Living Fossils

Jerry Smith · #1 10th June 2002, 10:26 PM

Nick, in another thread, said:

Nah, it's been much longer than that. Some creatures have remained essentially unchanged since their first appearance in the fossil record. Heck, they've remained apparently unchanged even through all those cataclysmic puntuations in punk eek.

To which, I responded:

I call. List three or four of the best known species that have remained apparently unchanged for at least 10 million years. Lets discuss them. Lets see if they are the exceptions or the rule, and if it turns out they are the exception, lets see if we can figure out a reason why.....

After all, if some orgnanisms change significantly over 10 million years, and others do not, an explanation is needed right? Or do we just take that opportunity to throw out 100 years of research and get a pat on the back from Brother Gish?

Nick replied with three examples:

1. Coelacanths (360-400 million years)

2. Horseshoe crab (250 million years)

3. Cyanobacteria (over 3 billion years)

Along with some rhetoric that is best left un-repeated. He didn't discuss whether they are the exceptions or the rule. He just asked me to identify the "irony".

I will get this out of the way first, since it is basically irrelevant. The irony is that at least two of the three organisms he mentions (the Coelacanths & the Cyanobacteria), are descended directly from organisms that were related to ones that played key roles in evolution. The further irony is that Nick probably thinks this puts evolution in a bad light - possibly because he has been taught that an ancestral line must go extinct before another line can diverge from it.

Next, lets look at some things these three organisms have in common:
1) They are all known as "living fossils". This should be an indication that they are the exception, not the rule, since such a moniker would hardly be appropriate if they were just like every other organism in their long heritage. Nick forgot to discuss this point - perhaps because it makes any further discussion irrelevant. They were posited as examples of stasis, in order to show that they had not undergone macro-evolution. Being the exception, the rule would then have to be divergence from ancestral lines.

2) They are all well adapted to their niches. Cyanobacteria is an extremely simple and extremely efficient photosynthesizer. Even if a thousand lines descended from it to occupy other niches, cyanobacteria should (and does) still survive anywhere there is light and water.
As I understand it, Coelacanths have very little competition in their habitat(I could be wrong about this. If it is important to you, I can look for a reference & let you know).
The horshoe crab just has great natural defenses against predators.
Population genetics allows for oodles of stasis in organisms already well adapted to their niche - provided they stay in the niche and it is not invaded by a stronger competitor.

Are these the only "living fossils"? No, of course not. Are "living fossils" the exception or the rule? They are the exception.

Can a theory be disproven from exceptions to its predictions? Only if the theory predictions are made as universals.

Zadok · #2 10th June 2002, 11:48 PM

Yeah, living fossils.

Let me add some more to that stack.

Crocodiles & Alligators: Some species have changed VERY little. Some have had partial makeovers.

Birds: Living fossils. Transitional forms (with teeth) exist in the fossil record, but bird species beyond the Mezozoic age have changed, while some species have not.

Sharks: Certain species have changed VERY little, while some adapted as bizzare organisms.

These species are better known as "living fossils" than the ones this "Nick" listed at some other point in time.

Jerry Smith · #3 11th June 2002, 12:36 AM

Originally posted by Zadok
Yeah, living fossils.

Let me add some more to that stack.

Crocodiles & Alligators: Some species have changed VERY little. Some have had partial makeovers.

Birds: Living fossils. Transitional forms (with teeth) exist in the fossil record, but bird species beyond the Mezozoic age have changed, while some species have not.

Sharks: Certain species have changed VERY little, while some adapted as bizzare organisms.

These species are better known as "living fossils" than the ones this "Nick" listed at some other point in time.

I was thinking about including Crocs & cycads, because I remembered (wrongly) asking for "4 or 5" examples not "3 or four". When I read back to the original post, I saw that I only asked for 3 or 4, so I guess the three he presented will have to do.

I don't think birds count, because they don't really show stasis over any significant period of time... You have to expose their genes to mammal or reptile protein compounds to even coax them into forming teeth anymore.

