The Merits of Evoltion: A Scientific Debate

Great Debates
1

LETS GET READY TO RUUUMMMBLE!!!

First off, Lets keep this a clean fight, nothing below the belt yada yada yada. In other words, lets keep this as unreligious and scientific as possible. This goes for both fundies AND atheists (IMHO alot of ‘atheists’ are anti-religious, while a true atheist would be unreligious).

I would like to debate the merits of Evolution as a scientific theory. Lets assume for now that it is just a theory and not a scientific ‘fact’/law.

I do not want to debate if evolution is correct or incorrect for that has been done many times here. The goal is to use as much empirical and objective ‘proof’ as possible. I definitely do not want this to turn into a fundie vs atheist, Creation vs evolution war.

For now lets assume there is another theory of origins just as good and scientifically accurate as evolution. The other theory is moot, her Holy Horniness (may her hooves never be shod!) may have shat and from thence came Life, The Universe, and Everything; it does not matter.

Once again, please keep an open mind.

Before we start, lets define Evolution (we can expand this as we go along).

According to my HS Biology teacher (this was a long time ago so I may have it wrong):
Evolution is the slow change over time due to natural selection and other factors that results in speciation(the ‘creation’ of new species different from the parent species)
ROUND 1!
For a start let’s ‘test’ this theory. Scientific theories are tested mainly by 3 factors:

  1. Process. Does the theory adequately explain the observations? According to this theory should there be other observable phenomenon and there isn’t? And, most importantly, Does this theory work well with and follow other well established scientific laws?

  2. Parsimony. Does this theory require many starting assumptions? Does this theory have a good assumption/explanation ratio? (i.e. With one assumption does it explain many observations?) Must we add assumptions to explain more recent observations or does the theory ‘stand on its own’ well? Does this theory rely on other theories(and therefore on the other theories assumptions as well)?

  3. Prediction. Can this theory be used to make predictions that should be tested true? Predictions are the most important test of any scientific theory.

Will someone please dig up and list the assumptions of evolution (both direct and implied)? If you have any knowledge of epistemology, keep that in mind when you list/hunt for them (hint: This is a call for the very epistemologically minded Spiritus Sancti if you are out there…)

Ok, that’s it for now.
‘LETS GET IT ON!’
-Fox
“Minds are like parachutes: They only function when open.” (this applies to fundies AND atheists alike)

“I can’t explain myself,” said Alice, “because I’m not myself, you see.” -Alice’s Adventure Under Ground

2

“Only a theory” is a term long bandied about by anti-evolutionists. It’s silly. We would hardly consider gravity to be “only a theory,” would we?

The answers to most of your questions can be found at http://www.talkorigins.com

3

I agree with andros. Since you started off calling it “only a theory”, I think you need to take a step back and realize what that means. Theories are the ultimate goal of science, not Laws. It’s a fact that evolution occurs. The Theory of Evolution explains how.

I also highly recommend reading through this website
http://www.talkorigins.org/

You’ll also find a better definition of evolution there.

Having said that, maybe we can still debate your “3 factors”.

4

Wow, the first post is already a Fundie vs Atheist one (more anti vs pro evolution). Like I said before lets tackle this scientifically, and please ignore the pro vs anti evolution aspects of this debate.

deep breath

By ‘gravity’ I assume you mean the ‘Law’ of Gravity and not the phenonomen we observe by sticking to the ground. Furthermore let me point out I refer to the Theory of Evolution not the phenomenon we observe in biology of diversified speicies with similar characterists that seems to suggest they have a common ancester.

another deep breath

Actually, the ‘Law’ of Gravity IS just a theory, altough a highly ‘proven’ and ‘accepted’ one. Furthermore, it breaks down/doesn’t apply to extreem situations such as inside a black hole and ‘before’/during/right-after the Big Bang. As you can see from tenent #1 of the theory test crterion, this fails that part of the test. This is why scientists have been searching for a ‘Grand Unification Theory’ for decades, and why Quantum/Partical Physics (as well as Superstring Theory) attempts to explain why this happens. As you may know, Evolution is far less complete than the Law of Gravity.

another deep breath, starting to feel light-headed

What I was taught was that a Scientific Law is a highly proven and accepted Scientific Theory. A Scientific Theory is a Highly proven and Accepted Scientific Hypothesis. A Scientific Hypothesis is a testable explanation that explains a set of observations. So in realty, Evolution is just a theory. (yes, yes I know this fact is misused by anti-evolutionists, but its the truth)

According to most pro-evolution literature i’ve read, they do not call Evolution a Law, or Theory or anything much Evolution. They seem to equate it to a ‘force’ such as gravity. Evolution is not force, it is an explanation for observed phenomenon that is highly accepted. As you can see, that is definition of a Theory (or with a big stretch, a Law).

