nested heirarchies as evidence against darwinian evolution

I believe the question is why did invertebrates not show much change anymore after one population gave rise to vertebrates.?Why couldn't another population give rise to something else and eventually become drastically different? The only change since this 'event' were very minor evolutionary changes..
Similarly, how is it that the ancestor of Man and Chimpanzee is very different from Man and not so different from the modern chimpanzee? Why could not another population of apes evolve from the chimpanzee? Why is it that the parent population has not changed much but is still around?
Why could not another population of fish give rise to another type of land animal - perhaps with different types of adaptations than amphibians?I think this is the gist of the main question? Why is the parent population still virtually unchanged, still around and not able to give rise to anything new save for that ONE time?I hope there is an explanation for this because I believe I understood evolution quite well and simply assumed that there was not an available niche for the animal to branch off again. But I don't think this is a sufficient explanation.

I believe that Randman is trying to say the following:He claims (and may or may not be right) that say there is a group A of animals composing of hundreds of thousands of different species. It is claimed by evos that one population diverged and became different enough to be part of a new group B. However all the remaining species in A remained almost exactly the same with very little change for hundreds of MILLIONS of years. Why is this the case? Why can't another population of this very large group A diverge? I think what he is suggesting is that no population EVER diverged from Group A to form group B, and that the fossil record simply shows that Group B appeared suddenly in the fossil record.
Now this can easily be disproved if one can show examples of different groups diverging from the parent group which has lived on till now. The lingering doubt exists because the fossil record does not indicate this i.e species suddenly appear.
Personally, I think that random mutation alone may not be able to account for all new traits introduced into a population - there seems to be an unknown process involved here.

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What happened was that A branched into B and C. A ceased to exist. Thus A will never diverge again, since extinct populations don't reproduce by definition.

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NO! Group A continued to reproduce and remained essentially the SAME until present time. Some species did go extinct but the ones that remained other than a few superficial changes remain the same.
I find it strange that such well observed fact is being disputed.Take invertebrates for instance, how much 'evolutionary change' has occurred in each species - they have remained essentially the same for eons. Many species have gone extinct but the remaining haven't changed much.

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Show me this ancestral population of animals then. Show me this unevolved population that is the same species of beings as the proposed common ancestor of all living animals.

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Actually you should show me ..)But just to clarify - What I meant by group A consists of thousands maybe millions of different species. One population of species X supposedly diverged evolved eventually forming species y,z etc and diverging out of this group. Now all we see are the results: this group B consisting of many different species whose common ancestor is species X from group A. I agree species X no longer exists. However group A still exists virtually unchanged = this is my point.

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They might look similar to you but they are not the ancestral population. They have evolved considerably since then.

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Sure, they reproduced many times but 'evolved' ? - No.Here is one species virtually unchanged.http://www.wildcalifornia.org/pressreleases/number-28And to counter your point all the species that you claim to have evolved from ancient populations have appeared suddenly in the fossil record. The rest either are extinct or are UNCHANGED.Actually I don't mind if you show me a two or 3 species that HAVE changed over time in a major way. (macro evolution)I cannot name all the different species on this planet but just for starters - how about the Crocodile virtually unchanged before it suddenly appeared. The only changes that have been observed are variations in color size etcWhat bothers me about evolution is that the species that have supposedly changed seem to have appeared in a very short time. At the very least, the rate of evolution varies from very fast to very slow.

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Chordates that were represented in the Cambrian by tunicates & seasquirty soft bodied organisms, that in the modern day now include, elephants, humans, eels & sharks. Please explain to those silly muddle headed biologists how this represents them not having changed much?

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They suddenly appeared in the fossil record. You assume they have evolved but I would like to see some evidence of this proposed evolution.

I think it would be a good idea if someone in favor of evolution can post or give a link to some material that summarizes in about a page or few pages the basic groupings that have evolved from the beginning to the present.
So we start with a one celled organism -- at some time this diverged to something etc.
I am specially interested in the Cambrian era during which all phyla appeared (is this true or not?) .

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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