nested heirarchies as evidence against darwinian evolution

you think that because of common descent, common descent is impossible. yeah? witty argument, i'll admit, but wrong in very many ways.evolution happens on the species level, not the phylum level. the phyla that are represented in the cambrian explosion were made by speciation, and we arbitrarily rank them very low because of the long genetic history that follows them, and the short genetic history that preceeded them. asking for new phyla today is about much sense as asking for a new great-great-great-great-grand-uncle. the person that would have had to have been his father has been dead for quite some time. all we have left are the descendents that actually exist. frankly, at the precambrian level, it doesn't make a whole lot or difference. you take one arrangement of protozoa, you get sponges. you take another, you get algae. you're essentially asking for new arrangements of protozoa -- like it or not, possible examples include plants and fungi.

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and there's one flaw in your argument as well. populations go extinct. there's another flaw in your argument. similar? descendents. another flaw in your argument. you're not going to get any new tribes of israel that are on the same ranking as the 12 because israel died, and left his 12 sons. those sons had sons -- and all of his descendents belonged to one of those 12 tribes. your point is nonsense. it's as preposterous as my statement above about tribes of israel. there's nothing there to understand. perhaps if you'd go and actually study invertebrate paleontology, you'd learn exactly how much nonsense it is.

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First off, you claimed that only 8 did. That's a big difference betwen saying only 8 had fossils, which isn't true by the way, and that clearly others emerged later, which is what you wrote here: Apparently that was an incorrect statement, right?Secondly, since many phyla have never left fossils at all, I would think you would know that most evo scientists still believe they emerged in the Cambrian era or prior, exactly as I cited. You rudely suggested I was wrong when in reality, I was simply and accurately conveying accepted scientific opinion, an opinion which you apparently accept as well, despite your claims otherwise earlier.Third, let's look at your comment: You DID NOT say we don't know if the 33 emerged then due a lack of fossil evidence, which would also be incorrect. You stated "did not occur." You made a statement of fact without any evidence to support it, and apparently actually knowing the opposite was true, that there is evidence, as you apparently believe, that most animal phyla emerged during or prior to the Cambrian.So let me ask: why did you make an erroneous or seemingly false factual statement to counter my post?Do you now admit that your claim below is a false statement? Note by "false" I mean incorrect, though the fact you said you believed otherwise is puzzling to say the least, but be that as it may, perhaps you just mispoke and you meant to convey, "yes, you are right that it is accepted opinion most animal phyla appeared during the Cambrian era, but we do not have all the fossils to prove it".Is that what you were trying to say?For the papers you cite, could you provide a link to them so we can see if they genuinely say what you say they do?Edited by randman, : No reason given.Edited by randman, : No reason given.Edited by randman, : No reason given.

indeed. evolution happens on the species level. it's not a theory that things randomly POOF into existence. that's creationism. common descent means that things have a common ancestor, and asking for that ancestor to have new offspring makes little sense. yes, some of the offspring have remained remarkably similar over the years, but they are also a pre-existing phylum in our rather arbitrary grouping.as i've pointed out repeatedly, we're really talking about a group or two of sponges, a group of corals, bryozoa, and about 30 kinds of worms. and those worms, imo, are a good deal more advanced than the others. i think you'll even find that our "ancestral worm" was descended from neotenic larvae of something like a tunicate, which is something like an advanced sponge.

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indeed. evolution happens on the species level. it's not a theory that things randomly POOF into existence. that's creationism.

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Yes, but it does seem this way. It looks a lot like all or almost all the phyla appeared in one era and subsequently at other times (assuming that the the dating is correct ) other types also appear suddenly.Also, if the ancestor population still exists then there should be no reason why another population breaks off from it afterwards. It strikes me as odd that a lot of 'evolution' has happened in bursts and then none at all.I am surprised that everyone gets so upset - clearly there must be something right about what Randman is saying

So you believed all along, or did you change your view during this thread "that most phyla originated before or near the beginning of the Cambrian"?If you believed all along "most had", why did you insist only 8 had?The most charitable explanation I can think of is that you changed your views as a result of this thread, and the 2nd most charitable I can think is that you simply had forgotten what the evidence and accepted opinion is.Try to look at it from my perspective. You erroneously and rudely suggested I was wrong and that only 8 out of 33 phyla had emerged, and now you admit you believed "most" had emerged by then. Why then did you derail the discussion into such an erroneous claim of a minority of phyla having emerged if you believed otherwise?Why did we spend all this time debating this point if you essentially agreed with me all along?Moreover, in case you do disagree, please state the phyla, and the evidence for it, for phyla emerging later than 500 million years ago or close to it? So? Isn't the point of this thread to examine these facts assuming evo dating methods? Maybe you didn't read the OP carefully? Here is what I stated: Edited by randman, : No reason given.

