Inviting ALL evolutionists to show proof that mammals evolve

Great Debates
81

andros,

You wrote:

You are privy to information about Phaedrus that I am not. I sympathize with your annoyance. So far, in this thread, he has demonstrated himself to be somewhat of a flake, but I haven’t seen anything that strikes me as downright obtuse. I haven’t seen anyone answer his original challenge to demonstrate evidence that mammals evolve.

I’m not sure I even know what the entire body of the theory called “natural selection” is. What I was referring to is the portion of the theory which says small random variations are favored and propagated if they allow an organism to survive longer in order to reproduce. What I’m suggesting is that the majority of people who believe in evolution also believe that this is the principle driving mechanism. It may be… but I tend to have a more open mind about it. There are a lot of evolutionary steps that this mechanism can adequately explain, but there are other evolutionary steps that may not fit this kind of model so readily.

How do we know that organisms that had a clear competitive advantage didn’t die out while inferior organisms thrived due to sheer luck? How do we know the variations are random? How do we know that just because some organisms evolve, that all of them do? How do we know that organisms evolve indefinitely? Perhaps they evolve to a point and then begin to ‘devolve’… There are things in the evolutionary tree that seem to defy explanation, with respect to natural selection.

[slight side track]
In the dark ages of the theory of gravity, before Newton, most theories of gravity were supernatural or devine. People knew basically what to expect and were able to take advantage of gravity to do many useful things, but the theories were flawed, nevertheless. Then along came Newton and he presented a new, better theory of gravity. His theory was that all mass exerts a force which is inversely proportional to the distance from the center of mass. The theory lasted many years because it seemed to explain the way things behaved in the real world. Then Einstein came along and challenged this notion. Einstein and others pointed out a few examples that didn’t match the expected results from the flawed Newtonian theory and so the theory ‘evolved’. Einstein postulated that gravity operates the way it does because space-time curves around things with mass. Einstein’s theory was considered a better theory because it explained observable phenomena more precisely and more predictably. I wouldn’t be surprised if, within the next 50 to 100 years a new theory of gravity emerges that replaces Einstein’s theory.
[/sidetrack]

My point is that there is often a distinction between what we think we know (those things that seem plausible and that there is sufficient physical evidence to support a given theory) and what we actually know. With our understanding of evolution, we are still very, very immature (possibly still in the dark ages of evolution theory).

Getting back to my original point (or was it a secondary one?): Many scientist seem to be afraid to open their minds to other alternatives. Partially because they just can’t conceive of any other alternative so they steadfastly defend the only one they can think of. Partially because they fear that if they open the door to any alternative thinking that the creationists will force their way in and topple the delicate towers of scientific knowledge.

… just my opinion.

82

Could somebody sum up? I’m finding reading all this a bit tiring right now. I believe that people have asked Phaedrus [paraphrase]“If you believe non-mammals speciate, what makes mammals different so that they don’t?”[/paraphrase]. Did they? Did he answer? If no to either, I pose the question again.

And if, on the offchance that Phaedrus does not believe mammals don’t speciate or if he discards that belief, then what’s to stop a species from speciating, then the result doing it again, then again and again, and so evolving? And since other classes (mammalia is a class I believe) can do this, then why not mammals?

83

Surgoshan,

The signal-to-noise ratio has been pretty low… Here’s my assessment (somebody chime in if you disagree):

Phaedrus stated that he does not believe that mammals speciate. His definition of speciation was stated in an earlier post:

Phaedrus’s challenge was to provide evidence that mammals do speciate. He acknowledges that mammals can and do exercise some level of evolutionary flexibility.

I don’t believe that there has been any evidence presented thus far that meet with Phaedrus’s criteria. There was the mention of some fossil evidence, most notably the horse. Phaedrus does not necessarily accept fossil record as sufficient evidence. I tend to agree. As an example, suppose a few million years from now archeologists dig up the fossil remains of a dachshund and a doberman. From a physiological standpoint, there is a striking difference. Yet we know that these are two variants of the same species and, notwithstanding the logistical challenges, they can mate and pass on their genetic material. We deduce from the fossil record that Equus evolved from Hyracotherium, but do we know that they were truely different species? Common sense says yes, but nature doesn’t always follows the rules of common sense, as we see it. Assuming Hyracotherium and Equus are different species, can we prove that Equus is a decendant of Hyracotherium? I suspect that DNA evidence for the latter is probably very strong, but I don’t know if we can tell if two animals are different species (by Phaedrus’s definition) from DNA. This seems to be the best tact for demonstrating that mammals do indeed speciate. So far either no one’s taking Phaedrus serious enough or we simply don’t have the core knowledge available to this group to shed any light in this direction.

