nested heirarchies as evidence against darwinian evolution

No, it's not the same, as I have shown several times now. For example, we still have non-vertebrates around and they were around 500 million years ago. Why have they not evolved new major forms as they did before?At a minimum, why have no new lines of vertebrates evolved, or really whole new body-plans.....maybe with a better design?Whatever mechanism created the phyla appeared to stop?

Simple. Why was it ever the case? Think about it.And yes, you can't escape this. The process has stopped. No new phyla has emerged in 500 million years. There is no credible reason for new phyla to emerge and then quit emerging. You cannot handwaive this away and say, well, there just wasn't a competitive advantage because things were still evolving, right? There were extinctions, new forms evolving, etc,....(according to evos) but for some reason they were evolving all within these animal phyla. They were constrained within certain limitations, if you buy they evolved at all.Why was that?You cannot say, well, it's because, you know, like having a great grandfather, a grandfather, father, etc,....and the reason that doesn't work is, so what? That was true for the organisms that presumably evolved into the major phyla, right?There was a line just like you guys posted, but somehow we saw the appearance of all the animal phyla nonetheless. There was a significant broad change fanning out, and then it stopped.Isn't this what Grasse was saying as well as many other scientists, that evolution seems to be winding down?

Not that I can see. The questions you repeat yet again have been answered and not rebutted.--Percy

I understand the term and modulous' point perfectly well, but I think he is glossing over this. You can talk about different terms and descriptions of the same thing, but there is a reason Grasse and others suggested that evolution appears to be winding down and lacking whatever mechanism produced the phyla or if you want to back up a bit, produced vertebrates for that matter.If invertebrates evolved into vertebrates, for example, over 500 million years ago, why hasn't that happened again and again?

So we have multiple new lines of vertebrates that have evolved/arisen from invertebrates over the past 500 million years?Could you cite something showing that?Edit to add a comment that may help. In your analogy about your grandfather and your father, let's imagine that they never die and keep having kids. They keep on living as invertebrates have.You should then continually have new brothers and sisters and new cousins, etc,...... that "evolve" outside the line you are in.There should be multiple instances of invertebrates evolving vertebrates and the process should be repeated often over the past 500 million years.Edited by randman, : No reason given.Edited by randman, : No reason given.

You've argued that because evolution predicts that such lines should exist, the fact that they don't is evidence against evolution. The replies have explained why you're looking at this the wrong way. I think you need to engage rather than ignore these explanations. New distant cousins from great great grandfather lines? Sure! New brothers and sisters? Of course not. I think there must still be something about this that you're not getting.--Percy

Because primitive life has more opportunities. Think about the most worst kind of life. The kind of life that only just gets by - it is hanging on a thread of existence and its continuing survival is a miracle. There are only two ways it's offspring can vary. They will either be dead or they will be better. The better ones, by definition will be the ones that reproduce yet again.So - when life was very primitive there was a lot of scope for change. Now animal is on the whole highly specialized. To evolve away from this specialization would usually entail a reduction in fitness. To evolve away from the primitive condition does not necessarily imply a reduction in fitness. Correct. And evolution doesn't suggest they should. New ancestral clades don't just pop up ex nihilo. Any new evolutionary paths that are taken today will face stiff opposition from highly advanced specialists in the niche. If they managed to dig themselves in and get established, they would still not be classified as a new phylum. In 500my time, maybe what we call 'families' will be as broad as what we call classes or phyla today. Maybe not. There's no reason it has to go either way. Because you inherit things from your ancestors. That is an inherent constraint in the evolutionary model.In simple terms, at first there was just life. Then there were a variety of life forms which for our convenience we have called various kingdoms. Those kingdoms split up and those subgroups we have called phyla. Each one of those phyla were subgroups of a kingdom. The phyla split up, and each branch would forever be part of the phyla its ancestors were part of. Either those things which were still part of a kingdom with no phyla died off, or they later became part of their own phyla. Once this occurred there could never be 'new' phyla. Maybe we might get a bit confused in our classifications and what we have previously called a 'phylum' are actually subgroups of another group after kingdom. So we create a classification between phyla and kingdoms.No matter what bizarre life forms evolve now, there will never be a new phylum - unless the life form is part of a previously undiscovered phylum. It is unlikely there are any life forms around now that are members of a kingdom but are not members of a phylum. Every one of their descendants will be thus part of that phylum. It didn't stop, it just got more and more specialized so we invent new names for the subgroups of the earlier broad groups. We could say the same thing for the kingdoms or for the classes. That's what a nested hierarchy is. Hypothetically there could be a period when all extant life has reached its equilibrium all at the same time. Maybe we are in a period of total or broad equilibrium now. What difference would that make to nested hierarchies as evidence against evolution? However, Grasse is hardly an authority that is likely to sway my opinion on this alone: If you want to convince me that evolution is winding down, you'll need to do better than quote a single zoologist who was born in the 19th century and was anti-Darwinian whose replacement ideas for Darwinian evolution have not really gone anywhere.