Zadok · #4 11th June 2002, 01:17 AM

I don't think birds count, because they don't really show stasis over any significant period of time... You have to expose their genes to mammal or reptile protein compounds to even coax them into forming teeth anymore.

Hmmm...

Yeah, I guess your right.

Zadok · #5 11th June 2002, 01:19 AM

Actually, I take that back.

Very little has changed in large/giant flightless birds.

npetreley · #6 11th June 2002, 05:22 PM

Originally posted by Jerry Smith

The further irony is that Nick probably thinks this puts evolution in a bad light - possibly because he has been taught that an ancestral line must go extinct before another line can diverge from it.

[...]

They are all well adapted to their niches. Cyanobacteria is an extremely simple and extremely efficient photosynthesizer. Even if a thousand lines descended from it to occupy other niches, cyanobacteria should (and does) still survive anywhere there is light and water.

Descent with modification.
Natural selection.

Those are the two cornerstones of the theory of evolution. Evolution needs both, not just one.

I've decided to defect to the other side on this one. So let's measure cyanobacteria by the god of articles on evolution -- the one which basically says something like this: "Our interpretation of the data to show large-scale, progressive, continuous, gradual, and geochronologically successive morphologic change (Sidor & Hopson, 1998) is the definition of descent with modification, which provides compelling evidence for interpreting the data to be large-scale, progressive, continuous, gradual, and geochronologically successive morphologic change (Sidor & Hopson, 1998), which is the definition of descent with modification."

According to the above definition (pick one), descent with modification is progressive, continuous, gradual, and geochronographically successive, otherwise known as "descent with modification." (If you're still confused on this point, see Sidor and Hopson, 1998.)

That poses a problem for cyanobacteria, because it doesn't seem to do any of these.

But we do have a way out. We explain stasis in the fossil record by hypothesizing that descent with modification occurs whether or not selection pressure is applied. Of course, if this were truly happening, we'd see a gazillion of intermediate forms running around today and we wouldn't be so embarrassed by the lack of them in the fossil record. But so far we've successfully avoided this problem by attacking the people who draw attention to it, calling them uneducated creationists who simply haven't read enough of talkorigins to know how everything works, is supposed to work, or should have worked. Anyway, it almost always works. So I suggest we do more of the same if this comes up.

Anyway, that's what we'll say about cyanobacteria. It continues to exist because no selection pressure was great enough to cause its extinction.

One problem down. The next problem is, why didn't it do any modificating, er, that is, modifying? It must have, otherwise we're in a feces load of trouble. We also cannot say that the modifications were never sufficient to survive, because we'd be stuck with 3 billion years that lacks any surviving modifications with descent, which is a real black eye for evolution.

Okay, then we'll say that the selection pressure was not only insufficient to wipe out cyanobacteria, it wasn't great enough to snuff out any of cyanobacteria's descendents, either. So we reason that the descendents were ultimately successful because, well, because they had to be, or else we have no way of explaining what cyanobacteria was doing twiddling its evolutionary thumbs for 3 billion years while everything else was on its way to, well, developing thumbs to twiddle.

Fortunately, we know this is exactly what happened, because the fossil record contains, side-by-side with cyanobacteria, billions of pseudo-cyanobacteria successful in various different niches, none of which in any way competed for the same resources as the cyanobacteria, and....

What? That's not what the fossil record shows?

Okay, new theory. The descendents all died out because they couldn't compete with cyanobacteria. No, no, no, the creationists would have a field day with that. If any organism at all can be shown to have failed to evolve into at least a superior bacteria, fer cryin out loud, especially having been given 3 billion years to get around to doing it, that surely doesn't look good for evolution.

Okay, another new theory. The cyanobacteria had descendents which survived due to selection pressures, which favored the descendents more than...shoot, that doesn't explain why cyanobactera is never selected out.