*another deep breath *

Dictionary.com:
The THEORY that groups of organisms change with passage of time, mainly as a result of natural selection, so that descendants differ morphologically and physiologically from their ancestors.

IMHO: The ‘Evolution is not a theory’ argument of Evolos is just as bad and has as much merit as the Anti-Evolvos ‘Evolution is just a theory’. But like I said, lets try to keep this scientific. BTW, both arguments are irrelevent to this debate, like I said in the OP ‘lets assume Evolution is just a theory’. If you need help with that, pretend that we rolled the clock back a few years when evolution was ‘just a theory’.

deep, wheezing breath

Sorry to the rest of you (if there is anyone out there) for that rant, I just hate it when someone posts to a thread saying the discussion is irrelevant. If someone doesn’t want to discuss something, dont! Its that easy.

-Fox

falls over unconscious from hyperventilation
“Minds are like parachutes: They only function when open.” (this applies to fundies AND atheists alike)

“I can’t explain myself,” said Alice, “because I’m not myself, you see.” -Alice’s Adventure Under Ground

5

Just one more thing about theories/laws then I’ll shut up about it & join any ensuing debate on your actual questions.

It looks like what you were taught is not quite right. From the National Academy of Science…

By the way, here’s a discussion on the definition of evolution…
http://www.talkorigins.org/faqs/evolution-definition.html

also by the way, welcome to the SDMB!

6

Thank you for the clarification and warm welcome, phobos.

It seems to me that you are saying my definition of Law = their definition of fact. That I can accept. I thought they meant more along the lines of “an absolute truth” ie I drop an apple, it falls.

We can still debate along the lines of the OP, although we may need to revise it a bit. I think this is because ‘Fact’ = highly proven Theory.

Still, the fact of evolution is still just an explanation based on observations. Ill expand on this point later, but I need to get to my other job soon.

Interesting definition of evolution. So this includes everything from natural selection to speciation, correct?

I looked through the Introduction to Evolutionary Biology FAQ and it seemed to have very little substantial evidence and very little logic other than circular. Also, it seemed to outright accept evolution as the ultimate truth and take it for granted.

I need to beef up on evolution for this discussion. (back when I was in school, they must have taught us a VERY flawed version of evolution. darn public school system…)

Oh and BTW, phobos, thank you for taking the time to give an adult, educated, response in support of your point instead of just-your-point-and-must-be-accepted, like some posters do. (this is not sarcasm and is a genuine complement)

-Fox

“Minds are like parachutes: They only function when open.” (this applies to fundies AND atheists alike)

“I can’t explain myself,” said Alice, “because I’m not myself, you see.” -Alice’s Adventure Under Ground

7

Why would a true atheist be unreligious as opposed to anti-religious? For someone trying to have a completely scientific discussion, you’re off to a bad start.

And the bad start just gets worse. In science, a theory is pretty much the same as a fact/law. A theory does not “become” a law when more evidence is found. A theory is already “as good as it gets.” There is no potential discovery which would cause scientists to say "Aha! There’s the final piece of the puzzle–we can no upgrade evolution from “theory” to “law.” It just doesn’t work that way.

I’m a little confused here. What else is there to debate beside the (in)correctness of evolutionary theory?

Huh?

Speciation is evolution, but not all evolution is speciation. The most open-ended definition of Darwinian evolution is “a change in allele frequency over time.” This also rules out such nonsense as Lamarckianism.

Looks like somebody’s already done all of this for you. Check out: http://pages.hotbot.com/gene/zthibault/images/MacroProofs.pdf

Numerous predictions of evolutionary theory, along with the evidence that supports it. Also listed are all the potential falsifications. Debate over.

8

(1) Yep. Natural selection, sexual selection, genetic drift, mutation, recombination, & gene flow. It’s meant to be the most basic of definitions. If I’m understanding it correctly (I’m not a biologist), it’s the ebb and flow of genes. You won’t get speciation from one generation to the next, but each generation makes its small contribution to what genes survive. It doesn’t mean that a child “evolved” blue eyes if the parents have green eyes, but if you were able to quantify the genetic traits of the entire population, you may see the average slightly change over many generations. Over thousands/millions of years, this adds up to speciation.

