Zachriel: If urbilateria was segmented, which now seems likely, then segmentation was probably inherited into the various phyla, and the Cambrian diversification of body plans is more easily explained.

Guts: Which has nothing to do with parallel evolution or incremental adaptation as you initially claimed.

The question is whether segmentation evolved more than once in different lineages, that is, parallel evolution.

Zachriel: In any case, my sentence is clear. Evolutionary theory *predicts* that taxa that share a common ancestor will also share many genes and other structural similarities.

Guts: Uhh, that wasn't your sentence. lol you completely changed it. Your sentence was:

Zachriel: As vertebrates and insects share a common bilaterate ancestor, it is *expected* that many genes involved in developmental differentiation will be shared

The rewording is more general, and strictly emcompasses the preceding statement. It is a valid statement of the Theory of Evolution.

Guts: However, despite the fact that the thought was that vertebrates and insects share a common ancestor…

Yes, they do share a common ancestor.

Guts: …it was thought that genes involved in segmentation arose independantly.

That was one tentative hypothesis based on developmental studies.

Guts: So it could have gone either way, if it evolved independantly, that wouldn't have been a failed prediction of evolutionary theory, they could still have a common ancestor and have features that are derived.

That is correct. It would not falsify the Theory of Evolution either way. That's because it's not entailed as a consequence of theory. It's a historical question.

So that returns to my original statement. As vertebrates and insects share a common bilaterate ancestor, it is *expected* that many genes involved in developmental differentiation will be shared. But the data on segmentation has been unclear until the advent of modern genomics. The exact history of these developments is an exciting area of research. Again, nothing teleological about these results.

Not according to what you just stated. It just means that "it would not be a candidate for FLE", but that does not exclude other possible examples.

Of course. The reason why we would go off looking for other examples is precisely because it is inconsistent.

Zachriel:

Um, everything. You seem to consistently confuse theory and data. If urbilateria was segmented, which now seems likely, then segmentation is probably inherited into the various phyla, and the Cambrian diversification of body plans is more easily explained.

Which has nothing to do with parallel evolution or incremental adaptation as you initially claimed. Do you even understand what those terms mean?

Zachriel:

In any case, my sentence is clear. Evolutionary theory *predicts* that taxa that share a common ancestor will also share many genes and other structural similarities.

Uhh, that wasn't your sentence. lol you completely changed it. Your sentence was:

As vertebrates and insects share a common bilaterate ancestor, it is *expected* that many genes involved in developmental differentiation will be shared

However, despite the fact that the thought was that vertebrates and insects share a common ancestor, it was thought that genes involved in segmentation arose independantly. So it could have gone either way, if it evolved independantly, that wouldn't have been a failed prediction of evolutionary theory, they could still have a common ancestor and have features that are derived.

As I showed previously however, what is unexpected is such ancestral complexity.

Guts: No, the traditional conception is inconsistent with FLE, if you disagree, please show otherwise, don't just repeat yourself.

Not according to what you just stated. It just means that "it would not be a candidate for FLE", but that does not exclude other possible examples.

Guts: What exactly does this have to do with parallel evolution or incremental adaptation? The urbilateria is posited to already be segmented.

Um, everything. You seem to consistently confuse theory and data. If urbilateria was segmented, which now seems likely, then segmentation is probably inherited into the various phyla, and the Cambrian diversification of body plans is more easily explained.

Guts: You're still wrong. The entire sentence reads: "As vertebrates and insects share a common bilaterate ancestor, it is *expected* that many genes involved in developmental differentiation will be shared, but the data has been unclear until the advent of modern genomics."

But thats wrong, the thought was that segmentation evolved independantly because of studies with fruit-flies. And in fact many genes involved in developmental differentiation in question are not shared because parts of the genetic program was lost in fruit-flies. Try again.

(Guts, is English your first language?)

In any case, my sentence was clear. Evolutionary theory *predicts* that taxa that share a common ancestor will also share many genes and other structural similarities. Which genes are shared, which are derived and which may have been lost is a question answered by data (i.e. not a deductive consequence of theory). The inheritance of segmentation from a common bilaterate ancestor is well within the evolutionary paradigm. And it certainly doesn't provide any support whatsoever to teleology.

In other words, completely consistent.

No, the traditional conception is inconsistent with FLE, if you disagree, please show otherwise, don't just repeat yourself.

Zachriel:

Do you claim, then, that Eukaryotes *poofed* into existence?

The idea I believe is that the first organisms were bacteria-like.

Zachriel:

It has everything to do with it. That's the nature of evolution. Incremental adaptation.

What exactly does this have to do with parallel evolution or incremental adaptation? The urbilateria is posited to already be segmented.

Guts: Let me remind you what you said:

Zachriel:

"¦ that many genes involved in developmental differentiation will be shared, but the data has been unclear until the advent of modern genomics. The exact history of these developments is an exciting area of research. Again, nothing teleological about these results.

You're still wrong. The entire sentence reads: "As vertebrates and insects share a common bilaterate ancestor, it is *expected* that many genes involved in developmental differentiation will be shared, but the data has been unclear until the advent of modern genomics."

But thats wrong, the thought was that segmentation evolved independantly because of studies with fruit-flies. And in fact many genes involved in developmental differentiation in question are not shared because parts of the genetic program was lost in fruit-flies. Try again.

Guts: If the traditional conception was correct, FLE would have been inconsistent with it, or that it would not be a candidate for FLE.