Let's be specific. Non-verterbrates evolved into vertebrates over 500 million years ago, according to evos, right?Non-vertebrates are still around, right?They've been around all this time, right?Darwinian evolution has been around all this time, correct?There is really no reason then for vertibrates not to evolve again and again, and newer different body forms.Think of like this. Your great grandfather has sex and has children and they get married and do the same, but this old guy never dies. He's the same. The sex is the same, and he keeps spitting out children.....except in your theory, even though everything is presumably the same, he keeps having sex, but stops producing children.Does that make sense?I am repeating myself again and again, and you aren't addressing the point. I am not missing your or anyone's argument here. It's quite simple. The old lines are still around in one form or another. Why have they quit producing?

No. Non-vertebrates remained non-vertebrates around 500 million years ago, as they do now. Only one species of them would have become the fathers of all vertebrates at that time, and there's no reason that another should, any more than there's a reason that the chimps or gorillas or any other apes or primates should become us.Fish don't automatically become amphibians, only one lineage did, and amphibians remain amphibians, except for one lot that became reptiles, and reptiles remain reptiles except for one lot that became mammals, etc.There is no reason why any of these specific processes should repeat themselves.

I'm trying to keep my involvement in this thread light. Several people have explained to you why this isn't true, and I think you need to engage those people in discussion. It's comprehensible but not analogous to evolutionary history. I'm going to slip into moderator mode.Randman, you're going to have to figure your own way out of the maze you're creating for yourself. The moderators will not be continually intervening in threads you participate in. "Why have they quit producing?" is a valid question, but it's been answered several times. Engage in discussion those who have been offering you answers (I only tried to produce an analogy consistent with those answers, I wasn't trying to provide my own answer) and stop repeating the question.Google provides a spellchecker for IE and Firefox, and Firefox has a built in spellchecker.--Percy

Putting this into a general reply. The argument that competition keeps out new lines of evolution is why you guys are saying non-vertebrates, for example, did not evolve into newer lines of vertebrates or other things.right?Modulous, you also argue that essentially new phyla have evolved and we call them sub-phyla, classes, etc,....I assume you are saying just as much genetic and morpholical diversity has evolved since the appearance of the major phyla, right?Do you see a contradiction here?On the one hand, you are arguing the situation stabilized so that more evolution was shut out, and on the other hand, maintaining that there was no difference, that evolution continued unabated but we label things differently.So which is it?Moreover, and I asked this before and no one supplied anything, where are the peer-reviewed studies backing up your hypotheses?Anyone can imagine a hypothesis, but how is it established? You say organisms that evolved animal phyla were shut out, and that newer forms could not evolve? Well, prove that hypothesis.Is it reasonable? Think about the time mammals appeared, for example. There were lots of dinosaurs around, no? But there was still room.Plus, there have been major extinction events over geologic time. So there is no reason to think over 500 million years a process so powerful as to produce the Cambrian explosion would not occur again and again.But it doesn't. Evos say vertebrates arose only once, right?That's a fact, right?So show me the peer-reviewed studies to explain and justify the hypothesis that it's reasonable for vertebrates to evolve only once, please.

The argument appears to be that because vertebrates were already established, no new vertebrates could evolve. I think the fact that new vertebrates in the old line are said to evolve amply disproves that, but let's move on.Why would there not be new body-plans evolving forming new phyla from the same types of organisms? Did they spend their evo energy so to speak and so only the old lines can evolve?Moreover, doesn't this suggest a limitation of what sorts of body-plans could evolve? If non-vertebrates could not evolve new strains of vertebrates and nothing new to challenge the verterbrate and other existing animal phyla, that suggests that there is a prediposition to evolve in a certain direction, right?Edited by randman, : No reason given.

