA does not always replicate perfectly, over time more and more variations are created in a population.

Survival of the fittest means that organisms in a given species and population are obliged to compete for the opportunity to reproduce; this is because of the scarcity of resources, and often because of less-than-infinite breeding opportunities. Because of the differences in DNA in a given population, no two organisms are identical (except for identical twins) and thus bring different advantages and weaknesses to the table. If a given organism possess a feature that makes breeding more likely in given conditions, it will pass on its genes in greater number than other individuals. Likewise, a given organism may possess features that inhibit its chances to breed, which will result in said features becoming less prevalent over time. Because conditions in the environment change, features that are useful at one point may because liabilities later, and vice versa.

Evolution is not telelogical; there is no ultimate aim or purpse to it. Humans are not more highly evolved than chimpanzees, parakeets, or even parameciums; they are just differently evolved.

The TOE is silent on the existence of God or gods. It is conceivable that no deities exists and that that evolution alone accounts for the diversity species; it is also conceivable that supernatural agents use evolution to cause species to grow, flower, separate, and die out. The TOE works either way.

[Rumor_Watkins]

environmental factors cause certain traits to have comparative advantages over other traits in a given population - over time, the traits with such competitive advantages become common and become a characteristic of the population overall.

[Cort]

Populations adapt to suit their environments. Characteristics which increase a creature's chances of reaching breeding age are obviously more likely to be passed on to the offspring. Over generations, these beneficial characteristics become the norm. On top of this, environmental pressures can divide populations and they can subsequently go their separate ways, happily breeding and adapting like rabbits (especially if they are rabbits :) ), until members of population A can't breed with members of population B anymore. This is called Speciation. That's basically it.

[Alessan]

Various variations and mutations appear in the DNA of all organisms. When a certain such variation or mutation has a positive effect on the survival of a certain population of creatures in a certain place and time, it can become more common in that population. As a result, after many generations, the DNA of that population can be altered significantly from its original form. The process is lengthy, imprecise and essentially directionless, with many "dead ends" along the way.

How'd I do?

[Skald the Rhymer]

Populations adapt to suit their environments. Characteristics which increase a creature's chances of reaching breeding age are obviously more likely to be passed on to the offspring. Over generations, these beneficial characteristics become the norm. On top of this, environmental pressures can divide populations and they can subsequently go their separate ways, happily breeding and adapting like rabbits (especially if they are rabbits :) ), until members of population A can't breed with members of population B anymore. This is called Speciation. That's basically it.

I have an issue with the bolded sentence; it needs additional qualification. I can easily imagine the existence of traits which help an individual reach breeding age but which makes it less likely that said individuals will reproduce. Also, I think you need the word heritable at the beginning of the sentence.

Anybody smarter than me think otherwise? (Because I know there's dozens of Dopers smarter than me, though few prettier.)

[Mosier]

Biogenesis is life that occurs without "parents" or previous ancestors, basically the "first" life. At least one event of biogenesis happened on earth, which all living things are descended from.

Each generation has a chance to be slightly different than previous generations, causing variations. Over time, these differences cause species to branch out and create new species. The closer your species' branch is to another species' branch, the more closely related you are. Humans are closely related to apes. Apes and humans are more closely related to dogs than fish. Apes, humans, dogs, and fish are all more closely related to each other than they are to plants, but if you go back far enough every organism on the planet has a common ancestor.

[El_Kabong]

1. Evolution = things change over time. Abundant evidence exists that evolution has occurred at all levels, from the universe as a system to individual lifeforms. The geologic record shows that composition of the atmosphere and surface features of Earth have changed considerably over time. There is fossil evidence of numerous lifeforms that were once widespread but now are extinct or greatly changed in form from that of their ancestors.

2. An aspect of evolutionary theory that seems to be a point of contention for many is the theory of natural selection, which, among other things, posits that lifeforms tend to evolve based on a combination of mutations at the cellular level and environmental pressures, into other lifeforms that nevertheless share a common ancestor. Considerable evidence exists for a process of evolution through natural selection, although not every link in the evolutionary chain has, or can be, identified.

How'd I do?

[jjimm]

I have read the OP then hit the "end" button to avoid reading anyone else's responses. Apologies for inaccuracies, and hoping for pointers where I have stuff wrong.

So, we have a planet that, several billions of years ago, was chugging along with water and geysers and volcanic activity. Due to the circumstances, various molecules are being formed and destroyed on a very regular basis. Some of these, amino acids, are robust molecules, and in certain reactions they bond with each other and form proteins. A few of these proteins have self-replicating qualities, and are in the circumstances to do just that. This is abiogenesis, but not necessarily life.

[I am very ropy about the next part...]

After a few million squillion years, these self-replicating proteins have become so complex that they have bonded together in myriad reactions and eventually some of them have become ribonucleic acid (RNA) and deoxyriobnucleic acid (DNA), which are supremely robust self-replicating molecules, that also contains complex information about that self-replication. A single unit of informational coding on the double-helix of the DNA molecule is known as a gene.

Through the process of self-replication, mutation, and "survival of the fittest", various forms of DNA begin to appear in extremely complex forms - the DNA allows complex structures to arise around itself, and we see for the first time things that resemble cells: simple bacterium-like lifeforms that have an outer protein shell, and an inner nucleus that contains the important DNA. Other protein molecules arise within these structure to maintain it.

[At this point in my explanation, I myself am starting to believe in Intelligent Design...]

From the start these unicellular "lifeforms", which, due to mutation, can be very different depending on their circumstances, interact and compete. Many die out, but some of them also end up in symbiotic relationships with their peers. In particular, one RNA-based structure becomes incorporated into a larger DNA-based structure, and this symbiosis proves extremely productive: the RNA-based "bacterium" becomes what we now know as the mitochondrium, a structure which coexists within the nucleus of a cell, and provides proteins that service and maintain the instructions of the DNA.

Over billions of years, thanks to environment, mutation and selection, unicellular organisms become more and more complex, for example, some growing scillia (hairs) for propulsion, light-sensitive structures, simple food-sensing parts. Meanwhile the symbiosis between the various unicellular organisms continues, and gradually colonies of these cells become indistinguishable from multicellular organisms.

At this time, all evolution was in the sea, and these organisms, with various appendages and tools, created from mutation and selection, spread throughout the seas. Each organism, over generations, adapts and changes successfully, but the majority die out. At some point [and I have no fucking idea when, or if I'm even correct], the method of replication alters: where cellular organisms replicated by splitting, some multicellular organisms developed two different kinds of the same organism, bearing different DNA codes (known as "chromosomes"). The chance for genetic alteration and mutation was greatly increased by this shift, leading to what we know as sexual reproduction, and organisms that developed this tended up adapt faster than asexual reproducers.

Meanwhile, for many organisms, the amount of information - the genes - contained on the self-replicating DNA molecules increased and increased, and the complexity of the lifeforms increased too. Gradually, these creatures developed structures that allowed them to reach to all parts of the oceans, and eventually they evolved structures that allowed them to leave the oceans.

Through the same process, multitudes of what we know as plants, and what we know as animals, flourished in the oceans and on land, continually mutating, colonising, working in symbiosis, and adapting. Almost all were still based on the DNA/cellular/genetic structure Some were cold-blooded, some warm-blooded, some had scales, some had feathers, some had leaves and bark. Millions of species continued adapting, splitting from each other based on circumstance, mutation, adaptation, extinction, until the moment we now arrive at.

Eventually, life conquered the earth.

[orcenio]

1. It's the process where organisms, in a species, become more adapted to their environment through genetic changes.

2. It is driven by Natural Selection:
a) Natural selection is the reproductively positive/negative selection of organisms who have, generically determined, beneficial/ill-adapted traits.

3. Genetic recombination, mutations, and diversity all play a role in keeping:
a) the gene pool fresh bubbling
b) individual organisms ready to adapt to new environments.

I only have these three main points, jeez, I wish I had something else to throw at ya.

[orcenio]

Oh yes, a small addition...

Apparently evolution doesn't even require organisms to work. It only needs things which exhibit heredity and a changing environment to drive selection.

[TimeWinder]

1. Offspring are mostly a (comingled) copy of their parent(s)'s attributes
2. But there are occasional very small changes.
3. Some changes increase or decrease an organism's ability to reproduce or survive to reproduce in a given environment.
4. By (1), (2), and (3), changes which increase an organisms ability to reproduce in a given environment tend to be represented in more and more members of the species over time. Changes which decrease an organisms ability to reproduce tend die out (but may recur as mutation again). The speed by which an attribute takes over or dies out depends on how much it alters reproductive odds.

5. Environments are different, and they sometimes change.
6. By (4) and (5), organisms (even of the same species) that develop in different conditions will carry different attributes.

7. Generally, organisms can interbreed with organisms with similar attributes. This is a common (but not the only) definition of "species."
8. But there are attributes which are incompatible with interbreeding.
9. By (6), (7), and (8), organisms which develop in different conditions over a sufficient period of time to develop breeding incompatibilities are commonly considered to have become separate species.

10. Trivial (CS-101 homework level) computer simulations of this process demonstrate that even very small increased/decreased reproductive success rates of a mutation will either die out or come to dominate a population in a much shorter time than most people realize (a few thousand generations is more than enough).

11. No crocoducks are harmed in this process. No "goal" exists for the process beyond better adaptation to the environment of the moment. Nothing is ever in a "half form."

12. Demonstration of an irreproducably complex attribute which could not have evolved in a small number of coincident mutations would be a devastating argument against evolutionary theory. But
12a. There haven't been any found yet, and the theory of course predicts none will be.
12b. It wouldn't make Creationism or Intelligent Design correct even if there were
12c. Opponents of evolution aren't listening when people tell them that they have to come up with something more than just the ear or the eye, which have been shown not only not to be irreproducably complex, but that each stage of the evolution of these organs is still present in modern nature.

13. Standard evolutionary/natural selection processes can apply to non-living things, so long as reproduction and selection are present, and there's nothing special about "living" things besides their life.

14. Certain relatively simple chemical compounds are cable of self reproduction (in the simplest cases, merely by growing too large and breaking).

15. There were (and are) a lot of random chemical compounds floating around in the primordial and current ecosystems.

16. (13), (14), and (15) give a plausible explanation for abiogenesis (the transition from lifelessness to life). Most other proposed non-scientific theories fail the induction principle (they require spontaneous generation of a complex system in order to explain the spontaneous generation of complex systems), and hence are obviously invalid from a logical standpoint.

17. A significant percentage of the people on earth believe in the non-scientific explanation anyway.

18. The number of people who believe in a fact has no bearing on its truth or falsehood.

[Silverstreak Wonder]

Well I think of evolution as saying if you wait long enough all combinations of atoms will happen thus there is no creator or plan. Some of these become alive, somehow, and reproduce right away, somehow.

I don't believe much of it because if I go for a walk in the woods and see a squirrel atop a junk TV set I'd have to believe they BOTH just randomly formed there then, they are so adamant there is no maker of anything. When I believe the 1957 Chevy cars just spontaneously formed in 1957, then I will believe the squirrel in the park did as well. I actually have less problem with that occasionally something could randomly form, but that it is alive and that it just happened to be able to reproduce, now there is the problem.

The other problem is it fails to explain LIFE or why scientists cannot give life to something. They know every element in a cell yet cannot build a living one, why? They could even make it larger so easier to work with, but they seem to make not a thing alive while claiming it just formed randomly in a pond. Well, then go make us some of those. I notice all evolutionists never talk about why they cannot create life, and it is supposed to be easy once you set up the right materials. If they cannot even BEGIN their process, why would I want to believe the rest of it?

[garygnu]

First off, evolution doesn't deal with the origin of life, only with how it changes over time.

Charles Darwin published On the Origin of Species by Means of Natural Selection 150 years ago after years of study and thought. The basic idea is that changes in living things are passed down to descendants, and that changes increasing an organism's chances of survival and reproduction are more likely to be passed down than changes that don't.

Gregor Medel's work on heredity showed how these changes are passed down from generation to generation. The later discovery of DNA showed the precise conduit for the changes. The genes contained within DNA can mutate. Even though most mutations result in changes that are selected against, some produce a benefit. Some mutations are neither beneficial or harmful, and are still passed down to descendants. Still other mutations are harmful, but survive through enough generations to be altered further into a beneficial mutation.
The ingenuity of the process is astounding and fascinating.

Initially this process was thought to take place gradually or long stretches of time. However, a newer theory called "punctuated equilibrium" suggests long stretches of little or no change in species interrupted by shorter (but still long by human standards) periods of great change. These upheavals usually coincide with changes in the environment ranging from meteor impacts and extinction events to bodies of water and land masses becoming isolated.

Every time new information is discovered relating to life, the theory of evolution has been validated. I can't think of a time when the result of a test hasn't been predicted to some degree by what evolution would expect. Like any other part of science, evolution is subject to alterations based on future research, and we don't know everything and we never will.

[Silverstreak Wonder]

Yes I will also agree many things can change over time and that they had to be so designed to be able to live on a planet with seasons of the year, and the much longer solar seasons that bring ice ages and such. I believe in the big bang, and the 14 billion years and all that, in fact nothing in scripture says otherwise.

I still remember the 1950's going to the university where an evolutionist blasted how silly and stupid was the idea everything started all at once in a big burst of light and then gasses and water and such with no form and void formed what we have now, complete silliness. He then told us about the real answer, the steady state theory. Everything just always was. Well that covers it, and he said no need to look any further. I wonder what he would say today about the big bang, which sounds an awful lot like scripture?

But the forming of life DOES form the basis for the theory of evolution today, it cannot be left out unless you stick in a creator and they SURE are not going to do that. So, let them build a living cell and they can use any elements in the whole table, make it any size, but they must be able to put life in it without bringing life from something else to it. It must feed, grow, expel wastes, reproduce, and do everything a simple cell does. Till they do the whole theory is unproven.

I do agree with post 3 that changes can happen as generations go by, but who says it is random, it may be programmed into genetics to change this way or that if it gets cooler or dryer for instance, I doubt many changes are mutations at all, maybe a very few. But build me stuff that is alive first, out of just the elements on earth, then we can talk further about the rest of the theory.

[DanBlather]

Well I think of evolution as saying if you wait long enough all combinations of atoms will happen thus there is no creator or plan. Some of these become alive, somehow, and reproduce right away, somehow.

I don't believe much of it because if I go for a walk in the woods and see a squirrel atop a junk TV set I'd have to believe they BOTH just randomly formed there then, they are so adamant there is no maker of anything. When I believe the 1957 Chevy cars just spontaneously formed in 1957, then I will believe the squirrel in the park did as well. I actually have less problem with that occasionally something could randomly form, but that it is alive and that it just happened to be able to reproduce, now there is the problem.

The other problem is it fails to explain LIFE or why scientists cannot give life to something. They know every element in a cell yet cannot build a living one, why? They could even make it larger so easier to work with, but they seem to make not a thing alive while claiming it just formed randomly in a pond. Well, then go make us some of those. I notice all evolutionists never talk about why they cannot create life, and it is supposed to be easy once you set up the right materials. If they cannot even BEGIN their process, why would I want to believe the rest of it?I also don't believe in anything scientists can't build in a lab. As far as I know there is no sun. I'm not so sure about gravity either. They can "demonstrate" it, but they can't "create" it. I'm pretty good with light, though. Even back in the early times they could make light using fire (except during the Great Flood when things were kinda soggy for a while). I get most of my science news from Fox because they use shorter words than shows like Nova on PBS.

[Half Man Half Wit]

Evolution is the necessary outcome of information copying itself imperfectly, but nevertheless with high fidelity, at a rate depending on external factors providing finite resources for copy-creation.

[Noone Special]

OK -- going by the rules and having read nothing but the OP:

In a real nutshell....

1. Random mutations.
2. Natural Selection ("survival of the fittest.")
3. LOTS of time for stuff to happen.

Really, that's pretty much all there is to it -- all the rest is, in a sense, commentary. E.g., I know some or a lot about Punctuated Equilibrium, Gene Diversity, Isolated Populations and why they change, Genetic Similarity, why we aren't "descended" from chimps, or even from monkeys... etc.... But in the end it pretty much boils down to the three points above.