In other words, completely consistent. Another candidate just as arcane would be required. If you want your notion to have scientific validity, then propose a specific and distinguishing empirical observation.

I note you again didn't indicate whether you accepted my restatement of your position. You responded only to this one point:

Zachriel: * Ancestral Eukaryotes were the result of a long history of evolution, a history which is still largely unknown.

Guts: It is not known if the ancestors of eukaryotes were the result of a long history of evolution. Thats what I said.

Life predates the advent of Eukaryotes by a billion years or more. Genetic evidence, of the very sort you have cited to support your position, indicates that life evolved from a common ancestral population. There is substantial evidence that Eukaryotes were formed by endosymbiosis. But there are large Gaps in scientific knowledge concerning these ancient events. Do you claim, then, that Eukaryotes *poofed* into existence?

Zachriel: I know precisely what I said, and why. The Theory of Evolution *predicts* that new structures will be modifications of existing structures. That doesn't preclude parallel evolution.

Guts: This has nothing to do with new structures being modifications of existing structures. This has nothing to do parallel evolution.

It has everything to do with it. That's the nature of evolution. Incremental adaptation.

Guts: Let me remind you what you said:

You left off part of my sentence.

Zachriel: As to your cite to Stollewerk et al., again, we *expect* that later functions will be modifications of earlier functions. As vertebrates and insects share a common bilaterate ancestor, it is *expected* …

… that many genes involved in developmental differentiation will be shared, but the data has been unclear until the advent of modern genomics. The exact history of these developments is an exciting area of research. Again, nothing teleological about these results.

Many, not all. And it requires data to determine which ones (i.e. it's not entailed as a consequence of theory). Try reading my statement again, for content this time.

Of course. Some versions of front-loading are completely consistent with the Theory of Evolution but have an undetectable, extraneous entity. The data is consistent with Last Thursdayism, too.

If the traditional conception was correct, FLE would have been inconsistent with it, or that it would not be a candidate for FLE. Note this is the umpteenth time I've said this without a response from you, I see that now you're copying and pasting past erroneous paragraphs.

Zachriel:

* Ancestral Eukaryotes were the result of a long history of evolution, a history which is still largely unknown.

It is not known if the ancestors of eukaryotes were the result of a long history of evolution. Thats what I said.

Zachriel:

I know precisely what I said, and why. The Theory of Evolution *predicts* that new structures will be modifications of existing structures. That doesn't preclude parallel evolution.

This has nothing to do with new structures being modifications of existing structures. This has nothing to do with parallel evolution. Let me remind you what you said:

As to your cite to Stollewerk et al., again, we *expect* that later functions will be modifications of earlier functions. As vertebrates and insects share a common bilaterate ancestor, it is *expected*

At the time, scientists did not "expect" any such thing because vertebrates and insects share a common ancestor. The arguments at the time supported independant evolution of segmention. It was because of work with spiders that the idea of a shared origin gained prominence, although still a tentative conclusion that is constantly being reinforced.

Zachriel: Meanwhile, I restated what I thought constituted your argument. You chose to ignore it.

Guts: No you made a strong assertion where none should be made.

Huh? I restated your position. Restating someone's position and asking for verification is an important method of avoiding extraneous disputes over semantics or wording. Is this, or is this not, the basis of your understanding of the data?

* Ancestral Eukaryotes were complex. Agreed.
* Ancestral Eukaryotes had Ancestral HD (homeodomain proteins). Agreed.
* These early HD may have been important in communication between individual cells. That is the reasonable conjecture of the paper that MikeGene points to in this thread.
* These Ancestral HD evolved and diversified for multicellular functions. Agreed.
* Some of the Ancestral Eukaryotes lost HD in later lineages. Agreed.

Do you accept, or do you reject, these additional comments.

* Ancestral Eukaryotes were the result of a long history of evolution, a history which is still largely unknown.
* We don't know if other Proto-Eukaryotes existed, with or without HD, that did not leave modern descendents.

Zachriel: You don't read very well. We *expect* that later functions will be modifications of earlier functions.

Guts: You said this in the context of the segmentation paper, which means you're still wrong, the expectation was not a "modifications of earlier functions" because insects and vertebrates share a common ancestor, but that it evolved independantly.

I know precisely what I said, and why. The Theory of Evolution *predicts* that new structures will be modifications of existing structures. That doesn't preclude parallel evolution. Nor does it tell us precisely when those changes may have taken place. That takes data.

There is substantial evidence that life predates the advent of Eukaryotes, and that Eukaryotes evolved from predecessor organisms. Indeed, this assertion is supported by the very same sort of evidence you cite to support your belief that Eukaryotes were "front-loaded".

Even if that is correct, so what? Thats irrelevant.

Zachriel:

No, you didn't. Meanwhile, I restated what I thought constituted your argument. You chose to ignore it.

No you made a strong assertion where none should be made. It's something you regularly do.

Zachriel:

You don't read very well. We *expect* that later functions will be modifications of earlier functions.

You said this in the context of the segmentation paper, which means you're still wrong, the expectation was not "modifications of earlier functions" because insects and vertebrates share a common ancestor, but that it evolved independantly. The only modification of earlier functions that ocurred here was loss of part of a shared genetic program.

Zachriel:

Which functions orginated in which lineages is a historical question that can be difficult to unravel. That's why we propose hypotheses and then test them.

In this case it's not difficult, it's very unlikely that they evolved independantly in different groups.