nested heirarchies as evidence against darwinian evolution

By superficial he's referring to the resemblance between separately evolved implementations of the same thing. A good example is the eye. A superficial examination of the mammal and octopus eyes reveals a great deal of similarity, but a more detailed examination reveals that the similarities are superficial. For instance, the blood supply is on the retinal surface in mammals causing a blind spot and decreased sensitivity because of the obstructing blood vessels, problems the octopus eye does not have.--Percy

it's important to note that the mammalian eye is essentially "inside out" indicating two completey different evolutionary paths

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Rand, you are repeating the question again.Percy requested that you address the answers that have been provided in this thread, not simply repeat the question over and over.To wit: You have been answered by bluegenes, Modulous, exon, Lithodid-Man, mark24, me, and Percy.You are treading on thin ice here, I think.Remember, Percy said, "Let's see how it goes".I suggest you stop repeating yourself and rebut the points that have been made.

Hi Molbiogirl,The information you provided is very much appreciated and helpful, but please let moderators issue the warnings. We want to give people the best chance possible within the Forum Guidelines. Thanks!

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--	Percy
	EvC Forum Director

Eh? Only for parasites! New things do pop up. Look at yourself. You can start with a quadruped with a tail, and end up after numerous stages with a tail-less biped. What you call and don't call "new phyla" is largely a matter of our own classification system and terminology.But there's no reason why the last ten/fifteen million years (or whatever takes us back to a primate with a tail) should be replicated. If you don't expect another monkey like creature to become an ape, and then a human, why do you expect invertebrates to keep changing into vertebrates? A mantra? I just made it up in my own words, because it's obvious, and it's because it's obvious that you'll have heard other "evos" saying similar things.I think you'll find that the complex base of the mammalian inner ear evolved only once, but I'm glad you agree that our ears evolved. Their mutual ancestors had "inward" (inner?) organs, teeth, hair etc in common. They both share the basic mammal characteristics with us. The apparent dog like resemblance is superficial, yes, just as the Koala's miniature bear like appearance is.But marsupials filling in niches in the absence of placentals is a good example of the "niche" influencing different lineages in the similar ways, and a classic illustration of natural selection. Exactly, they're both land mammals. Whales have more profound, complex similarities with the dogs than they do with sharks, for obvious reasons.

Well, I guess I will see you guys later because I don't think I've been answered at all. It's pretty simple. My grandfather is dead so of course he isn't having more children. However, more primitive forms still abound, but they aren't giving rise to major forms like the phyla. They did give rise to phyla 500 million years ago. 500 million years is a very long time for that process to end.The fact that the more evolved forms, the phyla, kept evolving according to evos isn't a satisfactory answer. Neither is the answer of competition, and contrary to percy's remark, I answered that.The fact things continue to evolve shows that new forms are not crowded out. If you want to argue the same forms are crowded out, say, no new vertebrates could arise because the existing vertebrates crowded them out, fine. I disagree, but since no studies are available to substantiate the hypothesis, there's not much more we can go on there.However, the competition doesn't explain why new novel forms outside the current phyla would not emerge......why wouldn't, for example, we see all sorts of forms and phyla continuing to prop up from the original types of organisms that evolved the phyla in the first place? Why would there only be one strain so to speak and not new ones developing.Think of it this way. There is a mechanism for planting trees and these trees form evolutionary phylogenies. If the mechanism is in place, wouldn't new trees be started, not just new branches, all the time?Why wouldn't there be?Is the argument all the potential ways have been exhausted for those specific organisms and types of organisms leading to the animal phyla? So now, you cannot have any more evolution from that "stage"? That doesn't make sense if Darwinian evolution is how it occured.Moreover, that suggests evolution is limited by a preset existing range of plans.I would like to see some evos address these points above I have raised. They are very specific and on target here.

Is the mammalian ear then superficial or not?And there are differences in all similar designs between each species right? My eyes are not the same as a cat's eyes. How is that not equally "superficial" based on the definition you give?