I've included "time" in the basic points, because a lot of otherwise intelligent and open minded people just can't wrap their minds around just how much change can accumulate over time, in tiny, invisible increments.

[Noone Special]

Having read the responses above, I think the main thing I missed (mostly because it seems so absolutely obvious to me that I didn't mention it) is that there is no inherent meaning or goal.
Also, maybe, that evolution is not to be confused with abiogenesis.

[GoodOmens]

It's a lie promoted by the Great Deciever Satan to cast our beliefs away from the truth that God created all living things in their current form only a few thous...

Oh, hell, I can't even type that with a straight face.

[lee]

Evolution is the idea that all life we see today is the result of tiny changes in each generation rather than one act of creation which made life as we see it fully formed. Classically this is called the tree of life with the thought that the first life was simpler and grew more complex as the changes piled one on top of another, and branched as part of a generation grew different from others until speciation occurred.

We know know that is not quite the way it works as genes can be passed laterally between even diverse species as well as with reproduction. The tree of life also leads to the misunderstanding that more visibly complex creatures are somehow more evolved (and therefore somehow better) than less visibly complex, as if the bacteria today have not been evolving all the while. If anything is more evolved than anything else, we could call that which has the shortest generations more evolved than species which take longer to reproduce.

Another idea that has been popular is that the more genes in a genome, the more evolved the creature. To our chagrin, we found we do not have as many genes as rice or many other organisms which don't do things like talk about the theory of evolution.


One can look at DNA and get an idea of the history of a species. Past changes leave their mark. In some cases similar genes appear different places in the genetic code and serve as a type of copy protection. Genes which no longer active for the most part don't get the benefit of this and can change without effecting a change on the organism.

Also, not all genes present are expressed in each generation and we don't understand well how and why that works. Another interesting recent change to our understanding is that environment can play a role in what genes get expressed, and changes to it during the development of one generation can but not necessarily do affect successive generatons even when the conditions revert. This was first noticed in a frog which developed different traits if it grew in dry or wet conditions. The changes were kept in their offspring, even if the conditions which triggered the change were not present during the development of the offspring.


The basics of evolution, that successive generations of an organism show changes to their genome, have been demonstrated in the laboratory in various ways. Another idea that goes along with that is that each generation is more adapted to its environment than the previous one. This leads to the value judgment that newer is better, or at least fitter. This leads to the idea that what we see today in expressed genes has purpose, that any change which was kept is superior to one that was discarded. We can demonstrate that some changes that occur do have benefit for an organism. One scientist did an experiment, watching generations of some bacteria and recording the changes, and preserving samples along the way. At some point the bacteria population expanded greatly and on investigation, the bacteria had obtained the ability to use the medium he was keeping it in as food. On investigation it was found that the change was the result of changes to multiple genes, which occurred at different generations. It was only after the final change was made than any of the changes had any observable use, but nonetheless, the other changes were kept.

Ok, I have more I could say, but I need to get out the door. This all was from the top of my head. Most of the ideas and examples can be found in various articles of New Scientist and Science News, but I did not open them back up to type this post.

[Sandwich]

Many living things reproduce sexually.
The offspring are not identical to either of the parents.
Occassionally an offspring will have a signficantly different trait from either of its parents - a mutation.
Sometimes such traits are hereditable (a word I just made up?) - if the offspring itself reproduces there is a good chance its offspring will have the same new trait.
If such a trait confers a reproductive advantage then it is likely that it will become more common in the population (and vice versa).
Repeat for hundreds of generations in a range of different environments.
Useful variants prosper to the extent that the species eventually diverge.
Over aeons it looks like the animals are deliberately adapting themselves to exploit their surroundings. They're not, it's a product of chance, but it's not arbitrarily random. Valuable modifications are strongly favoured and this creates patterns of successful adaptation.

[Mangetout]

Variety exists in organisms (between individuals and between populations), for lots of reasons, including genetic ones.

Variations that are genetic may be passed on to offspring

In any given environmental context, some variations may confer various advantages or disadvantages to their owner (or less frequently, the group in general).

Some of those advantages and disadvantages may impact on reproductive success

So variations that confer reproductive advantage within a given context tend to be passed on to offspring (and therefore accumulated/preserved); variations that confer reproductive disadvantage, not so much.

Because they are dependent on differential success within a given context, the preserved variations tend to accumulate in such a way as to 'fit' that context (not necessarily best concievable fit though, unless the process as a whole happens to stumble upon it).

A change to the environmental context (or introduction into/invasion of a new one) may introduce new or different pressures on the organisms in it - if they are able to survive at all in the new conditions, the process will continue to stumble toward a new 'fit'. Otherwise, the organisms may just die out.

Resources in many environmental contexts are usually limited, therefore, the overwhelming success of a group with a fantastic 'fit' may still prevail over another whose fit is merely adequate.

Edited to add: There is nothing (save for viability) to constrain the indefinite accumulation of variations - that is, individual B is the already-modified offspring of its parent A and its offspring C will be a modified version of B, not A

[Smeghead]

Speaking as a grad student in a population genetics lab...I don't have the time.

[John Mace]

Someone once posted this in a thread about evolution:

Try everything.
Kill whatever doesn't work.
Repeat.

[Silverstreak Wonder]

The problem with the random mutation idea are several, there would be so many bad changes most would die out, and worst of all, the same bad changes would occur over and over because nothing is keeping track. Instead we see animals getting more adjusted to their environment.

Speaking of mutations, sure there are some, cancer, isn't that a mutation, uncontrolled cell growth. Just what an evolutionist wants to see, but the problem is when has cancer ever grown a new organ, or anything beneficial?

It is just that sort of random error you all say makes these new organs and such and then the stronger of those survive, OK, where are the beneficial changes from cancer then? Why aren't we seeing new organs and tissues develop in animals randomly all the time and some better than before?

We are also supposed to always adjust to stuff that lasts a long long time, so why can't we look at the sun? It has been at about same brightness billions of years. Why also don't we love to feed on the most common thing that could sustain us, grass and leaves? Wouldn't this selection process of who survives favor those who can eat the most common things available?

Above all how would we have evolved to eat cooked food, with none of that to be found in the environment and to only like 70 degree temperatures when no where on earth has that regularly? Then look at our lousy feet, we can't even walk in the jungle or run from prey in bare feet, yet we are at the TOP of the evolution process?

Where is our night vision and blood hound nose and wide temperature range if we are at the top? Why do we burn up with sunburn with only a few hours exposure, animals don't, even those with little fur, how is our skin an improvement and where would we develop such skin when the sun is everywhere? Lots and lots of holes in that evolution theory.

[Noone Special]

Speaking of mutations, sure there are some, cancer, isn't that a mutation, uncontrolled cell growth. Just what an evolutionist wants to see, but the problem is when has cancer ever grown a new organ, or anything beneficial?

It is just that sort of random error you all say makes these new organs and such and then the stronger of those survive, OK, where are the beneficial changes from cancer then? Why aren't we seeing new organs and tissues develop in animals randomly all the time and some better than before? Cancer is not what we're calling a "mutation" here. A mutation is a change in an individual organism's genetic code that is propagated to its offspring (i.e., either a change that occurs really early on in embryonic life, or one that affects the sex cells)

We are also supposed to always adjust to stuff that lasts a long long time, so why can't we look at the sun? It has been at about same brightness billions of years. Why also don't we love to feed on the most common thing that could sustain us, grass and leaves? Wouldn't this selection process of who survives favor those who can eat the most common things available?

Above all how would we have evolved to eat cooked food, with none of that to be found in the environment and to only like 70 degree temperatures when no where on earth has that regularly? Then look at our lousy feet, we can't even walk in the jungle or run from prey in bare feet, yet we are at the TOP of the evolution process?

Where is our night vision and blood hound nose and wide temperature range if we are at the top? Why do we burn up with sunburn with only a few hours exposure, animals don't, even those with little fur, how is our skin an improvement and where would we develop such skin when the sun is everywhere? Lots and lots of holes in that evolution theory.There is no "top" to the evolution process; there is no goal. There is no distinct advantage to being able to look at the sun, for example -- so there is no Selection Pressure for this trait to be propagated differentially more onto future generations, once it happens.

[Mangetout]

Well I think of evolution as saying if you wait long enough all combinations of atoms will happen thus there is no creator or plan. Some of these become alive, somehow, and reproduce right away, somehow.

I don't believe much of it because if I go for a walk in the woods and see a squirrel atop a junk TV set I'd have to believe they BOTH just randomly formed there then, they are so adamant there is no maker of anything. When I believe the 1957 Chevy cars just spontaneously formed in 1957, then I will believe the squirrel in the park did as well. I actually have less problem with that occasionally something could randomly form, but that it is alive and that it just happened to be able to reproduce, now there is the problem.

The other problem is it fails to explain LIFE or why scientists cannot give life to something. They know every element in a cell yet cannot build a living one, why? They could even make it larger so easier to work with, but they seem to make not a thing alive while claiming it just formed randomly in a pond. Well, then go make us some of those. I notice all evolutionists never talk about why they cannot create life, and it is supposed to be easy once you set up the right materials. If they cannot even BEGIN their process, why would I want to believe the rest of it?
None of this has anything much to do with evolution.

[MrDibble]

Biological Evolution is change in allele frequency over successive generations within a population that shares a gene pool. This occurs by natural selection (either punctuated or gradual, take your pick) and genetic drift. I can expand on any big words if anyone needs me to, but that's the Cliff Notes about what I know about evolution.

The theory of evolution can also be applied to other entities with similar variation as biological organisms (all that is needed is heritability and differentiation), so some people have tried to apply it to memes, to computer programs, etc. These haven't all been that convincing, IMO.

[Czarcasm]

The problem with the random mutation idea are several, there would be so many bad changes most would die out, and worst of all, the same bad changes would occur over and over because nothing is keeping track. Instead we see animals getting more adjusted to their environment.

Speaking of mutations, sure there are some, cancer, isn't that a mutation, uncontrolled cell growth. Just what an evolutionist wants to see, but the problem is when has cancer ever grown a new organ, or anything beneficial?

It is just that sort of random error you all say makes these new organs and such and then the stronger of those survive, OK, where are the beneficial changes from cancer then? Why aren't we seeing new organs and tissues develop in animals randomly all the time and some better than before?

We are also supposed to always adjust to stuff that lasts a long long time, so why can't we look at the sun? It has been at about same brightness billions of years. Why also don't we love to feed on the most common thing that could sustain us, grass and leaves? Wouldn't this selection process of who survives favor those who can eat the most common things available?

Above all how would we have evolved to eat cooked food, with none of that to be found in the environment and to only like 70 degree temperatures when no where on earth has that regularly? Then look at our lousy feet, we can't even walk in the jungle or run from prey in bare feet, yet we are at the TOP of the evolution process?

Where is our night vision and blood hound nose and wide temperature range if we are at the top? Why do we burn up with sunburn with only a few hours exposure, animals don't, even those with little fur, how is our skin an improvement and where would we develop such skin when the sun is everywhere? Lots and lots of holes in that evolution theory.You do realize that this is not actually a debate about evolution, don't you? Do you have anything more to add about your personal knowledge about the subject?

[Mangetout]

Where is our night vision and blood hound nose and wide temperature range if we are at the top? Why do we burn up with sunburn with only a few hours exposure, animals don't, even those with little fur, how is our skin an improvement and where would we develop such skin when the sun is everywhere? Lots and lots of holes in that evolution theory.It's clear that you're quite mistaken about what the theory of evolution actually is. I would reserve your criticism of it until you at least understand what you're disagreeing with.

[jjimm]

The problem with the random mutation idea are several, there would be so many bad changes most would die out, and worst of all, the same bad changes would occur over and over because nothing is keeping track.You contradict your first statement. Changes bad enough would cause the organisms to die out. Changes that are mostly benign but not fatal may not have a huge effect initially, but could mean a group containing this change may fare just-a-little worse against a group that doesn't contain the change - and die out too, or adapt in other ways.Instead we see animals getting more adjusted to their environment.Well yeah, that's the point. The ones that didn't, died out.

[MrDibble]

Above all how would we have evolved to eat cooked food, with none of that to be found in the environment and to only like 70 degree temperatures when no where on earth has that regularly?We evolved to eat anything we could get our hands on. That cooked food is easier to digest is a happy accident, yay us! But we are perfectly capable of digesting both raw meat and fruit and vegetables. All of which are calorifically denser than the grass you'd have us grazing on. And plenty of places on Earth are regularly that hot or hotter, some of them very close to where we evolved. Then look at our lousy feet, we can't even walk in the jungle or run from prey in bare feet, yet we are at the TOP of the evolution process? Are you under the delusion that your soft Western feet are natural? Or even the norm, historically? It'd only take a few weeks of running barefoot for you feet to toughen up have to hobbit-level soles.

Where is our night vision and blood hound nose and wide temperature range if we are at the top?In the best place to keep them - our brains! Brains that have led us to develop IR goggles, domesticate wolves and breed bloodhounds from them to do our sniffing for us, and brains that combine with our nimble fingers to make the clothes, houses, AC and furnaces that let us have a wider living range than any other animal. Why do we burn up with sunburn with only a few hours exposure, What do you mean "We", White Man? I don't burn in my natural environment, even naked.how is our skin an improvement and where would we develop such skin when the sun is everywhere?I'd explain the cost/benefit analysis of UV damage vs vitamin D production, but I'm not sure you'll care. Lots and lots of holes in that evolution theory.

[Silverstreak Wonder]

Interesting, how when the questions get hard, well just tell him it is not a debate. I think it being in "great debates" kind of weakens that argument a bit. Then a guy says well we are not at the top, yet everything that survives and reproduces after all these eons is supposed to be the winners in natural selection. Hmmmmm.....

So why do we get sunburned so easy and want 70 degree temp all the time and need cooked food, under a "strongest, best survive" natural selection process? Where were we all those years to develop "evolve" these traits, which are so bad for living here? How would that happen if the theory is true? Why aren't we eating a live mouse whole and loving it? I am giving my view on evolution, that it is a false theory and here is why, so I am on topic folks.

[Silverstreak Wonder]

MrDibble, well then under your ideas, why didn't the white man die out then? The problem with us developing brain instead of better abilities would make us lunch for the animals with the better organs while we were slowly getting that brainpower. Yes, still lots of holes in the theory.

[Skald the Rhymer]

OK -- going by the rules and having read nothing but the OP:

In a real nutshell....

1. Random mutations.
2. Natural Selection ("survival of the fittest.")
3. LOTS of time for stuff to happen.

Really, that's pretty much all there is to it -- all the rest is, in a sense, commentary. E.g., I know some or a lot about Punctuated Equilibrium, Gene Diversity, Isolated Populations and why they change, Genetic Similarity, why we aren't "descended" from chimps, or even from monkeys... etc.... But in the end it pretty much boils down to the three points above.

I've included "time" in the basic points, because a lot of otherwise intelligent and open minded people just can't wrap their minds around just how much change can accumulate over time, in tiny, invisible increments.

I am quite vexed that you remembered to include time when I did not. ;)

[capeo]

MrDibble, well then under your ideas, why didn't the white man die out then? The problem with us developing brain instead of better abilities would make us lunch for the animals with the better organs while we were slowly getting that brainpower. Yes, still lots of holes in the theory.

I always love when people show, demonstrably, that they have absolute no clue what evolution posits and then claim holes in the theory. To make such a claim you'd have to actually understand evolution in the first place. And if you did you would not ask such ridiculous questions. We need cooked food? We can't survive barefoot? White skin? Really? Wow, read a book, man. It's not even worth debating such preposterous claims when they are so demonstrably wrong. Instead, some facts: We can eat just about anything organic and don't, in any way, need to cook food. Walk around barefoot for a summer and then ask about your feet. You do realize there are many indigenous cultures around the world that never where shoes right? White skin evolved in northern climes where the sun is less intense to boost Vitamin D production. And I have no clue what you're talking about animals with "better organs". WTF does that mean?

[Skald the Rhymer]

And I have no clue what you're talking about animals with "better organs". WTF does that mean?

There's a beaver colony in northern Ontario with an absolutely awesome pipe organ. Prettiest thing I ever heard. And the lead organist operates it using only teeth and tail.