this is just not the case. records from the pre-cambrian are poor, but not nonexistant. it looks like a bunch of phyla appearing quite suddenly because of the overwhelming presence of calcium carbonate, which alot of the early phyla put to use (in different ways), making them much more likely to fossilize. in any case, the cambrian explosion happened much more slowly than creationists would like to think, and many of the things we call phyla today had intermediate common ancestors. for instance, chordata (that's us!) is much more closely related to echinodermata (starfish) than it is to porifera (sponges) which retain a lot of the ancestral choanoflagellate colony characteristics -- even though the earliest form of chordate, the tunicates, look a lot like sponges in their adult forms. in other words, "phylum" is completely arbitrary, and there are divisions of the tree that group phyla as well. the ancestor population does not still exist. like it or not, animals do not live 500 million years. all we have left are the more primitive animals that most closely resemble the common ancester of all animals, the sponges. they are not the original populat, but descendents. any division that happens there would necessarily group them in the phylum porifera, which we have arbitrarily assigned to that hereditary clade. evolution doesn't die down to "none at all" but i have no comment on the rates, re: punc-eq. yes, just like the joke that gets groans must be funny.

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skepticfaith, No, most phyla appeared outside the cambrian. All of the plant phyla, among others.If the dating is incorrect then you are utterly & completely robbed of any point whatsoever.Mark

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There are 10 kinds of people in this world; those that understand binary, & those that don't

I'm closing this thread for 24 hours. If the tone of the debate doesn't improve when it reopens I'll start suspending individuals for 24 hours.

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--	Percy
	EvC Forum Director

Please keep discussion focused on the topic. Seek the best in those you disagree with and you will find it.

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--	Percy
	EvC Forum Director

I hope I can start this back up with a more civil tone. I'd like to start more or less at the beginning again, with one of randman's 3 original points. Specifically, the first one:

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1. Essentially except one possibility around 470 million years ago, all animal phyla had appeared or evolved around the time of the Cambrian explosion 500 million years ago. Since that time, no new animal phyla have appeared or evolved IN 500 MILLION YEARS. Apparently whatever processes or creative events that evolved, created or animated the appearance of the animal phyla has not been in process for the past 500 million years. If it had, we would see new phyla emerging and we do not. Certainly, there have been quite a few extinctions during that time to open ecological niches up.

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This is really a semantic argument stemming from the common Western-Hemisphere cultural obsession with defining and categorizing things. The word "phylum" doesn't mean anything in particular: it was coined before evolutionary theories had really taken hold in science, and so is erroneously applied to evolution. It is most often defined in terms of its position in the nested hierarchy of descent, which requires it to be a very old lineage.All animals found in the Cambrian deposits were fairly simple types. The one chordate found, Pikaia, only has a notocord, and apparently no real skeleton. In fact, Pikaia looks more like the other soft-bodied, wormlike organisms of its time than it does like any of its purported modern descendants (the modern chordates, including us). So, the first member of what we call a "phylum" is not going to be a completely distinct organism, but will be derived from already existing stock, and its descendants will only later become sufficiently distinct to merit the title of "phylum." That's where the idea of nested hierarchies comes into play in support of evolution.In summary, if you define a phylum by its level of distinction from other groups, of necessity you require it to be something that had its origin a very long time ago. This is because, according to evolutionary theory, it takes a long time for significant changes to occur. So, the ancestors of tomorrow's new phyla are evolving today, in the form of new species, new genera, and new families. Each species holds the potential of diversifying into a genus, and each genus, of diversifying into a family, and so on.Edited by bluejay, : Grammar.

In other words the depth of a taxonomic division is related to the age of the common ancestor where the divide occurs.In fact you could build an arbitrary tree based on common ancestor relationships using just certain specified ages (1 every million years?) and the species alive at those times to define the names for those levels of development.When you are done, compare it to a standard taxonomic tree.Welcome to the fray bluejay.

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Thanks, RAZD. I think that was kind of the point of the Linnaean system: to define exactly how closely related animals were to each other. But, Linnaeus was a creationist, and believed in the immutability of species. So, "relatedness," in his opinion, meant "similarity."Today, "relatedness" is generally held to mean "time since the divergence from the last common ancestor." This has obviously required adjustments to Linnaeus's system, however.On to randman's second point: The part that I want to draw your attention to is the part where it reads "almost everyone had the point of a 'common ancestor'... undiscovered yet." If even only one or two of these 'common ancestor points' (as they're called here) had been discovered, it would completely and utterly destroy the creationist model.Either that, or creationists would have to accept that the biblical "kind" is much more expansive than they commonly believe. If birds are considered part of the "reptile kind," and stegocephalians are considered part of the "fish kind," the "kind" concept may have to be drawn back to "vertebrate kind," or even, "animal kind," which would essentially admit that evolution was true, with the caveat that animals can't reproduce with mushrooms and plants can't reproduce with slime molds. That's not a problem for evolutionary theory, though.This is largely a semantic argument, though, and may very well be invalid. I suggest somebody produce this chart: I want to see it myself.Edited by Bluejay, : Addition

This is similar to the denial of transitional fossils where - for the avid creationist - every time you find a transitional fossil you create an additional gap. The difference is that here we can use genetic data to show the nested hierarchy and then compare that to the fossil evidence to see how they fit together.One can use the hominid tree from the Smithsonian Institute: Early Human PhylogenyOr one compiled by Bruce MacEvoy: Human Evolution

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Human evolution is a puzzle made up of thousands of fossil pieces. The Chart of Human Evolution (below) shows the major pieces of that puzzle arranged in a likely solution, which is open to clarification as new fossil or DNA evidence is reviewed in the scientific literature.