Okay, this time for sure. Yet another new theory. The cyanobacteria DID have descendents with modification, but the modifications that survived had these things in common:

1. They always immediately developed the ability to scurry away from the cyanobacteria habitat, really fast.
2. They wanted to scurry away really fast because they could only survive in an environment other than where the cyanobacteria lived.

This explains why we don't see them in the fossil record along with cyanobacteria. The mutations quickly scurried away and thrived somewhere else. We'll probably dig up those fossils someday. In fact, we probably already have evidence of these descendents. I'll bet we can find a modern bacteria that looks a bit like cyanobacteria. We'll label it as one of the descendents of cyanobacteria, call it proof of evolution, and that's that. Case closed, you uneducated creationists.

In fact, I think I've got the beginning of a real money maker here. I could write a book called "the blind scurrier" and make millions on the "scurry away with honor" theory of evolution. I'll explain how this technique of evolution probably occurred millions of times, exactly the same exact way for the cyanobacteria, over a period of 3 billion years, producing millions of related strains that developed every which way (note to self: the original mutation could not occur EXACTLY the same way -- better toss in a few variations for credibility, but remember to keep the two traits constant or else the theory doesn't work).

The "scurry away with honor" is perfectly consistent with the fossil record. It explains why there is no recognizable fossil record of any of these descendents anywhere nearby cyanobacteria. They simply scurried too fast to leave any trace of their history. In fact, these descendents would have remained entirely undiscovered had it not been for a recent study that shows that strep, yeast, and the fungus that causes jock itch all share vowels with the word "cyanobacteria", a correlation which proves common descent.

Yeah, that's the ticket. I'm-a goin' really good now, boss. Mover over, Gould, punk eek is history.
"Scurry away with honor" is where evolution is at today.

(Note: Thanks to the clever writers of the Angry Beavers cartoon for the expression "Scurry away with honor." )

LiveFreeOrDie · #7 11th June 2002, 05:47 PM

Originally posted by npetreley
According to the above definition (pick one), descent with modification is progressive, continuous, gradual, and geochronographically successive, otherwise known as "descent with modification." (If you're still confused on this point, see Sidor and Hopson, 1998.)

That poses a problem for cyanobacteria, because it doesn't seem to do any of these.

Why is this a problem? I don't see the word "mandatory" in the definition of DWM.

But we do have a way out. We explain stasis in the fossil record by hypothesizing that descent with modification occurs whether or not selection pressure is applied.

No, we explain stasis by hypothesizing that the selective pressures on a given species remained relatively constant.

Anyway, that's what we'll say about cyanobacteria. It continues to exist because no selection pressure was great enough to cause its extinction.

One problem down. The next problem is, why didn't it do any modificating, er, that is, modifying? It must have, otherwise we're in a feces load of trouble. We also cannot say that the modifications were never sufficient to survive, because we'd be stuck with 3 billion years that lacks any surviving modifications with descent, which is a real black eye for evolution.

Again, why is this a problem? Where does evolutionary theory say that a species must evolve.

Okay, then we'll say that the selection pressure was not only insufficient to wipe out cyanobacteria, it wasn't great enough to snuff out any of cyanobacteria's descendents, either. So we reason that the descendents were ultimately successful because, well, because they had to be, or else we have no way of explaining what cyanobacteria was doing twiddling its evolutionary thumbs for 3 billion years while everything else was on its way to, well, developing thumbs to twiddle.

Where in evolutionary theory does it say that evolution is "on its way" anywhere? It's only human arrogance that places us at the "top" of some evolutionary chain. The fact is, on a sheer biomass basis, bacteria have always and will forever dominate all other forms of life on Earth.

Fortunately, we know this is exactly what happened, because the fossil record contains, side-by-side with cyanobacteria, billions of pseudo-cyanobacteria successful in various different niches, none of which in any way competed for the same resources as the cyanobacteria, and....

What? That's not what the fossil record shows?

Okay, new theory. The descendents all died out because they couldn't compete with cyanobacteria. No, no, no, the creationists would have a field day with that. If any organism at all can be shown to have failed to evolve into at least a superior bacteria, fer cryin out loud, especially having been given 3 billion years to get around to doing it, that surely doesn't look good for evolution.