Meanwhile, Phaedrus bailed, which usually spells doom for one sided threads like these…

84

Joey, I haven’t “bailed” I am typing something up offline and will post it in due time. Been busy “practicing” law and quick posting elsewhere.

85

Sorry Phaedrus, I must have misunderstood. I thought you were completely gone for some indefinite period of time. I wasn’t judging, BTW - I have a real job too…

I also have a lawyer who I wish would spend more time on my case than he does playing golf or whatever…

86

In Answer to Phaedrus’s Challenge

First and foremost, this is a long post but stick with it. I think that my points are valid and knowing the thought process that went into them sometimes helps.

Second, my training is in how small things influence big things (genetics, biochemistry, physical chemistry, microorganisms and the like) so I have a slightly different view than evolutionary biologists. Keeping that in mind should also help everyone understand how I got here.

An initial thought (there will be several). It takes proof to get rid of a theory, not establish one. If there were proof that a theory is correct then it would no longer be a theory but a law. Nobody calls it the law of evolution.

Any serious discussion must begin with the definition of the terms that you are after discussing: I have read the ones provided here and find that they are lacking in a level of preciseness that should be required (seriously not an attempt at slamming or humor: We at the FBI have no sense of humor that we are aware of J.) Here is a precise definition of evolution.

Evolution: The change in allelic frequency over the course of a generation or several generations for
a population of organisms.

This view has changed since Darwin (who was really off on most of his thoughts) to correct for our current understanding of how organisms grow and change. Here are a couple excerpts from texts that I have read on the subject.

“In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages, and political systems all evolve. Biological evolution … is change in the properties of populations of organisms that transcend the lifetime of a single individual. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population to the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions.”

     - Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986

“In fact, evolution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next.”

     - Helena Curtis and N. Sue Barnes, Biology, 5th ed. 1989 Worth Publishers, p.974

Most people seem to associate the word “evolution” mainly with common descent, the theory that all life arose from one common ancestor. The common descent theory is only one part of the theory of evolution and kind of a side issue at that. All life varies the frequency of alleles expressed from generation to generation, period. Common descent is another critter altogether.

(your definition)____________________________________________________________
…that all life has evolved from the most humble of beginnings. I mean that mammals can change into other mammals and those fruit flies can change into birds or that monkeys (read pongoids) can change into men. Evolution is the idea that life can develop from a single cell into the complexity and diversity of all the living forms we see around us.

Common descent is something that I don’t think we will ever be able to demonstrate, simply because it is the next closest thing to impossible to say what happened 4.5 billion (or 20,000 or 6,000 depending on who you listen too) years ago.

I assume that the bulk of your issues with evolution stem from the common descent theory and not from actual evolution.

I believe that further evidences concerning evolution cannot be found because the mechanism does not evidence itself in any way that is observable in nature or testable in a lab.

Three things on this statement:

  1. BAD ATTITUDE FOR A SCIENTIST TO HAVE!!! Or any rational adult besides. To assume that we have all of the knowledge we will ever have is short sighted to say the least.
  2. The mechanism of an event is not required to show that an event actually takes place. Consider the melting of an ice cube. Everyone knows that once the temperature rises above the melting point of water, the ice will not stay in a solid phase. Unless you have done your Physical Chemistry homework however, you couldn’t explain the mechanism to me. Still even before we knew the mechanism - everyone knew that ice melted when it got hot.
  3. The fact that you discount the possibility of finding further evidence begs the question of whether or not you will accept the evidence that I have provided on the subject or any evidence that I might introduce. I would then ask you - why waste your time on this board? I haven’t seen any alternative theories presented here, which leads me to wonder about the theory you prefer. The way science works is you stick to the theory you have that best describes the event that you are studying. When a better one comes around, dismiss the old one and focus on the new one. You cannot expect people to replace a theory that goes a long way towards explaining things with nothing.

As far as speciation here is what I have to say on the matter.

First, I have no problem with your definition of this. It is pretty standard - the evolution of one breeding stock to another.

Second, I am curious as to why you dismiss all fossil records and fossil studies out of hand. You must have some reason to invalidate an entire field of science - and hurt a lot of paleontologist’s feelings besides.

