BREAKTHROUGH OF THE YEAR: Evolution in Action

Science ^ | December 2005 | Elizabeth Culotta and Elizabeth Pennisi

[CarolinaGuitarman]

"So then their was an intelligent creator? The one that created the first spark of life that may or may not have had successive minimal evolutions over time?"

I didn't say that either. But I know of nobody claiming life came from nothing.

[MEGoody]

Ah, so what they really mean is that there are 4 million differences between chimp and human DNA, not that there were 4 million evolutionary events.

[Antoninus]

Through the use of an inane analogy and a complete lack of any actual information regarding your position.

Yawn. You dogmatic Darwinians are a tiresome lot. I believe that the ToE is a compelling explanation of the development of life. However, I don't believe it can be elevated to the status of scientific law--nor have its adherents answered many of the tough questions that have been proposed of late.

When you have to depend on men in robes to enforce your scientific orthodoxy, something is deeply wrong.

[narby]

I find it reasonable to accept the idea that the current populations derived from original pairs. I do not find the idea that the current populations derived from eons of evolution wherein life began from non-life to be reasonable.

Actually, the folks studying species extinction say that about 8 pairs are required for any species to survive. For example they brought back the Condor with a dozen or so individuals.

I'm not sure why this is necessary, but I assume to prevent harmful mutations from becoming the norm. Like the old saw about not marrying your sister.

This is one of the problems with the story of Noah. Saving two of every species just wouldn't work.

[narby]

I believe that the ToE is a compelling explanation of the development of life. However, I don't believe it can be elevated to the status of scientific law

A scientific "theory" is as high as it gets in science. A scientific "law", like Ohm's law, is usually simple formulas, while theories are descriptions of processes that can be quite complex.

If we found exceptions to a scientific law, then it would be broken and discarded. But because theories are more complex, parts of them can be invalidated, or added to, without breaking the entire theory.

When you have to depend on men in robes to enforce your scientific orthodoxy, something is deeply wrong.

Evolution is mostly conducted in the realm of science. The Dover case and a couple of others are the rare exception required to protect the science.

On the other hand, ID is conducted solely in the public square, in politics and the courts. They have conducted zero actual original science on their own, and have yet to even propose tests for things like how ID would be falsified.

Since ID totally depends on "men in robes" and elected officials, something is deeply wrong with it.

[Condorman]

They look pretty good to me, all artists have a few unique abstract works.

Your original claim in post 31 was "ALL animals and humans are so symmetrical." Now that you have seen this is not the case (see also sponges, coral, most gastropods, and the digestive tracts and cardiovascular systems of ALL amphibians, reptiles, fish, birds and mammals), we have a new universal law about artists. How many other generalizations do you plan to toss out (and just as quickly abandon) in your haste to establish "design?"

[Tailback]

Great book. Pournelle and Niven write some excellent stuff.

[Antoninus]

Evolution is mostly conducted in the realm of science. The Dover case and a couple of others are the rare exception required to protect the science.

That sounds very similar to what various bishops told Gallileo. Science doesn't need "protection" from a guy in a black robe. Let the theory be questioned and let the proponents of the theory defend it without "devolving" into ad hominem invective. The fact that the pro-ToE crowd has been unable to refrain from attacking the motives and the persons of their questioners is the primary factor which makes me think that the ID people may be on to something.

[P-Marlowe]

At some level every discovery in biology and medicine rests on it, in much the same way that all terrestrial vertebrates can trace their ancestry back to the first bold fishes to explore land.

Fishes?

We can trace our ancestry back to fishes?

Does someone have a copy of the pedigree?

Does anyone have a picture of the family tree?

Or is this all pure speculation?

[Antoninus]

Here's one of my major problems with the ToE as it is currently formulated:



How is it that an organism like this can remain almost wholly unchanged for 140 million years? Is it not subject to genetic drift like everything else on the planet?

[Senator Bedfellow]

How is it that an organism like this can remain almost wholly unchanged for 140 million years? Is it not subject to genetic drift like everything else on the planet?

Sure it is, and of course the modern coelacanth is not the same species as the ancient fish - it has changed slightly since then.

Why not more change? If you're already well-adapted to your environment, and the environment doesn't change, then it becomes increasingly likely that any change will make you less well-adapted, and such changes will be selected against. So therefore, creatures that stick with the tried-and-true body plan will preferentially survive over radical newcomers who are less well-adapted, resulting in organisms that don't appear to change much over time.

It's not just coelacanths, either - sharks, cockroaches, dragonflies, ferns, and lots of other things haven't changed much in the last hundred million years either. If you have something that works, there's a strong incentive not to change.

[Antoninus]

Sure it is, and of course the modern coelacanth is not the same species as the ancient fish - it has changed slightly since then.

Proof of that? I thought that the main criterion for speciation was the ability of creatures to mate and produce viable offspring. As there is no way for a modern coelacanth to be paired with one that's 140 million years old, such an observation is speculative at best. By appearance alone, one is forced to conclude that the species has remained practically identical to its fossilized progenitors.

Why not more change? If you're already well-adapted to your environment, and the environment doesn't change, then it becomes increasingly likely that any change will make you less well-adapted, and such changes will be selected against. So therefore, creatures that stick with the tried-and-true body plan will preferentially survive over radical newcomers who are less well-adapted, resulting in organisms that don't appear to change much over time.