[hotflungwok]

Interesting, how when the questions get hard, well just tell him it is not a debate. I think it being in "great debates" kind of weakens that argument a bit. Then a guy says well we are not at the top, yet everything that survives and reproduces after all these eons is supposed to be the winners in natural selection. Hmmmmm.....
There is no winner. There is just species that haven't died out it. It's not a process with a goal, it's just a process.

So why do we get sunburned so easy
Who's we? Go ask an African about sunburn. You get sunburned easily because your ancestors didn't have a survival based reason to develop large amounts of melanin.

and want 70 degree temp all the time
Again, who's we? Go ask an Eskimo how much he likes 70 degree temps. Then ask a desert nomad the same thing.

and need cooked food,
We need cooked food? Are you sure?

under a "strongest, best survive" natural selection process?
What do any of these things have to do with surviving long enough to pass your genes on? You haven't named any traits that are directly affected by natural selection in humans.

Where were we all those years to develop "evolve" these traits, which are so bad for living here? How would that happen if the theory is true? Why aren't we eating a live mouse whole and loving it? I am giving my view on evolution, that it is a false theory and here is why, so I am on topic folks.
Um, to be blunt, why should we care about your view? You are clearly very ignorant about evolution, and are basing your arguments on this ignorance rather than any actual knowledge. Before you dismiss evolution based on the completely ridiculous idea that we should be eating and enjoying live mice, maybe you should try learning about it and try to find out why this idea is so ridiculous.

[jjimm]

Then a guy says well we are not at the top, yet everything that survives and reproduces after all these eons is supposed to be the winners in natural selection.OK, maybe you'll understand this: we are at the "top", but we share this "top" with everything else alive. We are at the top of our tree, because we have evolved to fit the niche in which we evolved (and our big brains have allowed us to survive in niches for which we didn't evolve), but a sea slug is at the top of its tree too, as is a nematode worm, and a streptococcus bacterium, a cactus, and a fern - they're all at the top of their trees too. There is no purpose and no grand scheme to evolution, and no "winner": it just is. Everything currently alive is in that position because it has failed to die out, and that includes humans.

[Silverstreak Wonder]

Yeah, when you don't have an answer, well science just shouldn't discuss the issue. Reminds me of your alls steady state theory.

Well I never got anyone to say why they can't create even a single cell living thing in a lab using what evolution says was in the pond, water, the elements in the table, a nice 70 degree temp, light, etc. Since you all have living cells to reverse engineer, it ought to be a snap to make one.

By the way, an additional evolution question about life. If it "just happens" why can't you heat a cell till it just barely dies, but is not damaged physically and then go back to the room temperature with food all around it and have it just come back to life? I mean everything is all built so why isn't it alive again? This assumes the cell is totally dead now, not just in a suspended state. Wouldn't evolution theory say the cell ought to become alive again?

[tdn]

Interesting, how when the questions get hard,

No offense, but your questions really aren't all that hard. They've all been answered.

But I do wonder about the cooked food thing. I remember starting a thread about nutrition a few years back, and I remember people posting something about that. Basically the idea was that as we developed the ability to create fire, we formed the habit of cooking food, and our digestive systems evolved to sort of depend on that.

Is that not correct?

[MrDibble]

MrDibble, well then under your ideas, why didn't the white man die out then? Why should they? I'm pretty sure white men post-date the discovery of fire, clothing, tents and caves, all of which mean Homo Blanco needn't do everything under full sunlight. The problem with us developing brain instead of better abilities would make us lunch for the animals with the better organs while we were slowly getting that brainpower.Sometimes. By this "theory" of yours, there should be no lesser animals at all - why have chimps, monkeys, etc survived?

[Skald the Rhymer]

Yeah, when you don't have an answer, well science just shouldn't discuss the issue. Reminds me of your alls steady state theory.

Well I never got anyone to say why they can't create even a single cell living thing in a lab using what evolution says was in the pond, water, the elements in the table, a nice 70 degree temp, light, etc. Since you all have living cells to reverse engineer, it ought to be a snap to make one.

By the way, an additional evolution question about life. If it "just happens" why can't you heat a cell till it just barely dies, but is not damaged physically and then go back to the room temperature with food all around it and have it just come back to life? I mean everything is all built so why isn't it alive again? This assumes the cell is totally dead now, not just in a suspended state. Wouldn't evolution theory say the cell ought to become alive again?

You know, the rules in the OP only forbid reading other posts BEFORE you make your first one. AFTER you make you first post, it's perfectly fine to read all the responses. In fact, it might lead to more cogent and reasoned responses on your part.

[msmith537]

The problem with the random mutation idea are several, there would be so many bad changes most would die out,


Exactly.



and worst of all, the same bad changes would occur over and over because nothing is keeping track. Instead we see animals getting more adjusted to their environment.

Predators looking for the weakest animals and environmental conditions sort of "keep track".




Where is our night vision and blood hound nose and wide temperature range if we are at the top? Why do we burn up with sunburn with only a few hours exposure, animals don't, even those with little fur, how is our skin an improvement and where would we develop such skin when the sun is everywhere? Lots and lots of holes in that evolution theory.

You mean like these guys? (http://upload.wikimedia.org/wikipedia/commons/5/55/US_Navy_SEALs_with_laser_designator_closeup.jpg)

Our brain gives us an evolutionary advantage far superior to any other animal. It is the ability to make tools and other implements to shape and adapt to our environment.


The best way I can describe evolution is this. I don't need to outrun the bear. I just need to outrun you. IOW, I don't need to be genetically perfect, just good enough to survive long enough to reproduce.

[MrDibble]

Once again... So why do we get sunburned so easy"We" don't and want 70 degree temp all the timeThat's pretty much the temp in the nice parts of my country all year round. and need cooked food,Can you give us some sort of justification for this "need cooked food" crap? under a "strongest, best survive" natural selection process?That is not the process of natural selection. NS says the fittest will survive, not the strongest. And by "fittest", it means "best adapted". Point out a more adaptable animal than man, please? Where were we all those years to develop "evolve" these traits, which are so bad for living here?South Africa, where the living is easy.Why aren't we eating a live mouse whole and loving it?Because we can get springbok carpaccio now.

[tdn]

Well I never got anyone to say why they can't create even a single cell living thing in a lab using what evolution says was in the pond, water, the elements in the table, a nice 70 degree temp, light, etc. Since you all have living cells to reverse engineer, it ought to be a snap to make one.

Personally, I make them all the time. So do you.

By the way, an additional evolution question about life. If it "just happens" why can't you heat a cell till it just barely dies, but is not damaged physically and then go back to the room temperature with food all around it and have it just come back to life? I mean everything is all built so why isn't it alive again? This assumes the cell is totally dead now, not just in a suspended state. Wouldn't evolution theory say the cell ought to become alive again?

It's hard to make any sense of this, but are you implying that evolution is some form of ressurection?

[jjimm]

Wouldn't evolution theory say the cell ought to become alive again?No, it wouldn't. Why would it? (And what has evolutionary theory got to do with the question?)

[Revenant Threshold]

Evolution doesn't mean perfection. It just means that generally the things that survive will be fitter, more adapted to their environment, than those that don't. It doesn't mean they must be perfectly adapted, or have every ability or skill that they could use; just that they are better adapted than those which died out.

[Silverstreak Wonder]

jji, it would because in that dead cell are all the same things that were present when it was alive, and nothing is "keeping track" so it would not know not to be alive again just because it died before in hotter conditions.

Tdn, When you build body cells or even create a baby you always start from living material passing on its life by splitting or combining, a sperm is alive for instance. Lets se you make life out of something not alive, I don't do that in my body, but evolution says it just happened randomly. So, explain why a dead cell does not return to life if it is otherwise not damaged when the heat is removed? All ingredients for life are in place.

[Mangetout]

Interesting, how when the questions get hard, well just tell him it is not a debate.No, that was specified by the OP. If you want a debate, you're most welcome to open a separate thread in GD. If you wish to interpret this as further evasion, I'll be delighted to open the thread for you and invite you there.

Nearly everything you have said about evolution in this thread is nonsense. You're not going to find everyone here running away from the opportunity to debate you on it.

[jjimm]

jji, it would because in that dead cell are all the same things that were present when it was alive, and nothing is "keeping track" so it would not know not to be alive again just because it died before in hotter conditions.What does that even mean? If you damage the structures and chemicals in a cell beyond repair, it will die. It's absolutely sweet fanny adams to do with evolution, or abiogenesis, which is what I presume you're hinting at, which isn't the same thing as evolution. You need to distinguish the two if you're going to talk about the subject.

[tdn]

So, explain why a dead cell does not return to life if it is otherwise not damaged when the heat is removed? All ingredients for life are in place.

If the heat killed it, it was damaged beyond repair.

[capeo]

Yeah, when you don't have an answer, well science just shouldn't discuss the issue. Reminds me of your alls steady state theory.

Well I never got anyone to say why they can't create even a single cell living thing in a lab using what evolution says was in the pond, water, the elements in the table, a nice 70 degree temp, light, etc. Since you all have living cells to reverse engineer, it ought to be a snap to make one.

Actually, we're quite close to making cells in a lab. That's just bioengineering though, and has nothing to do with evidence of evolution.


By the way, an additional evolution question about life. If it "just happens" why can't you heat a cell till it just barely dies, but is not damaged physically and then go back to the room temperature with food all around it and have it just come back to life? I mean everything is all built so why isn't it alive again? This assumes the cell is totally dead now, not just in a suspended state. Wouldn't evolution theory say the cell ought to become alive again?

Again, this is so nonsensical that it can't even be responded to. I must have missed the "How Evolution Makes Your Steak Come Back to Life" lesson in Biology 101. After saying something this ignorant do you really expect any debate?

[capeo]

So, explain why a dead cell does not return to life if it is otherwise not damaged when the heat is removed? All ingredients for life are in place.

You've got to be joking? First off a single cell of a living organism is not alive and cannot live on its own so your question is stupid. Secondly, heat destroys protein bonds and major structures of the cell rendering them inoperative, so no, the ingredients of life are not in place.

And none of this crap is in any way posited by evolution. Jeebus. Learn what abiogenisis is, why it has little to do with evolution, then come back with sensible questions.

[SciFiSam]

Response without reading the rest:

Evolution is the physical processes by which changes happen from generation to generation - mutation and recombination. Natural selection is the process by which these changes happen. At least, most people accept that that's how these changes happen - there are competing theories by Lamarck (who was writing before Darwin) and others.

Natural selection is about survival of the fittest. This means 'the ones that fit into their environment best,' not the strongest, fastest ones, though obviously sometimes the strongest, fastest ones often do have advantages.

In other words, the animals that have features which, in comparison to the other creatures around them, enable them to:

Live a long time after sexual maturity

Obtain a mate

Have successful pregnancies

Look after their offspring well (even if that means choosing the best place to drop their clutch of eggs then leave them to their own devices)

... are more likely to be able to pass their genes on to the next generation.

For example, if the animal lives in an environment where the are are bushes that produce fruit all the way from one foot up to twelve foot up, then the animal that can reach a couple of inches higher than the others around it has an advantage. While its fellows are squabbling over the lower branches our tall guy can strecth up to the extra fruit above. This animal is less likely to be killed in a fight over resources and less likely to suffer from starvation or malnutrution.

The reason for the initial differences between these creatures is that, when genes are copied, sometimes mistakes are made. For example, the genes that keep a young animal growing taller might switch off later than they're 'supposed' to (though that's a gross simplification, of course).

Creatures that produce sexually have another mechanism for evolution: that slightly taller animal might mate with an animal that also has slightly better depth perception, and some of their offspring will end up with both advantages.

Evolution does NOT mean that 'everything has a purpose.' Some features of animals are not there because they offer a particular advantage, but because they don't offer a disadvantage. Other features might be detrimental to an individual because they're side-effects of a gene (or collection of genes) which can give an advantage. For example, the gene for sickle-cell anaemia, which gets passed on because carriers also have resistance against malaria.

Other traits - like cancer in old age - persist partly because they don't much affect whether the individual will be able to live a long time after sexual maturity and so on.

It all takes a long, long time. One creature cannot 'evolve' into another - it's something that happens across the generations.

[tdn]

I must have missed the "How Evolution Makes Your Steak Come Back to Life" lesson in Biology 101.

I remember that it had something to do with LSD.

[Silverstreak Wonder]

Capeo, it has everything to do with evolution, if you cannot create life from non living elements then the whole theory goes right down the drain because it depends on that and just randomness to do it all.

Oh and of course a single cell can be alive, ever heard of an amoeba? That is the kind of life I want to see you all build, yes you always say it is close. I heard same thing 40 years ago, any day now......yeah. They will be saying that to your grand kids too.

I think when they do totally map DNA they will find there were few mutations, and those died, but rather that what developed was just choices available in the DNA code all the while, designed in other words, maybe triggered to be used by environmental factors.

[Rumor_Watkins]

I wasn't aware that evolutionary theory had anything to say about the ultimate origin of life?

[kevlaw]

Evolution in less than 10 words:

Individuals vary.
Variation is inherited.
Fittest individuals reproduce more.

[Skald the Rhymer]

No, that was specified by the OP. If you want a debate, you're most welcome to open a separate thread in GD. If you wish to interpret this as further evasion, I'll be delighted to open the thread for you and invite you there.


Actually, as the person who wrote the OP, I have to say it wasn't my intention to stifle debate. (Otherwise we'd be in MSPIMS.) I just wanted persons to make their first posts (or, really, just for the first dozen posts or so) based on personal knowledge rather than information refreshed by recourse to reference works. The idea was to elicit mistaken impressions so that others might correct them.

That implies to me as well, by the way, though I don't think my thoughts on evolutionary theory are as fantastical as Silverstreak's.

[Skald the Rhymer]

Capeo, it has everything to do with evolution, if you cannot create life from non living elements then the whole theory goes right down the drain because it depends on that and just randomness to do it all.
.

Evolution has jack all to do with the origin of life. Evolution is the scientific explanation for the diversity fo species. There is no scientific theory for the origin of life as I understand it.

Please understand, by the way, that theory means something different in science than it does in common parlance. A scientific theory is an explanation for a given phenomenon that has been rigorously tested in an attempt to disprove it, and, having so far survived such attempts, is currently accepted by the community of the relevant discipline.

And if one of you guys could poke holes in that definition to make it more rigorous, that'd be great.

[Silverstreak Wonder]

Rumor, you never heard about the pond scum we are all supposed to be from? Ahhh, it had to be made alive, seems kind of important to explaining all these animals and stuff...if you need a creator for any part of what all has happened then the theory of evolution fails, that is just how it is.

Yeah maybe they do try to lock it out since it would disprove the theory. I know I was similarly told it is stupid to question the steady state theory in 1950's, even though it did not explain life either. If any theory does not include this info I know it is false by now. I remember so many false things, the craters on the moon were all volcanoes, and on and on. Each time something comes up to disprove it, well just leave it out, say it works fine if we just don't consider all the facts. Yeah, great science.

[Rumor_Watkins]

Rumor, you never heard about the pond scum we are all supposed to be from? Ahhh, it had to be made alive, seems kind of important to explaining all these animals and stuff...if you need a creator for any part of what all has happened then the theory of evolution fails, that is just how it is.

Yeah maybe they do try to lock it out since it would disprove the theory. I know I was similarly told it is stupid to question the steady state theory in 1950's, even though it did not explain life either. If any theory does not include this info I know it is false by now. I remember so many false things, the craters on the moon were all volcanoes, and on and on. Each time something comes up to disprove it, well just leave it out, say it works fine if we just don't consider all the facts. Yeah, great science.

"life" doesn't disprove evolution, guy. it's a sine qua non of the fucking theory.

[Voyager]

1. Descendants of an organism have slightly different characteristics from the parent or parents.
2. This leads to a diverse population of the organisms.
3. Due to limits on food and/or predators, not all members of a population will reproduce.
4. The characteristics which favor reproduction will eventually predominate in a population.
5. For various reasons, two subpopulations can be isolated. Over time, the change in characteristics as both subpopulations evolve may cause members to be unable to interbreed. This is speciation.