Okay, another new theory. The cyanobacteria had descendents which survived due to selection pressures, which favored the descendents more than...shoot, that doesn't explain why cyanobactera is never selected out.

Okay, this time for sure. Yet another new theory. The cyanobacteria DID have descendents with modification, but the modifications that survived had these things in common:

1. They always immediately developed the ability to scurry away from the cyanobacteria habitat, really fast.
2. They wanted to scurry away really fast because they could only survive in an environment other than where the cyanobacteria lived.

This explains why we don't see them in the fossil record along with cyanobacteria. The mutations quickly scurried away and thrived somewhere else. We'll probably dig up those fossils someday. In fact, we probably already have evidence of these descendents. I'll bet we can find a modern bacteria that looks a bit like cyanobacteria. We'll label it as one of the descendents of cyanobacteria, call it proof of evolution, and that's that. Case closed, you uneducated creationists.

In fact, I think I've got the beginning of a real money maker here. I could write a book called "the blind scurrier" and make millions on the "scurry away with honor" theory of evolution. I'll explain how this technique of evolution probably occurred millions of times, exactly the same exact way for the cyanobacteria, over a period of 3 billion years, producing millions of related strains that developed every which way (note to self: the original mutation could not occur EXACTLY the same way -- better toss in a few variations for credibility, but remember to keep the two traits constant or else the theory doesn't work).

The "scurry away with honor" is perfectly consistent with the fossil record. It explains why there is no recognizable fossil record of any of these descendents anywhere nearby cyanobacteria. They simply scurried too fast to leave any trace of their history. In fact, these descendents would have remained entirely undiscovered had it not been for a recent study that shows that strep, yeast, and the fungus that causes jock itch all share vowels with the word "cyanobacteria", a correlation which proves common descent.

Yeah, that's the ticket. I'm-a goin' really good now, boss. Mover over, Gould, punk eek is history.
"Scurry away with honor" is where evolution is at today.

(Note: Thanks to the clever writers of the Angry Beavers cartoon for the expression "Scurry away with honor." )

Woo hoo! Hey, Nick can attack his own straw men!

Your antics prove nothing Nick, and pretty much remain the equivalent of intellectual masturbation. Maybe you enjoy it but I'd rather not have to watch.

Jerry Smith · #8 11th June 2002, 05:56 PM

Descent with modification is defined, if the phrase needs a definition, is reproduction with change.

Evolution is descent with modification, and its effects are constrained and directed by natural selection.

This has been observed consistently in nature.

Common descent is the inference that evolution can be responsible for the diversity of life present on earth today.

Large scale progressive morphological changes in fossils chronologically over geological time, then, is evidence that Common descent is an accurate inference.

Scurry Away with Honor is closer than you may think to the way speciation events occur - events that lead to isolation between two populations permitting a divergence onto different evolutionary paths. However it is often the case that small changes that are not expressed in an overall gene pool can be carried to the new habitat, where only those few that are homozygous for a particular mutation that is adaptive to the new niche will thrive.

Cyanobacteria may have had no descendants that survived as individual organisms. Evolution of cyanobacteria and other prokaryotes may have been characterized by different processes that are certainly over your head if the simple ones like natural selection are. I won't go into them.

randman · #9 11th June 2002, 06:50 PM

Where are the intemediaries today? If the whole species did not evolve but small, isolated groups, then surely there should be more living intemediaries around.

Where are they?

They are not even in the fossil record.

Jerry Smith · #10 11th June 2002, 06:56 PM

Originally posted by randman
Where are the intemediaries today? If the whole species did not evolve but small, isolated groups, then surely there should be more living intemediaries around.

Where are they?

They are not even in the fossil record.

Back to the "no transitional fossils" lie, eh randman?

How do you know there are no living intermediates around? What makes you so sure bonobos aren't intermediate between Chimpanzees and some future chimpanzee derived line?