Third, there is evidence that two different species can breed and produce viable offspring. The wolf and the dog, the house cat and the serval (wild cat). They are different species, and yet they produce viable children. Just a thought to ponder.

Also, what makes you think that mammals are on the top of this evolutionary scale? When was the last time you saw a mold looking for an antibiotic for you or me? I don’t know about you but I would have a hard time living through a hard vacuum or cosmic radiation, yet the mold doesn’t have a problem with it. Just another thought.

Next, consider the very well documented cases of the Founder’s Effect, which applies to all organisms, single cell up to mammals.

For those who aren’t familiar with it, the founder’s effect is similar to genetic drift except that it describes a single sampling of a very small population from a large one due usually to a natural disaster (earthquake that separates some portion of a population from the mainstream group) or by way of relocation of a small number of the population to an isolated location. The real mechanism of the founder effect is found not principally in the sampling errors involved in drift but in inbreeding of the now isolated population. The small population experiences dramatic inbreeding which leads to the greater expression of otherwise rare combinations of genes that in a larger population would never be seen (usually due to the trait being recessive). Some of these combinations may be advantageous in the new environment and will increase fitness of the population. This is evolution and has often resulted in speciation (plants mostly since they are easier to isolate but their is speculation that the radical seperation of species seen in Australia from what scientists consider their parent species in the evolutionary tree is a result of this as well. Since you don’t accept fossil records as evidence and if you need “proof” past this point you don’t accept genetic evidence either, their really isn’t anything that I can give you that you will accept on this point so I will leave it here).

OK, now I’d like to digress (again) for a second and correct what appears to be a common misunderstanding: Evolution is a process that we use to describe FAVORABLE changes that accumulate in a species. These changes are random

87

I give you…

          THE TIGON

A mammal on the verge of speciation.

Lion’s and Tigers are considered to be different species according to your definition. Can’t reproduce together.

Except it happened. A Lion and a tiger in captivity in California successfully mated and produced a “Tigon” (which in turn was subsequently able to reproduce.) Later it turns out that both the Lion and the Tiger were captured within 500 miles of each other in Burma. This fluke of luck suggests that Lions and Tigers may not have completely speciated, snd some limited interbreeding may still be possible. Though I’m not a scientist this sounds to me a lot like this “Allele Drift Cline” crap …er I mean the empirical evidence of interbreeding along clines excluding the extremes you’ve been looking for.
I saw the whole thing on the Animal Channel right before emergency vets so it must be true, right? If you promise me the tupperware I’ll take the time to fully document this. (That means I’ll drink beer and watch the animal channel 24/7 until the show comes on again,then tape it. (Hey maybe I could just put “Tigon” into Alta Vista and find the info there! Nahhh, I’ll do it the way I get to drink beer.)

If that doesn’t work call up the Cornell University Marmot Monax (Groundhog) lab. They’ve been studying the same kind of thing amongst Groundhogs and their kin worldwide (and there are a lot of varieties, with varied degrees of interbreedability.) I learned all this in part due to my exhaustive research into Groundhog extermination. See my topic in GQ if you care. (No piracy intended.)

I hate it when people present partial evidence or “I Heard” and don’t back it up. I apologize for doing the same. To me the evolution of mammals is inherently obvious, so I can’t get really enthusiastic about trying to prove it, but rather present two potential avenues to one so inclined.

88

To alsmith

Thanks for backing me up on the dog/wolf and cat/serval point. I didn’t know that the tiger and the lion could mate and produce viable progeny. Thanks!

Eric

89

And speaking of “I heard”,

I heard that the lion/tiger crossbreed was called a “Liger”, not a Tigon. I also heard that Ligers couldn’t reproduce with other Ligers, but they COULD reproduce with pure lions or pure tigers. Nothing was mentioned about the ability of a 3/4 lion-1/4 tiger to reproduce with a lion, a tiger, a liger, or anoter 3/4 lion-1/4 tiger.

And I read this a few years ago on a Usenet newsgroup, so IT must be true!

90

tracer:

The liger/tigon difference is analogous to the mule/hinny situation. The difference is which species is the stud and which is the dam.

That being said, I have no idea whether a tigon has a lion father or mother.

91

For what it’s worth the Tigon in question had a Lion for the father, and a Tiger for the mother (both families were embarassed and ostracized by their peers in their respective communities but what can you do? They were kids and they were in love. There’s still a lot of intolerance out there you know.)