While in our world we are all related, we can imagine evolution happening on two totally unrelated populations. It is still evolution.

Now I can look at the other responses.

[Superfluous Parentheses]

Don't really see what this is for, but here goes: I'm a layman in these matters. What I remember is from high-school science, some documentaries I've seen and the excellent book "The Greatest Show on Earth" by Dawkins. Any errors in this post are most probably mine.

I would roughly define evolution as the changing of the characteristics of groups of organisms over time. The theory of evolution states that these changes are due to variance in reproduction (mostly*) and selective pressures of the environment.

The variance in reproduction is partly due to mutations - changes to the genes** themselves due to rare copying errors or other factors - but for sexually reproducing organisms it's mostly due to the "mixing" of genes from the parents - a child gets two equivalent genes (one from each parent) for most genes. This mixing does not change the genes - you just get a selection out of what's called the gene pool: an interbreeding population has a bunch of variants for most useful genes, and you get one or two of each when the parents reproduce.

The selective pressures are anything the organism "experiences" during its life that might be influenced by the inherited information (the genes): a gene that increases your metabolism may help you in running faster when hunting/running away, but it's a liability when food is scarse. Note that for these purposes, other members of the same species do provide selective pressure. Whenever an organism dies before reproducing, that removes one copy of its genes from the gene pool. Whenever an organism has an improved gene set that helps it cope better than its rivals, that increases the copies of those genes. This is called natural selection. Over time, the successful genes "take over" and the unsuccessful ones die out. This means that populations overall adapt to their environment - they change (they may get bigger, or smaller, or evolve different teeth etc).

If for some reason a population (or perhaps more accurately; the gene pool) is split up (does not interbreed) for some time, the selective pressures can drive the two groups in different directions (dropping certain genes from the pool in one group, while exaggerating them or accepting new mutations in the other), which can result in the two groups not even being able to interbreed after some amount of time. This is speciation.

There is overwhelming evidence that all organisms that have so far been researched are related - and the structure of DNA/genes themselves are one of the strongest pieces of that evidence - leading to the theory that all current life on earth evolved by branching and rebranching etc... from a single source species. Meaning we are not just related to the chimpanzee, but also (much more distantly) to the sponge and the potato. See "the tree of life". How that original species arrived on the planet is not part of the theory of evolution.

* As far as I know, certain single cell organisms can transfer their genes between individuals directly, even across species. So there the story is different. This also means that for those species, their inheritance tree isn't a tree at all. There are more of these kinds of exceptions to be found.

I could probably go on a bit about the likely evolution of the eye, which is interesting, and some of the evidence for the theory of evolution, which is also interesting but full of hard to remember details.

In any case, for a simple acceptance of evolution pretty much all you need to accept is that reproduction is not perfect and that some inheritable characteristics of a species are better at surviving in their current environment than others. Oh, and that the earth is a LOT more than 10,000 years old.

I also know plenty annoying straw men / misconceptions / misleading creationist arguments, but I get bored by them.

** ETA: genes are the molecules that hold the information that determines how an organism grows. Variances in genes (or additions or deletion of genes) can result in small or dramatic changes in the "final" organism. Genes do not necessarily influence any specific trait - they can have a local effect or influence a bunch of "unrelated" functions or even work only in combination with other genes. Genes are what gets passed on during reproduction - even when that reproduction is just a simple splitting of a cell into two new ones.

[Voyager]

Someone once posted this in a thread about evolution:

Try everything.
Kill whatever doesn't work.
Repeat.

Amusing, but it has a fatal flaw. Evolution does not find global optima, only local ones, exactly because nature does not try everything, just a subset of things.

[SciFiSam]

Rumor, you never heard about the pond scum we are all supposed to be from? Ahhh, it had to be made alive, seems kind of important to explaining all these animals and stuff...if you need a creator for any part of what all has happened then the theory of evolution fails, that is just how it is.

Yeah maybe they do try to lock it out since it would disprove the theory. I know I was similarly told it is stupid to question the steady state theory in 1950's, even though it did not explain life either. If any theory does not include this info I know it is false by now. I remember so many false things, the craters on the moon were all volcanoes, and on and on. Each time something comes up to disprove it, well just leave it out, say it works fine if we just don't consider all the facts. Yeah, great science.

As others have said, evolutionary theory simply isn't talking about the origin of life itself. It's talking about the reason we have different species.

Imagine I take a university course in 1st world war poetry. Would you criticise that course if it didn't talk about the history of the invention of paper? No, because the course isn't about that.

The very word evolution means 'change.' Not 'how stuff started.'

[DanBlather]

Rumor, you never heard about the pond scum we are all supposed to be from? Ahhh, it had to be made alive, seems kind of important to explaining all these animals and stuff...if you need a creator for any part of what all has happened then the theory of evolution fails, that is just how it is.That's demonstratively untrue. In computer science there are genetic algorithms that use random changes to the code to become more suited to the task. The code was "created" initially, and a set of rules were specified, but what happens after that is the result of random modifications and the selection of the "best" candidates for the next round of mutations. The end result can not be predicted in advance, and if repeated the program will almost certainly produce a different solution.

How does this relate to evolution? Well God may have created the initial conditions for life and put into place the physical laws governing the universe and then sat back and let it rip. If we look at the evidence God left it is clear that each organism was not created from scratch. We can see the progression of simpler organisms to more complex ones, each one building upon the structure of the previous generations.

One can argue that it is more magnificent to envision a God that put together a set of initial conditions that resulted in man rather than a God that sat down and directed the development of hundreds of thousands of species, most of them becoming dead ends.

It is a sacrilege to ignore the fossil evidence that God has left behind for us to see. The Bible and other sacred books had to be written through fallible men, but the physical evidence was left directly by God. Do you really want to doubt his work?

[Voyager]

Well I think of evolution as saying if you wait long enough all combinations of atoms will happen thus there is no creator or plan. Some of these become alive, somehow, and reproduce right away, somehow.

You think wrong. Now, life began with a self-replicating molecule, like RNA. Viruses reproduce -do you consider them alive or not?

I don't believe much of it because if I go for a walk in the woods and see a squirrel atop a junk TV set I'd have to believe they BOTH just randomly formed there then, they are so adamant there is no maker of anything. When I believe the 1957 Chevy cars just spontaneously formed in 1957, then I will believe the squirrel in the park did as well. I actually have less problem with that occasionally something could randomly form, but that it is alive and that it just happened to be able to reproduce, now there is the problem.

I did that, but I was too busy looking at the watch I found to notice the TV.

The other problem is it fails to explain LIFE or why scientists cannot give life to something. They know every element in a cell yet cannot build a living one, why? They could even make it larger so easier to work with, but they seem to make not a thing alive while claiming it just formed randomly in a pond. Well, then go make us some of those. I notice all evolutionists never talk about why they cannot create life, and it is supposed to be easy once you set up the right materials. If they cannot even BEGIN their process, why would I want to believe the rest of it?
When simple cells are created, will you then accept evolution? It will happen.

Here is an analogy about randomness. Say you have a really complicated lock to open. It has 1,000 stage, each with ten numbers, and to open the lock you have to get every number set correctly, in sequence. Think you can do it? With 10**100 combinations, it might approach the complexity of the cell.

But I forgot to mention something. When you get the right number at each stage, you can hear a click. Now the lock is trivially simple to open, since you go through all the ten numbers at each stage, and when you hear a click, move to the next. That's how life evolved. It didn't pop out fully formed, but slowly and incrementally changed over time. The random walk of life kept some fairly simple and successful life forms, but also led to complicated ones like whales and us. At each stage there was a species that was successful in its niche and in its time. We are way different from pond scum, but not so different from either chimps or our common ancestor.

BTW, what did you base your response on? Have you ever read an actual book on evolution?

[Inner Stickler]

Rumor, you never heard about the pond scum we are all supposed to be from? Ahhh, it had to be made alive, seems kind of important to explaining all these animals and stuff...if you need a creator for any part of what all has happened then the theory of evolution fails, that is just how it is.

Yeah maybe they do try to lock it out since it would disprove the theory. I know I was similarly told it is stupid to question the steady state theory in 1950's, even though it did not explain life either. If any theory does not include this info I know it is false by now. I remember so many false things, the craters on the moon were all volcanoes, and on and on. Each time something comes up to disprove it, well just leave it out, say it works fine if we just don't consider all the facts. Yeah, great science.No scientist would 'lock out' data that disproves a theory. They'd write a smug paper explaining in great detail why the current theory is erroneous and there'd be huge debates and a mad scramble as every else tries to test the same phenomenon and at the end we either have a stronger current theory or a new current theory. Science is never set in stone. We can never find The Truth. We can only rule out The Untruths. So we have things like The Law of Gravity. For all intents and purposes it appears to accurately predict the effects of gravity on all phenomenon. If someone performs an experiment where the Law of Gravity is unable to make an accurate prediction, then we need to examine the law and the experiment to find the discrepancy. You are more than welcome to disagree with a scientific principle. However, if you're going to disagree, it would behoove you to have a similarly valid principle that replaces it. God did it is untestable, makes no predictions and is not even about evolution but rather the beginning of life and therefore not within the scope of this thread.

[capeo]

Rumor, you never heard about the pond scum we are all supposed to be from? Ahhh, it had to be made alive, seems kind of important to explaining all these animals and stuff...if you need a creator for any part of what all has happened then the theory of evolution fails, that is just how it is.

Yeah maybe they do try to lock it out since it would disprove the theory. I know I was similarly told it is stupid to question the steady state theory in 1950's, even though it did not explain life either. If any theory does not include this info I know it is false by now. I remember so many false things, the craters on the moon were all volcanoes, and on and on. Each time something comes up to disprove it, well just leave it out, say it works fine if we just don't consider all the facts. Yeah, great science.

First off, and if you read even the littlest bit of science you'd be aware of this, we have mapped complete genomes for many species and they do indeed show near endless amounts inherited mutations, so again, I have no clue what you're talking about. Evolution, as in inherited mutations, is absolutely proven and observed so all you denialism is really moot. And evolution in NO WAY posits how life started. That is simple not its purpose. What it does unequivocally show is that all life we have so far examined has common ancestry and that the diversity of life has arisen through evolution. The first life on the planet is the study of abiogenisis. A different subject altogether. It is also idiotic to state that we need to replicate an event to prove that event took place. We would no nothing about anything if applied that criteria to any field of study. So some creator made the stars because we can't make one? Or do they just not exist because we can't replicate one? Your argument is childish and better know as the God of Gaps argument. You fill in our gaps in knowledge with your god though it isn't needed. We'd still be hunter gathers if we took your outlook and applied to science. "Gee, we don't know how this happened. Well, it must have been God so I'm not going to bother to look into any deeper." Luckily for us rational thinkers with even an iota of patience the gaps keep getting smaller and smaller.

[Marley23]

Silverstreak Wonder, if you want to try to debate against evolutionary theory, please start a new thread. If not, I suggest you read the other posts in this thread. You might learn something about the subject you are discussing. EDIT: I'm also advising all the other posters to let go of this tangent.

[Silverstreak Wonder]

Inner, in your post 73, you say no scientist locks out data, then by the last sentence you lock the origin of life right out of it anyway. Kind of funny. Again it shows how if it does not fit, just leave it out.

Well the origin of life is certainly required to go from elements in a pond to living things, I have never seen a piece of iron reproduce itself, so seems like the living process is rather important to the evolution theory. Since it can't be figured out, well just leave it out like it is not an important fact?

Several others have the same problem, they basically say, well this works if you just ignore what life is and how it came about. How can that be good scientific method? If life fits evolution then prove it does. Otherwise, false theory.

[Superfluous Parentheses]

The theory of evolution doesn't explain the origin of life just like the theory of gravity does not explain the origin of mass.

Anyway, I note that I forgot to mention in my post above that evolutionary speaking, inheritable traits are only relevant to the extent that they influence reproduction. For humans, this means that there has been very little evolutionary pressure to keep most of us alive after 40 or 50 (when historically speaking we've done most reproducing and the kids can live on their own), which is part of the explanation why there are all kinds of health problems related to reaching "old age".

[Voyager]

Inner, in your post 73, you say no scientist locks out data, then by the last sentence you lock the origin of life right out of it anyway. Kind of funny. Again it shows how if it does not fit, just leave it out.

Not to debate, but to correct a factual error - plenty of scientists are looking at the origin of life. It just doesn't fall under the umbrella of evolution. Please google "abiogenesis" for details.

[Darwin's Finch]

Let me esplain. No, there is no time - let me sum up:

Natural selection, genetic drift, sexual selection, mutations, DNA & RNA, common descent, speciation, extinction, ontogeny, phylogeny, phenotype, genotype, fitness, constraints, homology, analogy.

I can expound at length on any of those topics, but there's way too much to go into for a basic summary. If anyone's ever read anything I've written on these boards, they should have an idea what I do / do not know :)

[TimeWinder]

Silverstreak Wonder, if you want to try to debate against evolutionary theory, please start a new thread. If not, I suggest you read the other posts in this thread. You might learn something about the subject you are discussing. EDIT: I'm also advising all the other posters to let go of this tangent.

Actually, the OP has indicated that the debate is intended; he just wanted to get some initial off-the-cuff understandings into the thread first. I think the "tangent" may be the intention. Can we get a moderator re-eval?

[Skald the Rhymer]

Marley, forgive me if this belongs in ATMB, but I don't think debating evolutionary theory is out of place here. From the OP:

Once you're past your first entry, cite (and call for cites) to your heart's consent. Likewise, you may point out errors, misconceptions, incomplete ideas, and misleading statements in previous posts. Just try to leave your swords in their scabbards, revolvers in their holsters, and axes in whatever you store your axes in.

The last sentence was merely intended to forestall a Xtians sucks! / Scientists are spawn of Mephistopheles! situation.

[SciFiSam]

Silverstreak Wonder, if you want to try to debate against evolutionary theory, please start a new thread. If not, I suggest you read the other posts in this thread. You might learn something about the subject you are discussing. EDIT: I'm also advising all the other posters to let go of this tangent.

Why?

[Superfluous Parentheses]

I'm ignoring the mod notice at this point, but I think I'm well within the intent of the thread.

Well I think of evolution as saying if you wait long enough all combinations of atoms will happen thus there is no creator or plan. Some of these become alive, somehow, and reproduce right away, somehow.

(Taking from your original post)

Well there's your poblem. That is not what the theory of evolution is. What you are talking about is your own interpretation of something that isn't even evolution. As others have said, you seem to be talking about abiogenesis (http://en.wikipedia.org/wiki/Abiogenesis).

[Czarcasm]

Why?Because he has yet to show us what he does know about evolution-which is the initial purpose of this thread.

[Czarcasm]

Silverstreak Wonder, please tell us what you know about evolution.

[Marley23]

I saw Silverstreak Wonder's topic as being separate from the one Skald the Rhymer proposed, but if everyone's okay with it being included, I'm happy to waive it. Party on, Wayne.

Silverstreak Wonder, if you would post what you do know about evolution, it would be a helpful contribution to the thread.

[SciFiSam]

Because he has yet to show us what he does know about evolution-which is the initial purpose of this thread.

Yes, he has. The knowledge he has is wrong, that's all.

[Czarcasm]

Yes, he has. The knowledge he has is wrong, that's all.I've seen a bunch of misleading questions followed by dismissals galore("Dismissals Galore" was the one woman Bond couldn't get, btw), but I haven't seen him post what he himself knows.

[SciFiSam]

Inner, in your post 73, you say no scientist locks out data, then by the last sentence you lock the origin of life right out of it anyway. Kind of funny. Again it shows how if it does not fit, just leave it out.

Well the origin of life is certainly required to go from elements in a pond to living things, I have never seen a piece of iron reproduce itself, so seems like the living process is rather important to the evolution theory. Since it can't be figured out, well just leave it out like it is not an important fact?

Several others have the same problem, they basically say, well this works if you just ignore what life is and how it came about. How can that be good scientific method? If life fits evolution then prove it does. Otherwise, false theory.

The theory of evolution also fails to talk about recipes for clam chowder. That's because it's not about recipes for clam chowder. It's about evolution - about changes over time.