Hi all,

quote:

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On apes or whatever for example, if evolution is a random process,
  —randman

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But evolution is NOT a random process.
You haven't learnt anything here, in what, 2 years?.Iasion

Hi all;I'm no following either sides arguments all that well, so perhaps a few of you can clarify them for me.My understanding of biologicdal evoltion is that it is a process of descent from one, or no more than a few, common ancestors. That is, that it is a matter of continuous subdivision of categories from one general category down through several alterations or sub-categories withinn that overall category. This is the notion of 'nested hierarchy'-- am I right.Next, the "Cambrian Explosion" was a geologically brief time period during which, after several billions of years of 'life' subdividing into 'kingdoms'and 'sub-kingdoms, suddenly sprout more subdivisions we call 'phyla. Now, according to the theory these 'phyla' are subdivions of a 'nested hierarchy' within ;'life' which is over 'kingdoms' which is over 'sub-kingdoms' which is over 'phyla' which is over... and so on. Am I right so far?Now, here is where it gets tricky. The darwinian side rejects the argument that something is wrong when the sub-kingdoms, kingdoms, and 'life' [per se] that produced the 'phyla' during the relatively short pre- and post- "Cambriam Explosion" epoch simply shut down and produced no more of them. Indeed, if memory serves, allowed some of the cambriam phyla to go extinct. Now, if the argument is the one darwinians are making, i.e., the 'nested hierarchy' argument, they cannot use it for post-phyla evolution without using it for pre-phyla evolution, and in that case, they cannot use it against randman's argument that pre-phyla nested hierarchies [kingdom, sub-kingdom]should still be generating new phyla, just as they did in the first place. But they do not.The only objection to randman's argument that I can see is extinction. If life still exists, and evidently it does, then some of the 'kingdoms', [or at least some of the 'sub-kingdoms'], that first produced the 'nested' sub-divisions, and were necessary to their generation, the phyla, must themselves have gone extinct at that time, thus shutting down phylum production for good and all.If there is no evidence of whole kingdom or sub-kingdom extinction in the fossil record, then it would appear that randman has a valid point. Which raises the issue that if 'nested hierarchies' were not responsible for the evolution of the the phyla by 'common descent', as 'nested hierarchies' appear to explain post-phyla evolution, into more and different sub-categories , then something else must have been present at that time which no longer exists, or at least, no longer acts. If it exists but no longer acts, that would be quite irrational, so I opt for 'no longer exists', whatever it was. I just can't imagine what it might have been?!?

Maybe looking at this up the ladder a bit can help. Something evolved metozoans according to evos, and then produced the animal phyla roughly during the Cambrian explosion. That was a specific process.Why is that same process not occuring today?Let's call the common metazoan ancestor, Dad, and he has brothers too. Both are capable of evolving, and Dad apparently had children and they evolved into a whole family of phyla.But the thing is Dad, or one of his brothers and cousins, are still having children. It's been over 500 million years since his first batch multiplied to the animal phyla.Where are the next batches?500 million years is a long time for Dad or Dad's brothers and cousins not to have had any more children. Where are they?Now, you say, well, the first batch keeps killing them off so there is no place for them.....nice hypothesis, untested mind you, and I disagree because there is a lot of violatility with Dad's first group, whole major branches are driven to extinction....seems like there is room for more if there was room in the past.But even with that argument, we learn that Dad can produce different sorts of children since all of these children have different mutations....so why wouldn't Dad evolve something superiour to the first batch? The only answer would be if evolution was prescribed.I am not an evolutionist, but Davison was correct on that point.

You stated it better than I could, but that's exactly my argument...thanks for weighing in.

So by your reasoning there should be unlimited phyla and the earth can support an infinite number of species?

"unlimited" is too strong a word to use and poorly designed within a context here. But considering over a fairly short span, we saw an explosion of phyla, I think it's reasonable to expect that process to continue over the next 500 million years.....what stopped it?Are you proposing that evolution is limited to prescribed designs?Edited by randman, : No reason given.

Just trying to make sense of your posts. It's like you think there are missing phyla.

randman, As I have already pointed out, vertEbrata is not a phylum, vertebrates belong to phylum chordata.This phylum has organisms as diverse as:Seasquirts: Tunicates: Elephants: Whales: Teleost Fishes: Mammals: Amphibians: I could go on. The point is, that in this phyla, only tunicates & seasquirts are found in the Cambrian, the rest are subclades of phylum chordata that evolved later. You seem to want to present the Cambrian phyla as unchanging & unevolving, having somehow lost the capacity to do so. I think a seasquirt to a flying frog under any other circumstances would warrant separate phyla having evolved, wouldn't you?Why isn't it? For the reasons I have explained in message 41. Which you didn't respond to, I might add.MarkEdited by mark24, : Remove advertising from image

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