(2) I’ll have to re-read the “Intro” article to see what you’re referring to, but my first thought is that they are presenting the entire website (and newsgroup) as a body of evidence rather than summarizing it in one place. The authors of the website are definitely convinced supporters of the Theory, no doubt about that. They’ll debate the details, but the Theory is accepted.
I’ll have to think some more about your 3 questions in the OP.

9

Foxfyre, if I may take the liberty of imagining your purpose here…you probably feel that since both evolutionists and non-evolutionists feel strongly about their beliefs, that there should be some middle ground where we can take the good from both theories and discard the bad from both theories and reach a synthesis that is more complete than either would be separately.

Well, sometimes that just doesn’t work. Sometimes, one theory is completely wrong, and the other has hit the facts on the nose. And that is the case with evolution.

To help with some definitions. Natural selection is a theory…an explanation of the facts of evolution. Sometimes people equate natural selection and evolution, because natural selection is the only commonly accepted theory of evolution, but others are logically possible, although most seem to be empirically disproved.

For instance, we can imagine a Lamarckian theory to explain the facts of evolution. However, this theory fails because there is no way for the somatic information to be transmitted to the germ cells. Or we could imagine some vital force that directs evolution. But this theory fails because we have never discovered anything other than ordinary physics and chemistry operating in living systems. So there seems to be no reason to invoke vital forces, in fact there are good reasons to reject them.

So, how do we explain the facts that certain species seem similar, the patterns of their variation, and how fossils are distributed? Well, one explanation is that organisms typically have more offspring than would be neccesary to replace the current generation. And that those offspring will vary, and that that variation is often heritable, what we now call genetic variation. And, that since only a certain percentage of the offspring survive and reproduce the next generation, it therefore follows that different generations are not going to be genetically identical…that some variants are going to have more than their share of representation in the next generation, and some less.

Currently, the theory of natural selection holds that this is the only mechanism needed to explain the facts of evolution.

There may be other mechanisms, but no one has demonstrated that they actually exist, where we have conclusively demonstrated that the theory of natural selection does, the most obvious example is the evolution of drug-resistant bacteria through natural selection.

Does this help?

10

Natural selection working on genetic variations in populations, supplemented by “drift” and other non-selective changes in allele frequencies, seems to be an adequate explanation for the odserved variety of existing life and the remains of extinct forms.

I am not quite sure what the OP is trying to ask.

11

Preview, dammit.

I apologize to all for the obvious failure of my language skills in my last post…

12

foxfyre wrote:

Are you talking about the FAQ at http://www.talkorigins.org/faqs/faq-intro-to-biology.html?

It has a whole section titled "Evidence for Common Descent and Macroevolution, at http://www.talkorigins.org/faqs/faq-intro-to-biology.html#ecd. I’d say introns and pseudogenes count as pretty darn substantial evidence.

13

Yup…the fallacy of the happy middle or something like that. To paraphrase Jim Hightower, sometimes the only thing in the middle is the double yellow line and dead armidillos.

Not that there isn’t room to debate in the evolutionary community. Hell, I am sure there are huge debates going on. For example, I know that Stephen Jay Gould made a name for himself with his theory of punctuated equilibrium, whereby the changes brought on by evolution are not “gradual” (at least on the long time scales biologists are talking about) but tend to occur in rapid fits and starts, e.g. when small subpopulations get separated from the main population then changes can occur quite rapidly in that subpopulation. (Someone may have to correct me on the details here…Biology ain’t my field!)

Gould also argues that the popular conception of evolution as a process of continuous improvement and ever-more complexity is a misconception. I.e., he believes “noise” in the form of randomness may play a much greater role in many cases than the pressures of natural selection. And, he notes that although the distribution of organism complexity has expanded out on the high-complexity side, this is more just a matter of the fact that there is nowhere to go but up from a one-celled organism and that one-celled organisms are still kings of the earth in terms of biomass.

Anyway, all of this is to say that there are plenty of reasonable subjects to debate within evolutionary theory (although I doubt that either you or I are really competent enough in the field to debate them ourselves). But to suggest that evolution might be fundamentally wrong is more like proposing that perhaps “there is no gravity and the earth sucks” than it is that the theory is incomplete in the sense that there are certain limits in which the forces of nature are described by a grand unified theory, superstrings, etc.