It's the theory of evolution, not the theory of everything.

This has already been pointed out to you a dozen times, but maybe this rewording will make it get through.

Please quote this post just to demonstrate that you have actually read some of the words in this thread. You don't have to respond to the content of my post, just click 'quote.' If you don't quote this post, I'll assume you're not reading at all.

[SciFiSam]

I've seen a bunch of misleading questions followed by dismissals galore("Dismissals Galore" was the one woman Bond couldn't get, btw), but I haven't seen him post what he himself knows.

Nah - his first line was what he thinks he knows about evolution.

[Skald the Rhymer]

Inner, in your post 73, you say no scientist locks out data, then by the last sentence you lock the origin of life right out of it anyway. Kind of funny. Again it shows how if it does not fit, just leave it out. .

I think you're unclear on what the word data means.

Let me try an analogy. Say the check engine light on my car is on. I take it to the mechanic and he uses the gizmo to check the computer readout; it says that there's a fuel pump problem, but there are no clear symptoms of that, so the mechanic begins running tests to see if he can pin down the problem. At no point, though, does he ask me how I paid for the car, because it's irrelevant to the issue at hand.

That's basically what we mean when we say that the origin of life has nothing to do with the TOE. The TOE is about DIVERSITY of SPECIES.

[Voyager]

I've seen a bunch of misleading questions followed by dismissals galore("Dismissals Galore" was the one woman Bond couldn't get, btw), but I haven't seen him post what he himself knows.

To be fair to 007, he didn't care if he got dismiss or datmiss.

<d&r>

[Mangetout]

I think when they do totally map DNA they will find there were few mutations, and those died, but rather that what developed was just choices available in the DNA code all the while, designed in other words, maybe triggered to be used by environmental factors.
It's already known for sure that this isn't true. Novel mutations can be and have been observed.

[tdn]

Might as well add my own perspective.

Life is essentially a vehicle for DNA to ensure its own immortality. The DNA's genotype is a recipe for the phenotype, which essentially has the job of keeping the DNA intact until copies can be made. (That sounds so romantic!) On occasion copy errors are made, and on very rare occasions the error is beneficial to the phenotype. Evolution is when the improved phenotype can outcompete its peers for resources, which includes sexual mates. This propogates the "error" throughout the population, which as a whole gives the population an edge in the environment.

As to evolution vs abiogenesis is concerned, my own personal belief is that there's not a huge dividing line. Can we create a cell in a lab? No, because a cell itself is a highly evolved form of life. It's not the starting point of evolution, it's the result of hundreds of thousands of years of it. Real abiogenesis was when a protein molecule figured out a way to make a copy of itself. The moment that happened, evolution took over.

[Voyager]

Yeah maybe they do try to lock it out since it would disprove the theory. I know I was similarly told it is stupid to question the steady state theory in 1950's, even though it did not explain life either. If any theory does not include this info I know it is false by now. I remember so many false things, the craters on the moon were all volcanoes, and on and on. Each time something comes up to disprove it, well just leave it out, say it works fine if we just don't consider all the facts. Yeah, great science.

Good example. In the early 1950s, there were two schools of thought on the origins of lunar craters - volcanoes were never the one accepted answer, but Arthur C. Clarke leaned to them, for example. But the discussion (and I have books from the period) always acknowledged that this was speculation, because the evidence was not in. When the evidence came in, pretty much everyone went with the meteorite hypothesis - and not aware of holdouts, but it could happen.

The evidence is in with regard to evolution. It makes no more sense to believe in creationism than it does to believe that volcanoes are predominantly responsible for lunar craters - but if there was a verse in the Bible about it, I bet there would a lunar vulcanism movement.

[jjimm]

What does that even mean? If you damage the structures and chemicals in a cell beyond repair, it will die. It's absolutely sweet fanny adams to do with evolution, or abiogenesis, which is what I presume you're hinting at, which isn't the same thing as evolution. You need to distinguish the two if you're going to talk about the subject.While acknowledging that my own (almost certainly flawed) first post to this thread mentioned abiogenesis too. But ::cough cough:: at least I acknowledged the difference.

::Looks furtively about to see if anyone else noticed the self-contradiction. Nope, think I got away with it. Phew::

[TimeWinder]

While acknowledging that my own (almost certainly flawed) first post to this thread mentioned abiogenesis too. But ::cough cough:: at least I acknowledged the difference.

So did mine. I don't think it's a any great problem to acknowledge that abiogenesis and evolution are in fact related topics (one's the kick-start for the other, and you can't discuss speciation very long without asking the inevitable question about what the first "species" was).

The problem is when people don't seem to be able to separate the two as scientific topics. Abiogenesis is an active question: we really don't know how things got started, although there are a number of plausible hypothesis. Further, because we're unlikely to ever find "fossils" or other markers of the "first life," we may never have the evidence to say for sure, even when we manage to do it in the lab (we might have found an alternative mechanism).

Evolution, on the other hand, is as proven as a scientific field can be: it makes active predictions that we can--and have--tested, and has falsifiability conditions that have been tested as well. It's been witnessed, induced, and prevented in the lab. It's evident from the fossil record. And as many folks have pointed out, if we assume mutation, reproductive success as a measure of fitness, and variability of fitness to various environments, it's pretty much a required consequence: how could things NOT evolve under those circumstances?

[Boyo Jim]

Using nothing but my own brain, I know nothing about evolution, or math or science, or English.

Whiat I know without reference to other brains:
I am hungry.
I am tired.
I am horny.
I don't feel good.

That's it.

[manila]

snip I notice all evolutionists never talk about why they cannot create life, and it is supposed to be easy once you set up the right materials. If they cannot even BEGIN their process, why would I want to believe the rest of it?snip


And here is the simple beauty of it. obviously nature did set up the right conditions to create life. That and the following evolutionary steps don't actually depend on you believing it to be true.

[jjimm]

Evolution, on the other hand, is as proven as a scientific field can be: it makes active predictions that we can--and have--tested, and has falsifiability conditions that have been tested as well. It's been witnessed, induced, and prevented in the lab. It's evident from the fossil record. And as many folks have pointed out, if we assume mutation, reproductive success as a measure of fitness, and variability of fitness to various environments, it's pretty much a required consequence: how could things NOT evolve under those circumstances?Well put. It's a logical conclusion, rather than a philosophical one.

I think what our friend is saying is that his comprehension of evolution is dependent on proving abiogenesis. But we could then say "hey, add God to the abiogenesis question if you like (for the time being, until contradicted by evidence) - now have a wee think about the mechanism whereby the rest of it arises."

[Mojo Pin]

Hey sorry to butt in, but I remember a while ago Der Trihs or HMHW or maybe Voyager had a really great writeup of how evolution was simply the state of existence of almost anything in the passage of time, including non living "things". Anyone remember where that was?

[AHunter3]

Who among those who have done programming have NOT done one of these?: try everything and put it in a loop and discard the ones that AREN'T matching the desired parameters; exit loop when found

It's brute force; it may seem klunky but the one thing it has going for it is that it is exhaustive and bloody freaking well WILL find the specified parameter sooner or later.

In the case of evolution it's recursive; the loop never exits, the parameter is always tomorrow's "will survive".

[tomndebb]

Silverstreak Wonder, you have now demonstrated that you have pretty much no knowledge of evolution--either in theory or in fact--that did not leap fully formed from the typewriters of Duane Gish, (in the most favorable light), or Kent Hovind, (in the more probable view). As such, now that you have demonstrated a complete failure to actually understand evolutionary theory, you are done in this thread.

Feel free to open a new thread to discuss your beliefs, but there is no point in letting you hijack this thread with a lot of error filled drivel.

[ /Moderating ]

[psychobunny]

At the risk of sounding very very stupid:

In any population, spontaneous mutations in DNA arise through a variety of mechanisms, including chemical effects, random recombination and other unknown etiologies. While most of these mutations have little aparent effect, some provide a survival benefit on the individual (ie longer legs allow one organism to run faster and escape predators). Because those individuals of a given species that have a survival benefit are more likely to reproduce, those genes are more likely to become predominant in the population. Over time, the prevalent genes in a given population will undergo a shift which favors survival benefit in that population's particular ecosystem.

[Really Not All That Bright]

Actually, our *ahem* "learned companion" SW did raise an interesting point.

We can now map a human genome, so I presume we could map the genome of, say, a bacterium or amoeba or some other organism that can exist as a single cell.

Is there a reason why we couldn't synthesize a single-celled organism once we've mapped its genome?

If this is outside the scope of the thread I'll be happy to start a new one in GQ.

[CairoCarol]

Without reading any of the previous postings, here is what I think I know.

First, "theory" in this term means "an explanation for a process that is reasonably well understood and accepted as factually correct," like the "theory of gravity." It is NOT a theory in the sense of "an unproven idea that may be tossed out when new evidence comes to light."

The "theory of evolution" was developed by Charles Darwin decades before he published his thesis in "The Origin of Species." He did not publish until he got wind of the fact that someone else was about to publish the same ideas, and he wanted credit for his deductions. For years he did not publish both because he feared the backlash from religious society, and out of respect for his beloved wife, who was far more religious than he was.

Essentially the theory of evolution says that over time populations will adapt to their environment. Certain traits (let's say the ability to hide from predators) promote the ability to survive and individuals within a population that express those traits are more likely to pass them on through their genes to the next generation. There is nothing in the evolutionary process leading to an "ideal" or more "advanced" state - evolution simply leads to traits that enable survival in a particular ecological niche.

Anti-evolutionists sometimes ridicule the idea that evolution could lead to the complexity we see in life today, saying "what good is a half-evolved eye?" But they are overlooking how evolution works. For one thing, evolution has been going on for a helluva long time, so a complex result isn't really all that surprising. For another, because the evolutionary process is based on random mutation, the first recognizable "eye" may have been due to a mutation in a body part that was in use for something else or was simply harmless (evolution does nothing to get rid of characteristics that don't interfere with survival). Also, it isn't too incredible to imagine that some rudimentary cells became light-sensitive and this conferred an advantage, so the complex eye that we know today really could have evolved from an eyeless creature.

I know, or think I know, a lot more about evolutionary theory, but it is hard to summarize it in neat little paragraphs. Give me a multiple choice test on the subject, though, and I bet I'd score pretty well. I've read "Wonderful Life" and many other Steven Jay Gould books -- Ask me about punctuated equilibrium and the Burgess Shale! (I've read Dawkins, too.)

I also know a bit about the personal history of Darwin. He was NOT the naturalist on the Beagle, he was a "gentleman's companion" for the captain. Also, he came up with an explanation for the formation of atolls at a time when our ability to gather evidence on the subject was too rudimentary to prove or disprove his ideas. Since then, modern science has shown that he was indeed correct, and his insight into atoll formulation is considered one of the finest examples of pure deductive reasoning known in the world of science.

[MrDibble]

The idea was to elicit mistaken impressions so that others might correct them.
In that vein - I think a lot of people are under the impression that natural selection is the be-all and end-all of evolution methods, thereby discounting genetic drift, which, depending on population size, can be even more important.

[MrDibble]

Actually, our *ahem* "learned companion" SW did raise an interesting point.

We can now map a human genome, so I presume we could map the genome of, say, a bacterium or amoeba or some other organism that can exist as a single cell.

Is there a reason why we couldn't synthesize a single-celled organism once we've mapped its genome?
We're not advanced enough yet?

We have (http://en.wikipedia.org/wiki/List_of_sequenced_bacterial_genomes) mapped (http://en.wikipedia.org/wiki/List_of_sequenced_eukaryotic_genomes) out (http://en.wikipedia.org/wiki/List_of_sequenced_archeal_genomes) the genomes of some simpler organisms (this is not as trivial as you'd think - the largest bacterial genome is something like 10 million base pairs vs humanity's 3.2 billion, the largest protist one has 670 billion).

Plainly put - DNA is not an instructional manual for human consumption. It's more of a recipe book to be read by the machinery of a cell. IOW - you need a working cell to use DNA to make more cells, plain as that. We can already do this, tweaking DNA (http://en.wikipedia.org/wiki/Transgenic_bacteria) to get bacteria to produce new and unique bacteria. And one day we will have the nano-assembly capability to generate a new cell with non-cellular assemblers (why we'd want to is a different debate), but we're not there yet.

[Superfluous Parentheses]

At the risk of sounding very very stupid:

In any population, spontaneous mutations in DNA arise through a variety of mechanisms, including chemical effects, random recombination and other unknown etiologies. While most of these mutations have little aparent effect, some provide a survival benefit on the individual (ie longer legs allow one organism to run faster and escape predators). Because those individuals of a given species that have a survival benefit are more likely to reproduce, those genes are more likely to become predominant in the population. Over time, the prevalent genes in a given population will undergo a shift which favors survival benefit in that population's particular ecosystem.

This is all all think correct, but there's one important thing missing: in organisms that have some way of combining genetic information from different individuals (sexual reproduction being one popular mechanism) most of the variation between inviduals is due to that mixing (you'd still need some mutations to get new gene variants, though).

[Sr Siete]

It was supposed to be David Duchovny's breakthrough movie, but he didn't take. I think it was directed by the Ghostbusters guy. The premise was interesting, ut it couldn't focus between being a zany comedy or a sci-fi flic, and it appeared just when audiences were getting tired and over saturated with cgi.

Decent timewaster, but not for repeated viewing.

[capeo]

Actually, our *ahem* "learned companion" SW did raise an interesting point.

We can now map a human genome, so I presume we could map the genome of, say, a bacterium or amoeba or some other organism that can exist as a single cell.

Is there a reason why we couldn't synthesize a single-celled organism once we've mapped its genome?

If this is outside the scope of the thread I'll be happy to start a new one in GQ.

There's no reason we couldn't but right now we are simply not capable. It's an extraordinarily complex undertaking to synthesize then piece together that much DNA. Not to mention a living cell is far more than DNA. It's RNA and organelles and cell walls, etc. As it is, the best we've done is insert small strands of synthesized DNA into fatty membranes in an attempt to make a protocell. Basically the simplest self replicating unit we can devise and something that could have occurred naturally in early shallow oceans. The guys at Harvard can explain this much better than myself:

http://origins.harvard.edu/

[Really Not All That Bright]

Thanks. That's exactly what I was looking for - whether limitations on current technology prevented it.

[TimeWinder]

Is there a reason why we couldn't synthesize a single-celled organism once we've mapped its genome?

This isn't a problem just for living things; we can't synthesize most systems of complex molecules. We think of synthesis as taking a box of various elements' atoms and putting them together like itsy-bitsy tinkertoys. But we don't have the technology to do that at any sort of scale. We can create large quantities of molecules that are the product of various chemical reactions (say, dumping chlorine and sodium together in water to get a lot of salt in solution), but slapping together multiple end products at once without undesirable side products....nope, not yet.

On the plus side: if we ever get this, Star Trek-style replicators will be right around the corner. And there's no reason to think that such a device, if we had one, could not produce a living cell (given an atomic or molecular-level mapping, not just the gene sequence). Matter is matter.

[Skald the Rhymer]

In that vein - I think a lot of people are under the impression that natural selection is the be-all and end-all of evolution methods, thereby discounting genetic drift, which, depending on population size, can be even more important.

If only someone would write a few paragraphs on the subject. I would but unfortunately I don't know how to use the Internet.

[Really Not All That Bright]

On the plus side: if we ever get this, Star Trek-style replicators will be right around the corner. And there's no reason to think that such a device, if we had one, could not produce a living cell (given an atomic or molecular-level mapping, not just the gene sequence). Matter is matter.
Well, not quite. A dead cell is chemically identical to a living cell, except that it's dead, no?

[TimeWinder]

Well, not quite. A dead cell is chemically identical to a living cell, except that it's dead, no?

No. Some sort of damage (physical change) caused it to be dead. At the risk of an unsupportable claim, I doubt there's a mystical "cell soul" that makes them alive. Electrical activity is going to be the fudge point here, but I don't think I'd claim that a cell that could be restored to life with a little electrical charge was really "dead."

But your point is a good one nevertheless, and probably a more salient answer to the "why can't we make one" answer than mine: the fact that we can't synthesize a live cell is much less remarkable when you realize that we can't synthesize a dead one, either.