I'm suggesting that it may require a drop in fitness for a specialist to change its general body plan significantly enough to satisfy what you are after. One possibility that it might require a drop in fitness is because of the fact that all of the specialists they will be competing with are likely to outcompete them. I'm arguing that new evolution continued after the Cambrian, but not that new phyla have evolved. The subgroups of the phyla are broadly called Class, Order, Family, Genus and Species - though further subcategories are used where necessary. Not at all. I am simply saying that there is no reason to expect large fundamental changes such as a modern invertebrate developing a backbone. Plenty of evolution has happened since chordata came around and the window of opportunity to evolve these structures may simply have passed. That does not mean I am implying that other windows might not be opened. I have made no such claim. I simply said that the descendants of the first members of any given phylum will all be members of that phylum. I went on to say that there is no necessity in biology for backbones to evolve in a population of non-backboned entities. This may be because the opportunity has never arisen in any members of this lineage or it may be because it has but that lineage went unfortunately extinct by bad luck - or maybe it went extinct because it could not compete with its backboneless competition. These are just possible reasons as to why we have not seen backbones appear in other entities.The easiest way of putting is that things (including other life forms and extant genes) were different then. When we have different conditions, we expect different outcomes. If you can tell me about an extinction event that put the earth into a condition much like that during the Cambrian period, we'll talk about it. If it wasn't much like the Cambrian period, I don't see any reason to assume that these things have to have happened. The chordata phlyum did, but there is also the Hemichordata phylum, whose members have a notochord that is proposed to be independently evolved to the more famous chordata, although some propose that they both inherited their notochords from an earlier common ancestor. I'd still like to know what is unreasonable about the proposition that some events can only happen under certain conditions, and in an environment of constantly changing conditions it is possible that that some events may never happen, or only happen once or twice.Sometimes rand, you can't get there from here. Modern genomes may simply not be able to change in the ways you are thinking of within the realms of reasonable probability - and even those that can, it might require several hundred generations of increasingly less fit organisms, which would also render it improbable.I don't know why this has happened (I can only think of a few reasons why it might be the case - and thus argue why it doesn't need to be the case), but you think you know that it should have happened if modern evolutionary theory is true. If you are right, then I will concede the point.You'll need to show how evolutionary theory, and the evidence from genetics and zoology/paleontology demands that invertebrates should evolve vertebrae more than a small number of times (or once). To do that, you'll need to draw upon the literature to weave a theory that explains why this should be the case if evolution were true. I doubt you'll do that so we'll just have to rely on argumentation.Thus: You claim it should have happened. I claim that it might have happened, but there are any number of factors that could prevent it. Where would you like to go from here?Finally, this is still irrelevant to nested hierarchies. Perhaps you should change the OP, or at least the title, to reflect the evolution of the phyla or whatever it is you wish to actually discuss? As I previously explained, if we discovered a family of nematodes with backbones - they wouldn't get a new phylum. They'd still be in the nematode phylum.

Not really my argument, although it would make sense that if there's an ecological niche available for a vertebrate type animal, it would be more quickly filled by something diverging from another vertebrate than the far more complex evolution required to produce a new type of vertebrate.The point is, rather, that the evolutionary change from an invertebrate to a vertebrate is a complex and specific process, and there's no reason that it should happen more than once.Think of it as like the one reptile that evolved into a mammal. It's a very specific process, and there's no reason for it to happen again.When you do get convergent evolution, it's always far less complex, and it's superficial. A killer whale has evolved a shark-like body because it's a good practical shape, but it's extremely unlikely to become a real fish! No reason to suppose so. The planet, with a slightly different history, could easily have never evolved vertebrates. Remember, if the K-T extinction event hadn't happened, we wouldn't be here.And the point isn't that another vertebrate type thing couldn't possibly evolve from a non-vertebrate, rather that there's no reason why it should happen. For some strange reason, you seem to think that evolution not replicating itself is an argument against it happening, or for creation, or something.How often do you expect mammals to evolve from reptiles?

Why? With more animals, there are more possible niches. Why? Because people say so. But look at this way, even if you discount new vertebrates based on this reasoning, why wouldn't something else pop up?Do we really think all the possible phyla evolved and shut the door on any new forms? If that's the case, then there appears to be a predetermined fixation of what possible forms could evolve. Evos say that all the time like a mantra, but it's not true. Is the mammalian ear, for example, "superficial"? Why would it evolve independently 3 times?In general, we see a repetition of specific traits that are not superficial and include inward organs, teeth, hair, and pretty much the whole gambit of traits, whether outward or inward. Is a canine marsupial only superficially resembling a canine placental?No, they are very similar. There are differences, sure, but the similarities are not confined to "superficial" traits such as a shark and a whale body.