Living Fossils, a disproof of evolution?

[TheFiveSolas]

If evolution happens by means of accidental mutations that "change the frequence of alleles" in a "population over time." Why then do we find creatures that are virtually unchanged dating back into the hundreds of millions of years?

For example, the Coelacanth (by no means the only example of this sort) is essentially (as far as shape and bone structure, the same as 300+ million years ago.

"It flourished for more than 300 million years, but was thought to have gone extinct 80 million years ago," said Dr. John McCosker, senior scientist and chair of Aquatic Biology at the California Academy of Sciences...We know that it's an extraordinary fish and its ancestry goes back 380 million years. It hasn't changed that dramatically, at least in external appearance or bone structure..."

http://www.enn.com/features/1999/12/...ossil_7406.asp

What I want to focus on in this thread are two main points:

1) The time-frame for the existence of the above fish goes back @380 million years. Life is said to have arisen @3.5 billion years ago which is only ten times as long as the above time frame.

Note: In one-tenth the time that it allegedly took to go from a "simple" (at the molecular level it is FAR from simple) cell to ALL the various species observed today we find a Coelacanth being changed into a........
Coelacanth!

2) Mutations are alleged to provide the new information for novel functions and structures to arise. Mutations happen due to random copying errors. Therefore, during the 380+ million years of Coelacanth's reproducing we should predictably (according to NDT) find some major changes in the species since copying errors are inevitable. Yet, we find very little change.

Note: Random copying errors are supposed to cause changes, some of which are claimed to bring about new information and structures. In one-tenth the entire time-frame of "goo-to-you" evolution we would predict, if the theory were true, major changes to have occurred.

What gives?

[WinAce]

You do know that the modern Coela is a different genera than the ones going back millions of years ago?

[Socratism]

Today @ 05:04 PM post located here
WinAce:

You do know that the modern Coela is a different genera than the ones going back millions of years ago?

Darn, you beat me to it.

I was going to say that reasons can always be invented to explain anything that the theory would predict because the theory itself does not predict that anything in particular will ever happen.

So any evidence that does not fit the previous subjective rationalizations can always be explained away by another subjective rationalization.

That is whythe only "theory of evolution" (scientific one that is) is the one Dan defined and that one is so trivial it is stretching it to refer to it as a scientific theory.

[RufusAtticus]

If anyone is near Boston, the Harvard Museum of Natural History has a nice display which demonstrates how different the modern coecanths are from the ancient ones.

[Bald Ape]

Socratism,

You do realize there is a difference between a theory that is able to expalin anything that could be found, and a theory which is able explain everything that has been found, don't you? The latter is something all true scientific theories have in common; and it is quite easy to prove via demonstration that all life on the planet is of common descent is not the former:

Find a sequence of nucleotides in human DNA which
1) strongly resembles the genetic code for a viral protein (90% similar)
2) has a near identical copy (90% similar) at the same location in gorillas and
3) has no copy at that location in chimps.
Bam. Common descent falsified. Game over.


Excavate a human skull buried 10 feet deep in the stone at the bottom of the Grand Canyon (you know, amongst all of the fossils of the other vertebrates we supposedly coexisted with 6,000 years ago). Boom. We're done here - time to pack up and go to church.

You honestly sound like you are making the argument that because nobody can seem to find anything that falsifies a scientific thoery, it is not falsifiable. Have you ever stopped to consider the possibility that evolution hasn't been falsified yet not because it's not falsifiable, but rather because it's not false? Just wondering.

[Duvenoy]

For some good info and great pics, go here:

http://www.dinofish.com/testframemain.html

This is the site of a conservation effort dedicated to 'Ol' Four Legs'. Coincidently, I'm wearing a Dinofish tee even as we speak.

So called living fossils are not all that uncommon. Crocodiles, ants and cockroaches saw the dinosaures come and go. Horseshoe crabs are very ancient, as are sharks. The surviving species have all evolved very little. Crocs and sharks have gotten smaller than their ancestors, and most of the stranger species have gone extinct, but beyond that and a diversification of species, they're basicly the same.

I would not consider 'living fossils' (I've never liked that term. It's a contradiction) to be a disproof of the ToE. Rather, the design of the animal was well enough suited for it's ecological niche early in it's history.

Which is not to say that subspices didn't evolve from the coelacanth we know and love. The chances are that they did, but failed to survive. The modern coelacanth is marvelously equiped to do what it does: mainly hang out in deep-water caves.

Do enjoy the Dinofish site.

doov

[Bald Ape]

The theory of evolution predicts that dramatic physiological changes will occur as populations adapt to changing or disappearing ecological niches over long periods of time. If adaptations don't happen quickly enough, or the niche changes or disapperas too quickly, the species will go extinct.

Thus, if the coelacanth were not well adapted to its current ecological niche (deep caves), or if it could be demonstrated that for some extended period in the past 300 million years, this ecological niche did not exist anywhere on earth, AND STILL no dramatic physiological changes occured, TFS would have the grounds to make an argument.

Odd thing is - unless I read his post too fast - I kind of missed him making those points.

[TheFiveSolas]

Bald Ape,

The main problem with your rebuttal is that mutations don't happen due to the organism living or not living in an ecological niche. Mutations happen due to copying errors and therefore occur whether species are "well adapted" or not.