[Galwegian]

Okay, without looking at anything other than the OP:

Because each organism is different, there will be certain individuals who are more likely to survive than others for a given set of circumstances: they may be stronger, faster, better at hiding, or more resistant to dehydration, cold, heat or any number of other adverse factors. Those that are more likely to survive to the point of reproduction, are likely to pass on the genes that code for their enhanced likelihood of survival to their offspring. Over many generations, this process of natural selection has a very gradual tendency to adapt organisms to their environment.

Over a long period of time, the organisms that have adapted resemble their ancestors less and less, and diverge into different species, that because of the changes in their genetic makeup can no longer interbreed.

There’s other stuff about mutations and asexual versus sexual reproduction, but that’s the very bare bones of it.

[Really Not All That Bright]

But your point is a good one nevertheless, and probably a more salient answer to the "why can't we make one" answer than mine: the fact that we can't synthesize a live cell is much less remarkable when you realize that we can't synthesize a dead one, either.
:D

[Voyager]

Thanks. That's exactly what I was looking for - whether limitations on current technology prevented it.

However we can synthesize viruses. In the Times Science Section today there is a fascinating story about fossil viruses that get lodged into our DNA, from invading our egg and sperm cells and thus getting reproduced along with the rest. Mutations prevent it from replicating on its own. However, scientists have gotten different versions, used textual analysis to find the original one, and synthesized the original virus - which can replicate.

That's why I asked SW if he considered viruses as being alive. If you do, we have already created life from scratch.

[MrDibble]

If only someone would write a few paragraphs on the subject. I would but unfortunately I don't know how to use the Internet.

Basically, natural variation and the effect of random decisions of what to pass to each offspring mean that some traits can be fixed (be the only variant found in a population - say, only blue eyes) or in the opposite way, eliminated entirely (no gene for blue eyes). This can occur without any selection pressure at all, just by random sorting, and much more so in smaller populations (so-called genetic bottlenecks)

The classic analogy is you have a bag of 20 black marbles and 20 white ones. You choose them randomly, and for each one, you put a marble from a large pile of that colour in a second bag, until you have 20 marbles there. Then choose randomly from that bag and put into a third. How many iterations before you only have a bag of one colour to choose from? What if you have 2 marbles in the first bag? or 2000 000? Now think of the marbles as population size, and the colours as traits they possess. That's genetic drift in a nutshell

[Darwin's Finch]

And a subclass of genetic drift is the Founder Effect, wherein a small population moving into a new environment (or otherwise cut off from its parent population such that gene flow has been eliminated) will have reduced genetic diversity. This will result in a population that can be quite distinctive from the parent population after a relatively short time, and is a major component of peripatric speciation.

[Malleus, Incus, Stapes!]

This is probably pretty simplistic, but:

Cells mutate. If the right cell mutate (it has to be the germ cells, I think), the change in physiology will be passed down to the next generation. "Good" mutations help the organism survive and mate. If the organism can do those things better than its fellows, it will have more offspring.

Most mutations either have no discernible effect, or a minor one, or are deleterious to the organism. Usually, you'll end up with a gene pool that has slight variations. This frog tolerates cold weather, this frog tolerates warm weather. It's been a particularly hot summer, so the warm-loving frogs will leave more tadpoles. There will still be a few cold-lovers, and if there's a cold year the warm-frogs will do poorly and the cold-frogs will thrive. If there's a major environmental change- global warming wipes out winter- the genes for warmer and warmer temperatures will dominate, until your coldest-weather frog will still like warmer temperatures than its heat-loving ancestors.

[RickJay]

This thread is past 100 posts and I've no idea what state it's now in but I'm going to answer the OP literally, explaining evolution as far as I understand it without using any cite or source of any kind as I type this. I'm guessing at least one creationist poster has turned it into a trainwreck but i'm going to be sincere.

Evolution is the process whereby the characteristics of living organisms change over the course of multiple generations or the reproduction of the organism. As organisms reproduce, they change in slight ways which, over the course of time, accumulate into substantial changes, even resulting in the creation of entirely new species.

Evolution occurs primarily through mutations in the genetic code of an organism, a process which can happen in any number of ways; random change, exposure to chemicals, exposure to radiation, disease, and so on. While such mutations are random and most are irrelevant, those which happen to have a positive impact on the organism's likelihood of successful reproduction will result in that mutation being more likely to be passed on to more organisms, a process commonly referred to as "natural selection." Over time a sufficient number of such mutations can cause such substantial changes that the organism is so different from its ancestors that it constitutes a new species.

Species of organism do not necessarily evolve to become more complex or "better" organisms; any mutation that helps reproduction and survival will be selected for. However, the sheer scope and volume of living creatures in the world has resulted in a very great number of complex species evolving into existence.

[tdn]

Cells mutate.

I think that this is incorrect. It's not the cells that mutate, it's the genes that do.

That brings up an interesting question, though. Is the mutation carried in just one sperm (or egg), or all of them?

[Chronos]

Evolution, in its broadest sense, is a change over time of the properties of a system based on previous properties of the system and on the external environment.

In a biological context, evolution refers to the changes in populations of living organisms based on the premises that, first, there will be some variation in traits of the population, second, that the traits of offspring will be significantly correlated to those of their parent or parents, and third, that some traits or combinations of traits will provide an organism with an advantage in the task of producing offspring. Those traits which lead to their carriers producing more offspring will gradually become more prevalent in the population of organisms, which can eventually result in extremely large changes.

[Bryan Ekers]

Well, not quite. A dead cell is chemically identical to a living cell, except that it's dead, no?

Well, they both have the same number of particles.


Now excuse me, I'm leaving this thread for one less complicated.

[psychobunny]

Originally Posted by psychobunny
At the risk of sounding very very stupid:

In any population, spontaneous mutations in DNA arise through a variety of mechanisms, including chemical effects, random recombination and other unknown etiologies. While most of these mutations have little aparent effect, some provide a survival benefit on the individual (ie longer legs allow one organism to run faster and escape predators). Because those individuals of a given species that have a survival benefit are more likely to reproduce, those genes are more likely to become predominant in the population. Over time, the prevalent genes in a given population will undergo a shift which favors survival benefit in that population's particular ecosystem.

This is all all think correct, but there's one important thing missing: in organisms that have some way of combining genetic information from different individuals (sexual reproduction being one popular mechanism) most of the variation between inviduals is due to that mixing (you'd still need some mutations to get new gene variants, though).

Sorry I wasn't more clear-the combining of information from different individuals was what I referred to as "random recombination" ie meiosis, followed by sexual reproduction.


By the way, an additional evolution question about life. If it "just happens" why can't you heat a cell till it just barely dies, but is not damaged physically and then go back to the room temperature with food all around it and have it just come back to life? I mean everything is all built so why isn't it alive again? This assumes the cell is totally dead now, not just in a suspended state. Wouldn't evolution theory say the cell ought to become alive again?

Without trying to maintain any hijack of this thread, I was struck by the similarity of the above experiment to the initial cloning that produced Dolly the sheep. To simplify greatly, a cell whose nucleus was removed (and is therefore incapable of reproduction and arguably irredeemably damaged) was injected with a nucleus from a separate cell (also incapable of sustaining itself or reproducing). Through the application of electricity, both of these essentially nonviable components were stimulated to produce a cell capable of reproduction and differentiation, which I would argue basically is doing what is discussed in the quote above.

[Taber]

Rumor has it that this thread got hijacked, but I am playing along with the rules in the OP, so I haven't read the thread yet.

Evolution is the process by which species change over generations, sometimes branching off into different species. The main driver for evolution is natural selection. Genes combine differently, and sometimes mutate. Natural selection occurs when the new combinations/mutations cause the animal with the new genes to be more or less successful at reproducing. If the new genes are harmful, then the new genes will likely die off. If the new genes are helpful, they will likely propagate over time, either replacing the old genes, or creating two different types if both the new genes and old genes have a niche.

[Superfluous Parentheses]

Sorry I wasn't more clear-the combining of information from different individuals was what I referred to as "random recombination" ie meiosis, followed by sexual reproduction.
Ah yes. Sorry I missed that.

[Der Trihs]

Evolution is the inevitable process resulting when you have variable inheritance, and something that causes some variants of whatever type of inheritance is involved ( genes in Earth biology, of course ) to reproduce better. Natural selection, sexual selection, some guy trying to breed a better herd dog; it's all evolution, just with different selection criteria.

I would also call what happens to many forms of information and ideas evolution; some spread and reproduce - in human minds, or human records - because they appeal better to human instincts or a human culture; others don't appeal to or interest us, don't reproduce and therefore languish or die out. This is closer to Lamarkian evolution than the Darwinian style Earth biology uses though.

Darwinian evolution refers to the type of evolution seen in the biology of Earth. Different genes are reproduced with greater or lesser frequency due to how they affect their host creature, and the ones that do so in a way that increases their chance of reproduction spread more. There is no foresight, no plan; only the end results of interactions with the environment ( which from a gene's "point of view", includes its host creature and other genes ). Being mindless, the genes are "selfish"; they are selected for according to what has benefited their reproduction and nothing else. While genes do cooperate, it is only because they have evolved such cooperation because it has in the past furthered their selfish replication.

The variation in genes that allows for such selection has several sources. Mutation being well known but actually minor. Genes imported from outside the species by retroviruses; something like 2 percent in humans IIRC. Recombination; where existing genes are reshuffled to produce a new combination of time tested genes; allowing variability without the outright randomness of mutation.

[Beware of Doug]

Evolution is a theory stating that organisms change to adapt to their environment. This happens by mutation, which introduces the changes, reproduction, which perpetuates them if adaptive, and attrition, which does not allow them to perpetuate if not adaptive.

Some people are pissed about evolution because they want to believe that
a. God created the universe in seven days or in 4004 BC or somesuch;
b. if we are the descendants of poo-throwing simians and/or share 90% of our DNA with flies, who eat poo, that somehow or another argues against the existence of a God.

A splinter group of "some people" believes in intelligent design, which is that evolution was shaped by God and, moreover, that this can be logically "proven."

The end. Not.

[cerberus]

There's a certain "stable" set of alleles in play, as well as transient alleles due to mutation.

The alleles are propagated by individuals who survive long enough to pass said alleles along to their offspring, who then repeat the process.

Species are basically clusters of individuals sharing sets of core alleles and are linked by breeding relationships.

[RaftPeople]

Evolution is the small changes that God causes so that organisms adapt to their environment without becoming new species.

[Superfluous Parentheses]

Evolution is the small changes that God causes so that organisms adapt to their environment without becoming new species.

Ooh, good answer.

[Cesario]

The theory of natural selection was proposed by Charles Darwin, and presented to the public and the scientific community through his book "Origin of the Species".

The process outlined by Darwin came in 3 steps:

1) Overpopulation - A population of creatures grows larger than the environment can sustain.

2) Variation - Within the population there are differences between individuals.

3) Selection - Because the environment is overpopulated, members of the species compeete with one another for scarce resources, and the ones who are better suited (due to the traits described in step 2) survive to sire the next generation.

The survivors of this process posess traits which are better suited to surviving in the environment than the ones who died off, and pass these better traits on to their ofspring. When this process takes place repeatedly over millions of years (with some members of the population becoming isolated from one another), the accumulated changes can result in different groups of descendents of the original population no longer having enough in common to produce viable ofspring, and thus we have speciation.

A concern Darwin had, and which was pounced on immediately by his critics was the question of how small, accumulated changes could add up into some of the more complex structures observed in nature. While it makes obvious sense that an eye would confer a terrific advantage, this was clearly too complex a structure to just pop into being as a result of the normal variation between individuals. Further, the various steps towards getting a functional eye would include individuals who could not actually see, and would thus gain no survival advantage from the precursor trait. Eventually, scientists determined a set of steps wherein the precursor traits to the eye could provide a meaningful survival advantage (starting with a photosensitive set of cells on the surface, moving on to protecting that photosensitive area by recessing it, then shrinking the opening of the cavity for additional precision and focus, followed by a transparent covering for the cavity, followed by that covering developing into a lense, and eventually we have an eye).

During Darwin's time, gene theory had not yet been developed, so the mechanism of inheritable traits that would vary between individuals was not yet understood. It was only significantly later that the discovery of DNA allowed scientists to pin the heritability concept as being due to this molecule.

With the development of gene theory, it became understood that the variation Darwin talked about in his second step was a result of mutations within the DNA. These mutations, if harmful, made an individual less likely to survive and reproduce, and thus the harmful mutations tended to die out. If the mutations proved beneficial, the individual was more likely to survive and reproduce, and thus beneficial mutations tended to spread.

Darwin's concept of natural selection compeeted with the theory of Lamarkian evolution, which presumed that instead of just inherent traits, aquired traits could also be passed down from parent to child. This has largely gone out of vogue, though in certain traits, it is possible, for example the ability of mothers to pass on antibodies to their ofspring.

Sexual reproduction is a kind of meta-advantage in the constant war for surival, in that it serves to increase the ammount of variation between individuals in a sexually compatible population. As a result, such species "evolve" faster. This is particularly necessary in complex species since, due to the high number of genes, mutations that would have a major impact on a simpler creature (like an ameba) hardly impact a more complex species. A species that adapted to its environment too slowly would be at the mercy of changing environmental factors, and thus might die out entirely.

Artificial, rather than natural selection is a process whereby an intelligent designer such as humans, carefully controls the breeding of a species in order to produce a desired end result. One advantage of this form of slection is that the patron species can prevent a harmful intermediate step in the development of a beneficial trait from resulting in the extinction of the line before that trait can develop. Another advantage is that the intelligent species does not need to wait for population pressures to shift the ratios of traits, and can instead directly breed for the traits they desire.

A common misconception of the concept of evolution is that it declares that man evolved from apes or monkeys. This is not strictly the case as no modern species is the ancestor of modern man. Instead, the theory states that humans and modern primates share a common ancestor population, which branched into multiple species including modern apes, and modern humans.

The theory of evolution says nothing about the origin of life as a whole, merely how the incredible complexity and diversity of species came to exist after the creation of life. Abiogenesis, a different theory, posits that life arose out of nonliving chemicals.

[Darwin's Finch]

A common misconception of the concept of evolution is that it declares that man evolved from apes or monkeys. This is not strictly the case as no modern species is the ancestor of modern man. Instead, the theory states that humans and modern primates share a common ancestor population, which branched into multiple species including modern apes, and modern humans.

This is a taxonomic issue, rather than a strictly evolutionary one. The current trend is to group organisms into monophyletic clades - that is, a group of populations or species that all evolved from a common ancestor. Since the most recent common ancestor of extant apes and humans was an ape, we inherit the moniker and are ourselves apes.

Just because our ancestors are extinct doesn't mean they weren't also apes.

[AHunter3]

Is there a backstory behind the original post? Or just as stated, "seeing what people hereabouts know about evolutionary theory"? if the latter... how're we doing?

[Irishman]

Following the OP, only reading the OP, first post:

I don't really know where to begin, or how deep to get. Basically (how many people have said that yet?), the Theory of Evolution is about how the variety and diversity of life accummulated on this planet. It says that individual organisms have minute variations in form, and that through reproduction, those variations can accumulate in such a way that descendents can take on changes from their ancestors. Through the mechanism of many generations and lots of time, accummulated changes can shift from small to larger changes.

Evolution doesn't really address how life first formed. However, embedded within the assumptions of evolution is that we can understand and describe the processes involved. Some people use this to draw conclusions about metaphysical and philosophical questions. Strictly speaking, Evolution doesn't address those questions. The ability to understand those processes, though, does inform some assumptions made in those discussions and does affect the likelihood of some conclusions.

Evolution relies upon the mechanism of life itself - the genetic code that contains the instructions for how to build an organism. Reproduction of the organism relies on reproduction of the genetic code. How that code reproduces allows for changes in a couple ways. One is simple mutation - some environmental effect (chemical, radiation, etc) changes one of the chemical structures of the genetic code, which changes how that part of the code behaves, and that leads to a difference in the offspring from the parent. A second mechanism occurs in some types of organisms that rely on two parents instead of one to contribute genes. That kind of reproduction introduces changes by mixing contributions from two sources in different ways, which makes more variety possible.