The Tigon was supposed to be sterile, so they didn’t “fix” it. It was a male. It’s keepers were very surprised when it produce offspring. I don’t recall if they were Tiligers or Litigons, but they made a big deal about them being the first of their kind.
I found an unrelated picture of a “Liger” here:http://geocities.com/Heartland/Ranch/2211/buttonsanimals.html.

Here;'s another: http://www.giccs.georgetown.edu/~dan/jenn/personal/pic99.html

Ewiser:
Glad to help

92

Clearly this is proof.

Of something.

93

Phaedrus, I don’t know if I missed it or what, but did you explain why you feel that mammals are resistant to evolution? What is it about mammals that makes you believe they didn’t evolve like other creatures? Is it something from the fossil record, or a religious belief, or what?

Sorry if you already explained this, feel free to just refer to another post if you don’t want to type in the stuff again.

Thanks,
Revtim

94

Very interesting. For the moment I am involved in a court case where the outcome is highly determinative by my involvement. Jury selection is this week and trial next week. I haven’t practiced law in ten years and I am just an ancillary feature in this trial. Yet I am expected to do MY part. IF I fail in preparing the defendant for taking the stand they might get a lot of time in a not so nice place.

I have been writing answers to previous posts which now look like they have to be scrapped, thanks guys! :wink:

I have a quick question for both of you though. Both of you appeared out of nowhere and then came straight to this thread though ewiser’s route was more direct (only posts on the board are on this thread) alsmith had a total of 33 posts to date. This thread was hidden behind several pages and it would be unusual for this to happen. I am not drawing any conclusions just yet but I DO want your answer to THIS quesiton.

I will address all issues A.S.A.P.
Yours,

Ken

For what a man had rather were true he more readily believes.

95

A <a
href=“http://www.umich.edu/~newsinfo/Releases/2000/Jan00/r011000b.html”> new study suggests big bang theory of human evolution.</a> While not strictly a refutation of any point made, it does bear on the subject of evolution, and mammals, specifically man.

<P ALIGN=“CENTER”>Tris</P>

“Stoning non conformists is part of science. Stoning conformists is also part of science. Only those theories that can stand up to a merciless barrage of stones deserve consideration. It is the creationist habit of throwing marshmallows that we find annoying.”
– attributed to **Dr. Pepper **

96

Ewiser,

You wrote:

Good point. This however is not evolution via natural selection, per se. If anything it suggests an alternate mechanism.

I disagre. Extending the metaphor; let’s say that every time one of our billion machines makes a move that takes it farther away from a solution, it stops making moves altogether (i.e. it dies). This will not make the solution more likely. In fact, the solution becomes less likely, which was one of the scattered points I made.

I know, but I thought I was being generous, since the vast majority of complex organisms have evolutionary cycles which are much slower.

I understand, but the question is really, in the course of one day how many progressive evolutionary steps does an E. coli make? What you are referring to is biodiversity.
Phaedrus,

You wrote:

I don’t see how this is relevant. Is this some kind of lawyer trick to cast dispersions on the credibility of the witnesses? [wink]

97

Phaedrus:

Draw what conclusions you would. You will never glean my sinister motivations until it is too late! (pause here for my maniacal laughter)

Seriously, a fair question. I have been a Straight Dope reader for years, but never posted here, until the mailbag question about evolution last week. (I had a really cool username picked out but typoed my email address, so my password got sent into the void. I guess that means I’m stuck being myself.) I also posted a question I’d mailed Cecil about Groundhogs which he chose not to answer. I was surprised about the overall excellent quality of the responses, and have been having fun and learning since.
As to how I found this thread. It actually shows up in the first page of Great Debates. THey appear to be sorted by most recent post. I would be glad to take a screenshot and post it, if you can tell me how to do that. I am new here, so with respect may I ask you are curious as to my origins? Is there something I’m missing?

98

Isn’t the litigon the particle mediating litigation? I’m sure Phaedrus is emitting many litigons in his current endeavors.

99

For JoeyBlades:

(Quote)________________________________
Good point. This however is not evolution via natural selection, per se. If anything it suggests an alternate mechanism.

If you consider the animals (all organisms for that matter) transitional, since they are, then it does make sense from an evolutionary perspective. These species of animals then become examples of two species that have diverged. We classify them as two different species but since they still retain the ability to mate and produce progeny, we can show that they were at one time related and they are now separating.

I would be VERY interested in any alternative mechanisms you had to explain this event though.