[Rusty T]

But doesn't the evironment determine the success or failure of any changes made by mutation?

[TheFiveSolas]

Tizzi,
Yes, mutations that benefit the organism might have a selective advantage. My point, though was that mutations will occur whether the environment selects them or not. If I remember correctly the known/measured copying error rate (for any particular nucleotide) is on average between about one every billion to ten billion transcriptions. In humans, for example, that would mean that there would, on average, be approximately six nucleotide error for every offspring.

A site that has some interesting details on this can be found at:
http://web.utk.edu/~jwolf2/popgen/10.pdf

[Bald Ape]

But if the ceolacanth has a physiology optimized for its niche in deep caves, any mutations that cause dramatic physiological changes will be deleterious - those organsims which are born with such mutations will not fare as well as their brethren (who also have mutation, but just not ones causing dramatic physiological changes), and thus will not pass on the physiology-changing mutations to their offspring.

Thus, the DNA of today's coelacanth IS vastly different, and many aspects of its physiology are probably subtly different. I just don't see the puzzle here - could you explain it more clearly?

EDIT: Please back up the following [indirectly asserted] premise: There exists a number 'n', such that after 'n' mutations, the skeletal structure of an organism will have changed dramatically (if at all).

Keep in mind
1) changing an adenenine to a guanine, then back to an adenine constitutes 2, not 0, mutations
2) GAT and GAC are translated identically, but are separated by a mutation.
3) The amino acid sequence of a single, small protein in mice (cytochrome c), can be generated by any one of 1 billion, billion, billion, billion different genomic sequences.
4) Many large chunks of DNA exist which seem utterly unaffected by complete removal, much less massive numbers of mutations.

[biter]

I have never understood why someone knowledgible in this topic would use this argument.

There is no requirement that all lineages must experience grand morphological change over time.

There are a great number of things that can or couldchange over time and we would have no way of knowing about it - aspects of cellular physiology, for example. These are things that evolution affects as well, but most seem to be preoccupied with outward apprearance.

And as has been pointed out, "virtually" unchanged does not mean "completely" unchanged.

[TheFiveSolas]

biter:
I have never understood why someone knowledgible in this topic would use this argument.

I don't understand why someone knowledgeable in this topic would deny the inevitability of mutations changing amino acid sequences, in turn changing the proteins produced, necessarily producing changes in the species over time (the greater the time, the more probable the accumulated mutations would cause greater changes.)

In addition, even single point mutations have been observed to produce drastic changes such as in sickle cell anemia.

Therefore, since point mutations (copying errors) are inevitable, it necessarily follows that accumulated point mutations over hundreds of millions of years would drastically change a species.

Also, I won't even go into the problem of genetic drift occuring in small isolated populations.

[TheFiveSolas]

BaldApe:
...the DNA of today's coelacanth IS vastly different...

I'll simply point out that no DNA comparisons have been made, therefore this assertion is utterly without evidence.

Of course, if you find DNA from a creature allegedly several hundred million years old I'll use it as evidence against the old age interpretation. DNA just doesn't last that long, nor anywhere near it.

BaldApe:
Keep in mind
1) changing an adenenine to a guanine, then back to an adenine constitutes 2, not 0, mutations

Such a change would indeed count as two mutations. However, such a "feat" has worse odds than winning the same pick-6 lottery twice. In other words a random point mutation at the same position in the nucleotide sequence has odds in the billions. In addition, changing back to the original nucleotide rather than one of the other three increases the improbability.

BaldApe:
4) Many large chunks of DNA exist which seem utterly unaffected by complete removal, much less massive numbers of mutations.

The key words in the above assertion is "seem uttery unaffected." In addition, such an assertion assumes that certain sequences in the DNA are junk, having no use or purpose whatsoever. However, in a recent issue of Nature* a pseudogene was shown to have a regulatory effect (i.e., it stabilized protein synthesis) on its corresponding gene in another chromosome. In other words, things that were once thought as "vestigial" are turning out to have functions that we didn't realize.

*See the article by Shinji Hirotsune, M.D., Ph.D., Division of Neuro-Science, Research Center for Genomic Medicine, Saitama Medical School, Japan, in the May 1st issue of Nature Note: Hirotsune collaborated with Anthony Wynshaw-Boris, M.D., Ph.D., UCSD associate professor of pediatrics and medicine.

[RufusAtticus]

Today @ 01:59 PM post located here
TheFiveSolas:
The key words in the above assertion is "seem uttery unaffected." In addition, such an assertion assumes that certain sequences in the DNA are junk, having no use or purpose whatsoever. However, in a recent issue of Nature* a pseudogene was shown to have a regulatory effect (i.e., it stabilized protein synthesis) on its corresponding gene in another chromosome. In other words, things that were once thought as "vestigial" are turning out to have functions that we didn't realize.

Have you even read the paper? They did not find a function for a "vestigal" pseudogene, i.e. a unary pseudogene. In fact, what they observed could not occur with unary pseudogenes.

Therefore, since point mutations (copying errors) are inevitable, it necessarily follows that accumulated point mutations over hundreds of millions of years would drastically change a species.

You do remember that modern coelcanths are distinct from their ancient relatives? The idea that they have remained unchanged is a popular myth.