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Getting back to the "nested hierarchies" of the openning post we see this from Bruce MacEvoy:

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According to The Tree of Life by Guillaume Lecointre and Hervé Le Guyader (Harvard University Press: 2006), the similarly named and easily confused categories of humans and near human apes, in order of increasing inclusiveness, are:

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” Hominini - modern humans and all previous human or australopithicine ancestors

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” Homininae - humans and chimpanzees (Panini), our closest living biological kin (so close that some scientists have suggested their genus name should be changed from Pan to Homo).

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” Hominidae - humans, chimpanzees and gorillas (Gorillinae)

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” Hominoidae - humans, chimpanzees, gorillas and orangutans (Pongidae)

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” Hominoidea - humans, chimpanzees, gorillas, orangutans and gibbons (Hylobatoidae).

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http://www.handprint.com/LS/ANC/apes.gif

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This is the nested hierarchy that is based on genetic information from existing species.Enjoy.

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Hi randman.
After reading your original post and subsequent pages, it seems to this observer there are still some things you maybe are not quite catching. Maybe I can help explain this too you with some simple, imaginative, cartoonish, yet illustrative examples.You'll have to forgive the poor art skills, as I am doing this on my laptop without a mouse! Also please bare with me a moment while we set this up then I will get to your questions.Lets pretend for a moment, we have some make believe planet (name it whatever you like). And on this planet lives a species (an ancestor to all life on the planet) we will call Bobs. The happy little black dots. Now there is one population of Bobs, but after some amount of time something happens that causes the population to be split in half and these two new populations are reproductively isolated from each other. After some amount of time, the changes to each population (through differing selection pressures) eventually becomes so great that we call them different species; Jims and Jons. After sometime both of these new species produce more (from left to right; Sams, Sallys, Steves, Sarahs, and Stephs) And more(Petes, Pauls, Zachs, Rons, Robs, Rays) Now something I forgot to include is some kind of time scale, so the farther down the page a dot or node is the later in this planets geological time it occurs.This branching we see is an emergent property of the relationships of 'dots' in the system. We can assign arbitrary taxonomic names to nonarbitrary groupings within the tree (nested sets if you will).Take for instance the first split from the Bobs. We have the Jims and Jons. We can call them Kingdoms, Domains, Super Cool Color Groups, whatever you want, the name is not important. What is important is that each group and all of its descendent's share some common features.From each of these groups (Jims and Jons) arise even more groups. Again we can assign whatever name we wish (phyla for instance), the name is not important, but again the important part is that all the ancestors of the Sams, Sallys, Steves, Sarahs, and Stephs have some features common to the groups, our nested sets again.So you ask why don't we see phyla being created still? In our example what we call phyla arose at the time of the Sams, Sallys, Steves, Sarahs, and Stephs. For more groups to arise, we would need the Jims and Jons to have another divergence. The problem is if our Jims and Jons are extinct how can that happen? Anything that arises from the Sams, Sallys, Steves, Sarahs, and Stephs will belong to one of those phyla, not a new phyla, no matter the morphological extremity. This is because, while their descendants may gain new features, these features will not be shared amongst the higher group. In other words, there is no way to travel to the past and create new forms at the level of the Sams, Sallys, Steves, Sarahs, and Stephs.Something else you appear to be hung up on is similarity in ancestry. It can get pretty confusing to think about. But your vertebrate/invertebrate example shows that your not quite grasping it yet. Your question is why do not new vertebrates arise from invertebrates?To answer the question, you need to first relieve yourself of the very generalized terms. Lets change your question around a little bit so that it makes more sense. Lets look at the Superphylum Deuterostome. And we can rephrase your question why can't chordates or animals with notochords arise from hemichordates (animals with primitive notochords).After looking over the example above, the answer should come to you, but just in case lets go over it. If today, we found a hemichordate that had evolved a fully functional notochord, would that be a new phyla? The answer is no. Because this newly evolved species, is an ancestor too the original hemichordate. In other words, because it is a descendant within the group hemichordata, it cannot ever 'leave' that grouping.There is no rule that says, a hemichordate evolving a notochord is impossible though, but as someone pointed out, billions of years of evolution have evolved living lineages that are very specialized in niches. Its like asking why don't dogs evolve into something squirrel like? Because squirrels already fill a particular niche, the chance that dogs could displace them would require some pretty astronomical happenings. And if a new niche opened up similar to one that squirrels already fill, then squirrels would likely be the best candidate to fill the niche.This is really interesting stuff that can really be seen in the evolution of island biota.Hope that helps, If there is any clarifications you need please or questions you have please post them and I will answer to the best of my knowledge.