I like the “minds are like parachutes…” quote, but another good one is to keep in mind is that “you should always have an open mind but not so open that your brains fall out”!

14

1.a. Yes, evolution adequately explains the observations: The fossil record; the whole pattern of “branching tree” taxonomic categories (lions and leopards are very similar to each other, and less so to cats; the felids in turn belong to a larger group of carnivores, including dog-like animals and bears and other groups, with certain basic similarities; the carnivores in turn are mammals, which, though very diverse, share certain basic traits with each other which are not found in any non-mammals; mammals are vertebrates, etc.); the deep anatomical similarities between the legs of an antelope, the wings of a bird, and the flippers of a whale; the existence of air-breathing marine animals; Darwin’s finches; the way sickle-cell anemia works; the current rise of antiobiotic-resistant bacteria; or the fact that when a male lions runs off another male lion, takes over his pride, and kills the cubs of a female in the pride, she goes into heat. We have a poster around here named Ben who will likely be by soon to discuss “protein homology”.

1.b. I don’t think so. Do you have any examples?

1.c. Yes, certainly.

  1. I’m not sure you’re trying to get at here. Are you saying that a good theory shouldn’t be in accordance with observations or well-established theories from other branches of science? You seem to be contradicting point 1.©. above. For example, biologists rely on the findings of geologists that this planet is billions of years old. It would be a problem if biologists didn’t rely on other theories; if for example, biologists’ theories indicated that the Earth ought to be 17 minutes old or something like that. In fact, around the turn of the 20th Century there was a serious problem in science; the astronomers at that time had theories about how the Sun worked which meant it (and therefore the Earth) could not possibly be old enough for the biologists to have the time they needed to account for modern life by evolutionary processes. It turned out the astronmers were wrong; once they figured out the details of thermonuclear reactions, they came up with an age of the Sun which nicely fitted in with the observations of geologists and biologists.

Again, Ben will be able to talk about protein homology in much greater detail. In general, evolutionary biology has nicely predicted the findings of molecular biology (analysis of DNA or protein sequences). In other words, the proteins of lions and leopards are more similar to each other than they are to the proteins of wolves, and progressively less similar to the proteins of kangaroos or frogs or oak trees. Darwin also realized he needed something like the modern idea of the “gene” before anyone actually found any such thing. And there are those antibiotic-resistant bacteria.

15

Also, people say “evolution is a fact” (as well as a theory) because it is a fact; in other words, it is just as much a fact that current living things share common ancestries and that over time organisms are transformed into new lifeforms as it is that matter is made of molecules and atoms and subatomic particles, or that the Sun is a star like the other stars you see in the sky but much closer.

16

MEBuckner, let me explain Parsimony a little better.

(I am not saying this theory is false, I’m merely using it as an example)
"Heres an example (from a website, I forgot which):
For example, another attempt to explain dinosaur extinction claims that a large asteroid or comet struck the earth. The asteroid, containing the rare element iridium, kicked up a worldwide dust cloud that blocked out sunlight for several years, reduced photosynthesis on the earth, and choked off the dinosaurs’ food chain. Support for this theory comes from a thin but widely spread layer of clay in Europe, New Zealand, and elsewhere that contains iridium. This iridium-rich layer is found near many dinosaur fossils. An asteroid or comet striking the earth might explain the worldwide extinction of dinosaurs and a widely spread iridium layer near many dinosaur fossils. In other words, one starting condition (an impact of a large asteroid or comet) explains two important observations: dinosaur extinctions and the iridium layer. This is good.

But there are some hidden assumptions. While iridium is frequently found in some meteorites, it has obviously not been found in asteroids or comets, since they have never been captured. Therefore, we must assume that asteroids or comets have large amounts of iridium. Other iridium-rich layers have recently been found above and below the original layer. Did other asteroids strike the earth before the one that destroyed the dinosaurs? Why did the dinosaurs survive those earlier impacts? Why were no other extinctions associated with these other iridium layers? Each question can be answered by making new assumptions. However, by Criterion 2, this reduces our confidence in the theory."

Also in that example is an example for 1b. According to this theory, the other iridium layers should have mass extinctions as well, but they dont.