I've heard that argument before, but it doesn't answer the question of why this creature in particular, was not subject to the genetic drift that seems natural in almost every other species.

It's not just coelacanths, either - sharks, cockroaches, dragonflies, ferns, and lots of other things haven't changed much in the last hundred million years either. If you have something that works, there's a strong incentive not to change.

I appreciate that argument, and it may be true in the cases of all the creatures you mention above. However, the coelacanth is not exactly a model of evolutionary success that may be found spread over the whole world in vast numbers. In fact, they don't seem to be very successful at all, consigned as they are to a few tiny colonies.

In this case, you must argue either a.) the coelacanth has managed to exist into modern times because it is perfectly adapted to the few tiny environments in which it is currently found and has been able to maintain this for over 140 million years without any competitors or predators forcing it out (actually 400 million, but what's a few hundred million years between friends?). Or b.) there are actually large undiscovered populations of coelacanths scattered throughout the world, making it a fantastically successful species similar to sharks and cockroaches.

[CarolinaGuitarman]

Not only is the modern coelacanth not the same species as the ancient ones, it's a different genus entirely. It has changed; there just has been any great selective pressure to change drastically. Organisms like the coelacanth and the shark are exceptional anyway.

[narby]

Science doesn't need "protection" from a guy in a black robe

Science doesn't need protection from science. It needs protection from politicians such as those in Dover and Kansas that seek to impose non-science.

The fact that the pro-ToE crowd has been unable to refrain from attacking the motives and the persons of their questioners is the primary factor which makes me think that the ID people may be on to something.

The liars on the Dover school board are what they are. They are the ones who expressed their motives to promote Christianity in public schools, and then lied about it on the witness stand. And lied again about how the money for the Pandas book came to be raised.

If you don't like being on the side of proven liars, it's not my fault.

[PatrickHenry]

How many other generalizations do you plan to toss out (and just as quickly abandon) in your haste to establish "design?"

What's the problem here? We've got a guy who claims that: (a) symmetry is God's signature; and (b) the absence of symmetry is an example of God's flourishes. Neat. Bullet proof. He lives in a world that never fails to "prove" his beliefs. This seems to be rather primitive theology, but he's happy with it.

[narby]

Here's one of my major problems with the ToE as it is currently formulated:

The Coelacanth is a classic stawman. Merely because creatures can evolve doesn't mean that they must.

[Antoninus]

Not only is the modern coelacanth not the same species as the ancient ones, it's a different genus entirely. It has changed; there just has been any great selective pressure to change drastically. Organisms like the coelacanth and the shark are exceptional anyway.

Proof of that? Dropping fossilized ancient creatures in a particular taxonomic classification is a completely academic exercise. Of the articles I've read claiming that the modern coelacanth is different from ancient ones, none has posited such a great variance as you have offered. The more convincing ones suggested that the differences may be more subtle--like improvements in the immune system.

However, it should be pointed out that variances exist within human immune systems as well, which is why certain pathogens can decimate a population in one area of the world, and have no effect in another. No one would argue, however, that a European who gets sleeping sickness is not the same species as an African who doesn't. Alright, perhaps a late-19th century social-Darwinist might.

[Antoninus]

The Coelacanth is a classic stawman. Merely because creatures can evolve doesn't mean that they must.

No, it's not. I have yet to hear anyone come up with a truly convincing theory as to why it didn't.

[Senator Bedfellow]

By appearance alone, one is forced to conclude that the species has remained practically identical to its fossilized progenitors.

"Practically identical" is not a particularly useful designation. The modern coelacanth has scales of a different shape than the ancient coelacanth, the pelvic and dorsal fins are in a different place skeletally, and of course, the ancient coelacanths topped out at about fifteen inches - modern coelacanths are over four feet long.

I've heard that argument before, but it doesn't answer the question of why this creature in particular, was not subject to the genetic drift that seems natural in almost every other species.

Perhaps I was unclear in my previous answer, sorry. It was subject to genetic drift, just like every other organism. The only difference being that radical changes due to mutations produced by genetic drift resulted in animals that were less well-adapted, so they died out. The coelacanth has experienced genetic drift, resulting in the differences between the ancient fish and the modern one, but the basic plan is well-adapted, so it is selected for and preferentially retained.

However, the coelacanth is not exactly a model of evolutionary success that may be found spread over the whole world in vast numbers. In fact, they don't seem to be very successful at all, consigned as they are to a few tiny colonies.

Defining "success" in such a manner is essentially a value judgement. Wide geographic distribution is not required by the theory of evolution. Organisms that survive and reproduce are "successful" in evolutionary terms - by that standard, the coelacanth is no more or less successful than any other living organism. Coelacanths live in the Indian ocean, grizzly bears live in Alaska, penguins live in Antarctica - in all cases, they're more or less well-adapted to their environments, and they survive and reproduce, making them "successful" in evolutionary terms.

[Antoninus]

I wrote: The fact that the pro-ToE crowd has been unable to refrain from attacking the motives and the persons of their questioners is the primary factor which makes me think that the ID people may be on to something.

You responded: If you don't like being on the side of proven liars, it's not my fault.

Ah, guilt by association, eh? By merely entertaining questions on the ToE, I am "on the side of proven liars."

QED.