The second factor that is critical to evolution is the environment - and by that I mean any and all conditions in which the organism must survive. Everything about that environment provides possible ways the organism could die, and therefore not reproduce, but by reproducing, it passes on its genetic material, and therefore the "species" continues. Each individual of that species finds itself with the same needs and the same controls it must overcome (i.e. predators, dangers, etc). But each individual is slightly different, due to those variations mentioned above. Ergo, some individuals are better suited to surviving particular dangers. Some find food better. Some avoid predators better. Some reproduce more, and thereby pass along more surviving offspring even if the individual itself dies.

Because of this, those sets of genes more suited to the particular environmental conditions are more likely to pass along, and those less suited are more likely to be eliminated. Variations accumulate, and the environmental controls provide a sense of direction to the changes. Things that help overcome dangers accummulate, things that make you more susceptible get eliminated. Neutral things can float along in the population because they are not actively eliminated.

Somehow the first living organism developed. Evolution doesn't directly address this. But once this first organism developed and began reproducing, it began filling its environment to the fullest ability. The resources available made more organisms possible, which spread more and more. Eventually, organisms became dispersed enough to face different specific environments. And also, organisms changed their environments. Therefore, there did not remain one population of organisms that remained the same, but rather various different types that began to change in different ways to use different resources and have different strategies for surviving the challenges.

Over vast amounts of time, organism structures became more complex. Single-celled organisms became either symbiotic (e.g. mitochondria), or else collaborative and formed multicellular organisms. These became more complex, and differentiation of function occurred within these complex organisms, and the first plants and animals formed.

Continued adaptation, environmental changes, and deep time drove more and more changes, which created more and more diverse organisms, and spread them globally. Eventually, this process lead to the conditions of life on Earth today.

Is that what you're looking for?

[Skald the Rhymer]

Is there a backstory behind the original post? Or just as stated, "seeing what people hereabouts know about evolutionary theory"? if the latter... how're we doing?

My idea in starting this thread was to elicit misconceptions about evolution so that they could be corrected, and in the process start a discussion or debate on the subject. I thought an interesting way to do this would be to get people to say what they think, in as much detail as they felt comffortable with, on the theory that unless Richard Dawkins is secretly a Doper, any person who did so would have at least one thing wrong. (I forgot to mention genetic drift, for instance.)

[Darwin's Finch]

While perhaps not a misconception, it does seem that most folks' understanding of evolution begins and ends with natural selection (with some basic genetics thrown in). A pity, really, since there's a heck of a lot more to it than that.

[Skald the Rhymer]

While perhaps not a misconception, it does seem that most folks' understanding of evolution begins and ends with natural selection (with some basic genetics thrown in). A pity, really, since there's a heck of a lot more to it than that.

How is it not a misconception that many persons think evolution begins & ends with natural section? That's like thinking that the laws of motion begin & end with "For every action, there is an equal and opposite reaction." In fact it's worse, given the fact that many persons also think that "survival of the fittest" means "organisms always get bigger, stronger, and meaner over time."

[Darwin's Finch]

How is it not a misconception that many persons think evolution begins & ends with natural section? That's like thinking that the laws of motion begin & end with "For every action, there is an equal and opposite reaction." In fact it's worse, given the fact that many persons also think that "survival of the fittest" means "organisms always get bigger, stronger, and meaner over time."

Note that I said "does seem that". That's because I can't be sure that the previous posters who only made mention of natural selection in their brief summaries really believe that that's all there is to it. I suspect that most folks get that there's more to it, but the "more" typically isn't expounded upon in popular literature, or in basic high school or college-level courses.

If folks do believe that NS is evolution, and evolution is NS, then yes, that's a misconception.

[RickJay]

Note that I said "does seem that". That's because I can't be sure that the previous posters who only made mention of natural selection in their brief summaries really believe that that's all there is to it. I suspect that most folks get that there's more to it, but the "more" typically isn't expounded upon in popular literature, or in basic high school or college-level courses.

If folks do believe that NS is evolution, and evolution is NS, then yes, that's a misconception.
It's a mild misconception, but do you really think it's a pity that not everyone's a subject matter expert in your field of interest?

Reading the thread, I think people have a decent handle on the basics. I know people who thought the phases of the moon are caused by the Earth's shadow, so it could be a lot worse.

[Darwin's Finch]

It's a mild misconception, but do you really think it's a pity that not everyone's a subject matter expert in your field of interest?


Relax, it's a turn of phrase, nothing more. I do not pity anyone in this thread, nor do I find anything about the posters pitiful.

[Skald the Rhymer]

Relax, it's a turn of phrase, nothing more. I do not pity anyone in this thread, nor do I find anything about the posters pitiful.

I always figured you pitied me my lack of rhythm. It hurts that you don't.:(

[Irishman]

CairoCarol, said:
The "theory of evolution" was developed by Charles Darwin decades before he published his thesis in "The Origin of Species." He did not publish until he got wind of the fact that someone else was about to publish the same ideas, and he wanted credit for his deductions. For years he did not publish both because he feared the backlash from religious society, and out of respect for his beloved wife, who was far more religious than he was.

To be fair, he developed the theory over time, and didn't trust it at first so wanted to gather as much evidence along many different lines as possible. But largely he was cognizant of the religious affect and his own wife's beliefs.

Really Not All That Bright said:
Well, not quite. A dead cell is chemically identical to a living cell, except that it's dead, no?

I would say no, there is something different in the chemistry. It's like the difference between a car with the engine off and a car with the engine on - they are both cars, but only one can take you somewhere.

tdn said:
That brings up an interesting question, though. Is the mutation carried in just one sperm (or egg), or all of them?

That depends. It is possible for the mutation to occur in the sperm creating cell's DNA, which then affects all sperm it creates. Or it can just be in a sperm cell.

Cesario said:
1) Overpopulation - A population of creatures grows larger than the environment can sustain.

Technically, I don't think overpopulation is required. I mean, predators are part of the environment, no? So keeping the population stable by killing off a certain percentage of every generation is still the environment sustaining the population. Right?

The limiting factor is that dangers exist for the population - whether that is a limit on particular resources or external threats like predators or weather and terrain. Those dangers create situations where individuals within the population are in competition with each other.

A common misconception of the concept of evolution is that it declares that man evolved from apes or monkeys.


Darwin's Finch said:
This is a taxonomic issue, rather than a strictly evolutionary one. The current trend is to group organisms into monophyletic clades - that is, a group of populations or species that all evolved from a common ancestor. Since the most recent common ancestor of extant apes and humans was an ape, we inherit the moniker and are ourselves apes.

The question is what Cesario meant by "apes". I think he meant modern great apes, i.e. gorillas, chimpanzees, bonobos, or orangutans. His point was valid for that. However, "apes" is a group that is larger than just those modern exemplars, and includes humanity's common ancestors with each of those other species, as well as the line of humans since.

[ITR champion]

I thought about opening this thread in IMHO or MPSIMS, but if the thread gets any legs at all I'm sure a discussion will break out so I decided not to bother. I opened the thread here rather than in GQ because my primary interest is seeing what people hereabouts know about evolutionary theory. A couple of comments:


For obvious reasons, please don't go to talk.origins, Wikipedia, or any other reference sites until you have made your first response to the thread. In fact, if you could refrain from links and citations in your first response, that would be great.
Please also make your first response in the thread without reading other responses to the OP.
Once you're past your first entry, cite (and call for cites) to your heart's consent. Likewise, you may point out errors, misconceptions, incomplete ideas, and misleading statements in previous posts. Just try to leave your swords in their scabbards, revolvers in their holsters, and axes in whatever you store your axes in.


Go.
Posting what I know about the theory of evolution would take quite a while, since I've read dozens of books and hundreds of papers on the topic, but for a quick summary I know the following things.

1. Evolution is the process by which new physical traits are formed in an organism and, through the method of natural selection (also sexual selection to a lesser extent), certain traits spread while others are eliminated.

2. The only method by which new traits can form is by mutations in an organisms DNA during the process of DNA replication. Most DNA mutations cause no results at all, a few cause harm, a very few are beneficial.

The most common type is a point mutation, which can alter only one amino at a time. There are also other types of mutations, in which larger segments of the chromosome change.

In the past, scientists believe that the genome consisted of distinct genes, each responsible for a single trait. In recent years, they've discovered that the situation is more complicated. Multiple genes may contribute to one trait, multiple traits may be influenced by one gene, and regions of DNA formerly thought to be useless may play a role in gene expression.

3. Natural selection occurs by Darwin's six steps: organisms over-reproduce, not all organisms survive, variations exist, those variations are inherited, certain variations make an individual more fit, and as a result whole populations become more fit. Sexual selection occurs when a certain trait makes an individual more likely to mate and reproduce.

4. From the fossil record, scientists have deduced that organisms tend to go through long periods of relatively little change, interrupted by short periods of rapid change. This is called "punctuated equilibrium". The biggest period of chance was the Cambrian Explosion roughly 600 million years ago, when all the complex animal phyla appeared.

5. Some people believe that evolution cannot account for the presence of complex chemical systems involving tens or hundreds of proteins, wherein the removal of any one protein will make the entire system useless, the argument being that the odds of multiple proteins arising from mutation at the same time or too small. Others respond that such systems can arise one protein at a time, where earlier versions of the system played a different role.

6. Evolution is unrelated to questions of the origin of life and the origin of the universe, and despite the grandiose claims of some people, does not provide any evidence against the existence of God.

7. There have been many theories designed to justify certain statements about human behavior on evolutionary grounds, ranging from Darwin's early beliefs that certain races were inferior because they were less fully evolved up to current evolutionary psychology that seeks to explain the origin of current behaviors due to selection pressures in the pleistocene environment. Every single one of these theories has turned out to be false when put to experimental test.

[Superfluous Parentheses]

I always figured you pitied me my lack of rhythm. It hurts that you don't.:(

I always imagine your username to go along the lines of the Bob the Builder theme song (http://www.youtube.com/watch?v=bA16sqCusbY). :)

[Chronos]

I left a lot out of my answer since I wanted to be general about it. While modern terrestrial biology does explain the inheritance of traits in terms of DNA sequences re-mixed during mating through meiosis and the like, none of that is inherent to evolution. If we ever encounter alien life forms which show variation in their traits, and reproduce in such a way that the traits of their offspring are correlated with those of their parent(s), then we'll observe evolution among them, too, even if their genetic information is stored and transmitted in a completely different way than ours.

[Skald the Rhymer]

I always imagine your username to go along the lines of the Bob the Builder theme song (http://www.youtube.com/watch?v=bA16sqCusbY). :)

I'm just swamped with paperwork today, so I'm gonna need you to take vengeance upon yourself. I'm FedExing you the alligators.

[Cesario]

Cesario said:


Technically, I don't think overpopulation is required. I mean, predators are part of the environment, no? So keeping the population stable by killing off a certain percentage of every generation is still the environment sustaining the population. Right?

The limiting factor is that dangers exist for the population - whether that is a limit on particular resources or external threats like predators or weather and terrain. Those dangers create situations where individuals within the population are in competition with each other.

Yes, that would be reasonable. Natural consequence of trying to stuff a lifetime of education into a single forum post. These were the steps they explained to me in my earliest biology course, and obviously they were a simplification. I simply assumed that was the phrasing of the original theory due to the way it was presented.

Darwin's Finch said:


The question is what Cesario meant by "apes". I think he meant modern great apes, i.e. gorillas, chimpanzees, bonobos, or orangutans. His point was valid for that. However, "apes" is a group that is larger than just those modern exemplars, and includes humanity's common ancestors with each of those other species, as well as the line of humans since.
That's why I added the word "modern" before both humans and apes at the end of that section, since I realized that this might need additional clarification.

[Superfluous Parentheses]

That's why I added the word "modern" before both humans and apes at the end of that section, since I realized that this might need additional clarification.

Personally, I don't get what the problem is with stating that Humans evolved from monkeys or apes. Sure the actual monkeys/apes we evolved from are extinct today, but that doesn't mean that our ancestors weren't apes.

The only reason for this denial that I can see is that this fact is continuously misrepresented in the anti-evolutionary literature. As far as I can see the proper reaction should be to correct the factual errors, not to confuse matter further.

We are apes, and apes are monkeys. Going back further, matters get more confused, but that is purely due to our poor nomenclature - we're also mammals etc etc - just like birds appear to be a subset of dinosaurs. It's just that much of the intermediate groupings are poorly defined and/or don't actually exist except in our head. The common descent of our species all the way back to fish at least is pretty clear.

[Really Not All That Bright]

6. Evolution is unrelated to questions of the origin of life and the origin of the universe, and despite the grandiose claims of some people, does not provide any evidence against the existence of God.
The existence of a supreme being, perhaps not. The existence of the God of the Bible? Absolutely.

[Superfluous Parentheses]

The existence of a supreme being, perhaps not. The existence of the God of the Bible? Absolutely.

At the risk of being pedantic: that depends on how literally you take the bible.

[Cesario]

Personally, I don't get what the problem is with stating that Humans evolved from monkeys or apes. Sure the actual monkeys/apes we evolved from are extinct today, but that doesn't mean that our ancestors weren't apes.

The only reason for this denial that I can see is that this fact is continuously misrepresented in the anti-evolutionary literature. As far as I can see the proper reaction should be to correct the factual errors, not to confuse matter further.

We are apes, and apes are monkeys. Going back further, matters get more confused, but that is purely due to our poor nomenclature - we're also mammals etc etc - just like birds appear to be a subset of dinosaurs. It's just that much of the intermediate groupings are poorly defined and/or don't actually exist except in our head. The common descent of our species all the way back to fish at least is pretty clear.
Among the things I know about evolution is that this fact is continuously misrepresented in anti-evolutionary literature. That's why I included it.

[tomndebb]

TWEEEEEET!

The relationships between theology or religious beliefs and evolutionary theory are also not pertinent to this thread.

Open a new thread to hammer that out, (or hammer each other).


[ /Modding ]

[MrDibble]

We are apes, and apes are monkeys.
Apes are not monkeys. This is because "monkeys" are not a clade, but a paraphyletic taxon - defined as excluding apes, lemurs and other prosimians.

The best word to substitute there is "simians" - us, the other apes, monkeys, we are all simians.

[Darwin's Finch]

The best word to substitute there is "simians" - us, the other apes, monkeys, we are all simians.

Except for those silly tarsiers. They don't get to be in our club! Well, the simian one, anyway. They do get to be in the Haplorrhini club with us, though....

[MrDibble]

Except for those silly tarsiers. They don't get to be in our club! Well, the simian one, anyway. They do get to be in the Haplorrhini club with us, though....

Well, they're not monkeys, so serves them right. Damn coat-tail-hangers-on, they should go join the prosimians where they belong...

[King Julian from Madagascar] ...the sexy, sexy prosimians. [/KJfM]

[Irishman]

Cesario said:
These were the steps they explained to me in my earliest biology course, and obviously they were a simplification. I simply assumed that was the phrasing of the original theory due to the way it was presented.

ITR champion said:
3. Natural selection occurs by Darwin's six steps: organisms over-reproduce, not all organisms survive, variations exist, those variations are inherited, certain variations make an individual more fit, and as a result whole populations become more fit. Sexual selection occurs when a certain trait makes an individual more likely to mate and reproduce.

You appear to be correct. I suppose I quibble over what is meant by "over reproduce"? Create more offspring than the number of parents (i.e. more than one offspring per parent per lifetime)? Creating more offspring than the environmental resources can support if they all survived to adulthood? Creating enough offspring that the population increases even after all limits (e.g. predation) are taken into consideration?

Superfluous Parentheses said:
We are apes, and apes are monkeys. Going back further, matters get more confused, but that is purely due to our poor nomenclature - we're also mammals etc etc - just like birds appear to be a subset of dinosaurs. It's just that much of the intermediate groupings are poorly defined and/or don't actually exist except in our head. The common descent of our species all the way back to fish at least is pretty clear.

This is perhaps a layperson vs. specialist thing, but humans are not fish, even though we are descended from fish. So why are birds dinosaurs just because they descended from dinosaurs?