I will be studying up on Evolution today, most of what I know about it is from biology class and fundie propaganda. The way they taught Evolution back in public HS made it seem very unlikely to be true. Ill hopefully post again later today.

:frowning: my first OP pretty much crashed and burnt

-Fox
“Minds are like parachutes: They only function when open.” (this applies to fundies AND atheists alike)

“I can’t explain myself,” said Alice, “because I’m not myself, you see.” -Alice’s Adventure Under Ground

17

As far as I know, there are no hidden unwarranted assumptions underlying modern evolutionary theory, and as far as I know there are no unfulfilled predictions of modern evolutionary theory. It’s easy to present evidence for something, but harder to prove the negative that there are no evidences against it. It might make the discussion go better if you were to present some possible evidences against evolution, and we can all discuss whether or not they really qualify as such.

18

Ok, while Im studying up on Macroevolution, lets get back to the OP however flawed it may be. What I want to debate is macroevolution, because it is not directly observable. (and it is what I was taught WAS evolution)

Lets start with the assumptions. Lets first list all the assumptions and debate things later. For now lets ignore if they are supported or unsupported by observations. It would be very helpfull if you have a decent knowlege of epistemology (study of knowlege) for this.

  1. Somewhere, somehow, an organism came into being that stored a blueprint of how it constructed itself and passed this blueprint to its children. (To the best of my knowledge, evolution only deals with the diversification of life, not the origin of life. Correct me if im wrong.)

  2. Microevolution is true. (we can ignore all the assumptions of microevolution because it has been observed)

  3. Microevolution can lead to speciation.

  4. The Earth, Universe, etc is VERY, VERY old.

  5. Macroevolution is the only way present day life is the way it is.

Im sure there are more and ill post them if I think of them

-Fox
“Minds are like parachutes: They only function when open.” (But shouldnt be so open your brain falls out!)
-thanks jshore

“I can’t explain myself,” said Alice, “because I’m not myself, you see.” -Alice’s Adventure Under Ground

19

This is off topic, but I think there are points in your asteroid example that should be clarified.

The iridium-rich layer is found purt’ near anywhere you look where the geographic strata are preserved from 65 mya. Its geographic or stratigraphic location relative to abundant dinosaur fossils is utterly irrelevant–dinosaurs die and are fossilized even when there isn’t a catastrophe, so you don’t expect to find more fossils associated with the catastrophe (unless, I guess, the catastrophe does something to encourage fossil preservation.) The relevant evidence is that deeper than the iridium layer, you find dinosaur fossils. Above the iridium layer, you find no dinosaur fossils.

An asteroid that hits the Earth is a meteorite. Some classes of meteorites have spectroscopic characteristics in common with asteroids, so one can confidently conclude that they represent material from the asteroid belt. Further, the reason you don’t find much iridium at the Earth’s surface is that the Earth is a differentiated body; when it melted, the heavy metals (like iridium) tended to sink toward the core. One expects to find more iridium in meteorites that come from undifferentiated bodies (such as comets or small asteroids), or from the cores of differentiated bodies that have been broken apart. The chain of reasoning is stronger than you make it seem.

**

This is very interesting! Can you provide a cite? I’d like to read more.

20

The origins of life is certainly one of the murkier areas of biology, and I don’t think anyone would say otherwise. Once you let the biologists have a “simple” organism–a bacterium, say–they don’t seem to have any real problems going from there to whales and petunias and Britney Spears and so forth–but of course a bacterium is a pretty big step up from lifeless primordial goop, and no one things it happened in one fell swoop. We have evidence for bacteria from as far back as 3.5 billion years ago, so whatever happened happend a looong time ago, and the evidence is going to be difficult to puzzle out after a few eons of radical atmospheric changes and a whole biosphere doing its thing. Space exploration may conceivably hold the best hope for clues on this one.

Beware that this distinction between “micro” and “macro”-evolution may not hold up all that well.

The Observed Instances of Speciation and Some More Observed Speciation Events pages on the Talk.Origins site discusses instances where speciation has actually been observed to take place.

This one is so well supported–by geology, astronomy and cosmology, nuclear physics, etc.–that it can be moved over into the “fact” column.

Hmmm…well, macroevolution does account for the way present day life is, and alternative “theories” don’t, in any meaningful way. (Saying “Whales are air-breathing marine mammals because God made them that way” doesn’t count as an “explanation”.)