(Quote)________________________________
I disagree. Extending the metaphor; let’s say that every time one of our billion machines makes a move that takes it farther away from a solution, it stops making moves altogether (i.e. it dies). This will not make the solution more likely. In fact, the solution becomes less likely, which was one of the scattered points I made.

Here you run into the limitation to your analogy. There is no “solution” to evolution. To paraphrase the explanation that I made on evolution earlier, it is just the accumulation of survival enhancing traits. No end point or correct solution is possible or even postulated, merely survival enhancing and non-enhancing changes.

(Earlier quote)_____________________________
How do we know that organisms that had a clear competitive advantage didn’t die out while inferior organisms thrived due to sheer luck? How do we know the variations are random? How do we know that just because some organisms evolve, that all of them do? How do we know that organisms evolve indefinitely? Perhaps they evolve to a point and then begin to ‘devolve’… There are things in the evolutionary tree that seem to defy explanation, with respect to natural selection.

The first of these answers is simple. Sheer luck has a ton to due with which organisms thrive and which ones don’t. To help counter this, the organisms evolve so that they can extend their range. That way an event that would have threatened the entire species now only threatens a portion of it.

The variations are random. The easy part of this is the random mating of two organisms. Which male and female will mate can only be predicted in part. The actual event cannot be. To say that the dominant male and the females will reproduce (mostly for mammals) cannot describe which male will become dominant. The allelic frequency changes are almost totally random. The genetics of this is quite complicated (entire books have been written about it). I will briefly discuss sexual reproductive methods since it seems to be where the board is focused but keep in mind there are other mechanisms involved as well. Cross-over is an event where genes will randomly switch their location in the DNA. This, as you might expect, can cause a change in the overall phenotype of the progeny organism. I say that his event is random the propensity for each ‘gene’ and the total number of events during different replication is highly variable and doesn’t have any discernable pattern. There are several other events that take place to increase the randomness of this system. How the chromosomes line up for division influences which set of chromosomes goes to which daughter cell (we have two of each chromosome one from dad and one from mom). So for 26 six chromosomes you can have 27 different combinations for how many of the fathers vs. mothers chromosomes end up in the haploid reproductive cell. Let’s not even get into mitochondrial DNA, co-dominant expression of genes and jumping genes.

Evolution (as mentioned before) is just the change in the genes in a population over time. That’s it. All organisms studied to change from generation to generation. Nobody is static. We know this through long years of study.

We don’t know that they will evolve indefinitely. Some don’t and die out; others do and still die out. What evolution does is gives us the ability to help predict what has happened and what might happen. Who knows what will happen in the future?

I love ‘de-evolution’! De-evolution is still evolution. It is one of those concepts given to us by Star-Trek science fiction writers. But to seriously answer the question, if conditions in the environment shifted to favor characteristics that a species had evolved past, they would probably adapt to the changing environment, and it is possible that they would ‘de-evolve’. It is equally possible that they would find another route of adaptation.

Evolution is only a theory. It has some of the answers that scientists are looking for and it is true that there are things that cannot be explained using it (like the common descent theory) but it is the best we have right now. I don’t know the evolutionary tree all that well, but if you gave me some specifics I could do what any scientists would do - speculate.

I know, but I thought I was being generous, since the vast majority of complex organisms have evolutionary cycles which are much slower.

I understand that most organisms have long generation times, but I don’t know if all of the complex organisms started as complex organisms, meaning that they may not have always had long generation times. What I am trying to get at is, there is an incredible selective pressure for these organisms to change in response to changing conditions and only the ones that do it best will have children. These children are also under this pressure. They will have the advantage of the last generation but only the ones that are best adapted will have children themselves.
I understand, but the question is really, in the course of one day how many progressive evolutionary steps does n E. coli make? What you are referring to is biodiversity.

E. coli makes an evolutionary change with EACH generation, just like all other organisms. Bio-diversity is something else altogether. It basically says that the amount of life on the planet is diverse.

For Phaedrus.

I am what you would consider a newbie to this site. I haven’t really posted here before (although I occasionally lurk) and found the topic to be interesting.

Your implication that I am someone else posting under a different name is cute though :slight_smile: If you would like more information about me personally, let me know as I have no real objection to telling you. I just think the space would be better used on relevant issues.

Eric

100

Sorry about the last answer there. Word didn’t copy the seperator for your question. For the sake of clarity here is the quote:

I understand, but the question is really, in the course of one day how many progressive evolutionary steps does E. coli make? What you are referring to is biodiversity.

The part below that is my answer.

Eric