[Chronos]

I'm not sure what the value is in considering the label "monkey" to apply to a paraphyletic taxon. If you get down into the technical details, then it's simpler to deal with the clades, so it'd be preferable to consider the clade of (common ancestor of old-world and new-world monkeys and all of its descendants), rather than the taxon consisting of that clade less the great apes. And if you don't get down to the technical details, the common usage is to consider apes to be monkeys. There's only a narrow layer of pedantry, insufficiently technical to prefer the cladistic view but insufficiently common to accept the common view, that maintains that the term "monkey" should exclude apes.

[Skald the Rhymer]

This is perhaps a layperson vs. specialist thing, but humans are not fish, even though we are descended from fish. So why are birds dinosaurs just because they descended from dinosaurs?

I think the wikipedia article on paraphyly (http://en.wikipedia.org/wiki/Paraphyly)may help. Also the one on cladistics (http://en.wikipedia.org/wiki/Cladistics). I would try to summarize but I have not yet convinced myself that my understanding is sufficiently rigorous.

[Darwin's Finch]

Cesario said:
These were the steps they explained to me in my earliest biology course, and obviously they were a simplification. I simply assumed that was the phrasing of the original theory due to the way it was presented.


ITR champion said:
3. Natural selection occurs by Darwin's six steps: organisms over-reproduce, not all organisms survive, variations exist, those variations are inherited, certain variations make an individual more fit, and as a result whole populations become more fit. Sexual selection occurs when a certain trait makes an individual more likely to mate and reproduce.

You appear to be correct. I suppose I quibble over what is meant by "over reproduce"? Create more offspring than the number of parents (i.e. more than one offspring per parent per lifetime)? Creating more offspring than the environmental resources can support if they all survived to adulthood? Creating enough offspring that the population increases even after all limits (e.g. predation) are taken into consideration?



What Darwin actually said was this:

A struggle for existence inevitably follows from the high rate at which all organic beings tend to increase. Every being, which during its natural lifetime produces several eggs or seeds, must suffer destruction during some period of its life, and during some season or occasional year, otherwise, on the principle of geometrical increase, its numbers would quickly become so inordinately great that no country could support the product. Hence, as more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life. It is the doctrine of Malthus applied with manifold force to the whole animal and vegetable kingdoms; for in this case there can be no artificial increase of food, and no prudential restraint from marriage. Although some species may be now increasing, more or less rapidly, in numbers, all cannot do so, for the world would not hold them.

So, it's not really the case that organisms over-reproduce, but rather if every individual grew to adulthood, the resulting population would be unsustainable. However, they do not all reach adulthood, because there is competition between the offspring and their siblings, conspecifics, or neighboring species (and even with "the physical conditions of life") to actually obtain the resources necessary to do. So the "over-reproduction" is with respect to the finite resources available in a given place and time, rather than a raw number.



Superfluous Parentheses said:
We are apes, and apes are monkeys. Going back further, matters get more confused, but that is purely due to our poor nomenclature - we're also mammals etc etc - just like birds appear to be a subset of dinosaurs. It's just that much of the intermediate groupings are poorly defined and/or don't actually exist except in our head. The common descent of our species all the way back to fish at least is pretty clear.


This is perhaps a layperson vs. specialist thing, but humans are not fish, even though we are descended from fish. So why are birds dinosaurs just because they descended from dinosaurs?

From a strict cladist viewpoint, humans are, indeed, fish (specifically, sarcopterygian fish). Birds are, too. Humans are primates < mammals < synapsids < amniotes < tetrapods < sarcopterygians < osteichthyes. Birds are theropods < saurischians < dinosaurs < archosaurs < reptiles < synapsids < amniotes < tetrapods < sarcopterygians < osteichthyes (with several other important branches omitted in both cases, of course). Basically, you can't say anything about sarcopterygian fish (or the more general category of osteichthyes) that doesn't also pertain to humans or birds, because we all share uniting characteristics (which, of course, is a product of our common ancestry).

[Darwin's Finch]

Birds are theropods < saurischians < dinosaurs < archosaurs < reptiles < synapsids < amniotes < tetrapods < sarcopterygians < osteichthyes

Uh...birds are sauropsids, not synapsids. Sorry about that.

[Rick]

I look at it from the practical view point.
When penicillin first came out it was a wonder drug against all forms of disease. As the years have gone by, it has lost its effect on may of these diseases. Syphilis is one example of this. There are some syphilis infections that are resistant to penicillin.
The penicillin is the same, so the disease must have changed. How did it change if not for evolution?
Same applies for TB and a number of other diseases.

[MrDibble]

I'm not sure what the value is in considering the label "monkey" to apply to a paraphyletic taxon. If you get down into the technical details, then it's simpler to deal with the clades, so it'd be preferable to consider the clade of (common ancestor of old-world and new-world monkeys and all of its descendants), rather than the taxon consisting of that clade less the great apes. And if you don't get down to the technical details, the common usage is to consider apes to be monkeys. There's only a narrow layer of pedantry, insufficiently technical to prefer the cladistic view but insufficiently common to accept the common view, that maintains that the term "monkey" should exclude apes.

So you're in favour of redefining "monkey" to be synonymous with the clade "simian" - it's a valid point of view, I can respect it, even if I don't agree that it should be so or that it is, in fact, the "common view" of sufficiently educated people - my 5 YO can easily tell you the difference between monkeys and apes ("only monkeys have tails, silly:rolleyes:"*). I'm OK with the existence of paraphyletic taxons for everyday descriptions - like the common use of "reptiles" which excludes "birds", or the taxon "algae" which jumps whole kingdoms.

ETA: that would be her rolling her eyes at me, not me at you.

[MrDibble]

From a strict cladist viewpoint, humans are, indeed, fish (specifically, sarcopterygian fish).
I'd take issue with this - from a strict view, humans are class Sarcopterygii (and superclass Osteichthyes), but they are not fish, because "fish" is not a clade, but a paraphyletic group.

[Darwin's Finch]

I'd take issue with this - from a strict view, humans are class Sarcopterygii (and superclass Osteichthyes), but they are not fish, because "fish" is not a clade, but a paraphyletic group.

I think you mean polyphyletic. "Fish" isn't a clade, but "sarcopterygian fish" can definitely be considered a clade (indeed, Sarcopterygii is typically referred to as "fleshy-finned fishes", vs. the "ray-finned fishes" which make up Actinopterygii). "Fish", taken by itself, however, is polyphyletic, since it's basically a haphazard grouping of all "swimmy things with fins", which includes everything from early vertebrates to gnathostomes to chondrichthyes, and the more traditionally-fishy teleosts, while excluding several other related groups.

So sure, there's no actual "fish" clade, but there are "fleshy-finned fish" and "ray-finned fish", just as there's no actual "monkey" clade, yet there are "new world monkeys" (Platyrrhini) and "old world monkeys" (Cercopithecidae).

And I'm surprised that you use both clades and Linnaean ranks, to be honest....

[MrDibble]

I think you mean polyphyletic.
Nope, I mean paraphyletic, as I understand it viz. a group that contains all "fish" up to their last common ancestor also contains things that are not "fish" viz. all the tetrapods. But that last common ancestor was probably a fish, too (i.e. a swimmy finned thing).
For it to be polyphyletic, it'd have to exclude the ancestor and be a wholly artificial grouping (like grouping birds, pterosaurs and bats together as "flyers" when their last common ancestor was not a "flyer").
"Fish" isn't a clade, but "sarcopterygian fish" can definitely be considered a cladeI agree that "sarcopterygian fish" is a clade, actually.


And I'm surprised that you use both clades and Linnaean ranks, to be honest....These things happen when dragging non-cladistic systems like "fish" or the like into things. We use what works and gets the message across, don't we? The Linnean stuff still has some meaning to impart, even if it's not always the best way. Not by first choice, of course, I'd prefer a straight cladistic approach without ambiguity.

[Darwin's Finch]

Nope, I mean paraphyletic, as I understand it viz. a group that contains all "fish" up to their last common ancestor also contains things that are not "fish" viz. all the tetrapods. But that last common ancestor was probably a fish, too (i.e. a swimmy finned thing).
For it to be polyphyletic, it'd have to exclude the ancestor and be a wholly artificial grouping (like grouping birds, pterosaurs and bats together as "flyers" when their last common ancestor was not a "flyer").

In general, a paraphyletic grouping can be expressed as "clade A - clade B". E.g., "non-avian dinosaurs", which is composed of all dinosaurs except for birds.

For fish, it depends on where the clade for fish "begins". You could say, for example, that "fish = Craniata - Tetrapoda", but there are a lot of pre-Craniata chordates that look pretty fishy. And you also have hagfish in there, looking all snakey and non-fishy. If you move it back to Chordata, then you also have the decidely-un-fishlike tunicates mucking up your definition (that is, fish = Chordata - Urichordata & - Tetrapoda).

If we go by Wikipedia's defintion, "a fish is any aquatic vertebrate animal that is covered with scales, and equipped with two sets of paired fins and several unpaired fins." then we are still leaving out a bunch of critters (basically, anything before placoderms [since placoderms were the first major group to have two sets of paired fins], despite their decidedly fish-like appearance).

So, to my mind, since "fish" cannot easily be expressed as "clade A - clade B", they are more poly- than paraphyletic. That may or may not be strictly true, but that's my take on it. It can potentially be made paraphyletic by stating "fish" = Gnathostomata - Tetrapoda, but that remains unsatisfying to me because of all the fishy stuff between Chordata and Gnathostomata. I'm not even sure it's possible to define fish using a crown-based definition ("the common ancestor of Taxon A and Taxon B, plus all its descendants"), since no matter what you pick, you're probably not going back far enough unless you make it so general that that it becomes synonymous with Vertebrata.

The traditional definition of fish, it seems to me, is more gradistic than cladistic.

[MrDibble]

Fish are Craniata - Tetrapoda, at least to me. And hagfish are "fish" just as much as lampreys are.

And I think it's a bit disingeneous for you to take Wiki's first, simplest definition when the next section goes on to say:
The term "fish" most precisely describes any non-tetrapod craniate (i.e. an animal with a skull and in most cases a backbone) that has gills throughout life and whose limbs, if any, are in the shape of fins. (http://en.wikipedia.org/wiki/Fish#Diversity_of_fish)Exactly what you say you don't agree with. Note also where it says:Fish are a paraphyletic group: that is, any clade containing all fish also contains the tetrapods, which are not fish. My emphases.
Just do a google search - there are no relevant results for "fish are a polyphyletic group", whereas "fish are a paraphyletic group" returns 33 000 hits. If even 1% of those have relevance, that's a lot more than think fish are polyphyletic.

[MrDibble]

The traditional definition of fish, it seems to me, is more gradistic than cladistic.I agree with this.

[Darwin's Finch]

Disingenuous? Wha? I was just using that definition as another possibility. Geez, I thought this was just a friendly disagreement....

So long as you consider conodonts "fish" and critters like Pikaia as non-fish, then I agree that fish is paraphyletic.

[Darwin's Finch]

Fish are Craniata - Tetrapoda, at least to me. And hagfish are "fish" just as much as lampreys are.

And I think it's a bit disingeneous for you to take Wiki's first, simplest definition when the next section goes on to say:[/URL]

I would also like to point out that Wikipedia [url="http://en.wikipedia.org/wiki/Diversity_of_fish']disagrees with itself (http://en.wikipedia.org/wiki/Fish#Diversity_of_fish) on this definition:

The term "fish" describes any non-tetrapod chordate, (i.e., an animal with a backbone), that has gills throughout life and has limbs, if any, in the shape of fins.

So on the one hand, they are Craniates - Tetrapods, on the other they are Chordates - Tetrapods. And it uses the same source as the cite for both!

They go on to discuss whether the so-called "jawless fishes" are actually fish or not, despite the fact that many are basal gnathostomes, and those are quite definitely craniates. And that hagfish are "the only fish which aren't vertebrates", when they just said that "fish" goes all the way back to Chordata!

Not that I'm using this to discount what you said, just that Wikipedia itself seems a bit confused on the matter. It's entirely possible that the Chordate reference is in error.

[Irishman]

Since this thread is about what you know about evolution from just your own head, let me just say that classification is one of those things with which I am insuffficiently informed.

I'll try reading the links.

Regarding terminology, just remember that sometimes scientists take existing terms and then mangle them to suit their own needs, such that the modern scientific use does not necessarily bear any relation to the common use. An example might be "planet" or "star", for instance, and "dinosaur" also fits that category.

Was watching a science program on History Channel last night that mentioned the time when the "dinosaurs ruled the land and the sky". It's my understanding that most of the flying things at that time were not what is currently classified as dinosaurs, even though they were big, scaly, scary things.

[Darwin's Finch]

Regarding terminology, just remember that sometimes scientists take existing terms and then mangle them to suit their own needs, such that the modern scientific use does not necessarily bear any relation to the common use. An example might be "planet" or "star", for instance, and "dinosaur" also fits that category.

It's not so much an attempt to mangle the terms, but to standardize them. if everyone has their own personal definition of what a "monkey" or "ape" or "dinosaur" is, then it becomes difficult to discuss any of these groups without lengthy explanations as to which definition, exactly, you are using. And if folks don't agree on definitions, then discussion effectively goes nowhere.

For the most part, scientists agree on their definitions. The problem, really, is that the public awareness of changes in terminology lags behind the "official" acceptance. So, while paleontologists can agree on what a dinosaur is (or is not), popular culture still lumps pterosaurs, Dimetrodon (which wasn't even a Mesozoic animal!), plesiosaurs and mosasaurs as "dinosaurs". The trick is getting all of this out to the general public (who, I think, seems to be coming around to the whole "birds are dinosaurs" thing finally, albeit slowly).

Was watching a science program on History Channel last night that mentioned the time when the "dinosaurs ruled the land and the sky". It's my understanding that most of the flying things at that time were not what is currently classified as dinosaurs, even though they were big, scaly, scary things.

While there were certainly flying birds around during the Cretaceous, the Mesozoic fliers most folks are familiar with were pterosaurs. Which, while not currently considered dinosaurs, were certainly closely related to them.

[MrDibble]

Disingenuous? Wha? I was just using that definition as another possibility. Geez, I thought this was just a friendly disagreement....I wasn't trying to be unfriendly, honest. Sorry about that. I apologise completely, both for the word and the tone. I think I was just a little miffed that you quoted a Wiki article that says right there that fish are para.


So long as you consider conodonts "fish" and critters like Pikaia as non-fish, then I agree that fish is paraphyletic.
Well, I do. Conodonts are definitely in, since the latest discoveries (South African, too! I'm quite chuffed) point to a lamprey/hagfish-like physiology, and Pikaia is definitely out, like lancets.

I agree that Wiki is confusing - perhaps because Craniata is such a new grouping? I've tried looking up the reference, but my nearest library doesn't have the 2006 edition yet, damn it. Call themselves a University!

[Dick Dastardly]

Proof of Martians 'to come this year'


Final proof that Mars (http://www.scientificamerican.com/topic.cfm?id=mars) has bred life will be confirmed this year, leading NASA experts believe. The historic discovery will come not on Mars itself but from chunks of the red planet here on Earth.

David McKay, chief of astrobiology at NASA's Johnson Space Centre in Houston, says powerful new microscopes and other instruments will establish whether features in martian meteorites are alien fossils.

He says evidence for life in the space rocks could have been claimed by the UK if British scientists had used readily-available electron microscopes. Instead, images of colonies of martian bacteria were collected by American scientists.

The NASA team is already convinced that colonies of micro-organisms are visible inside three martian rocks (http://news.skymania.com/2009/11/ancient-martians-were-carried-to-earth.html) that landed on Earth. If so, this would have profound implications for our understanding of life in the universe.


http://www.scientificamerican.com/article.cfm?id=proof-of-martians-to-come-this-year-2010-01


Assuming they discover biological stuuf in these rocks, how will this affect the views of the people who don't believe in evolution? Will this just be another test that god made to test the faith of true believers?

[Taber]

[B]

Assuming they discover biological stuuf in these rocks, how will this affect the views of the people who don't believe in evolution?

It is a miracle! God made life on other planets 6,000 years ago too!