"Archaeopteryx; bird or reptile, or both?"

I brought this up on the PNT, but thought it might be an appropiate comment here as well. I understand that by transitional, you do not mean that it is the ancestot of any later species, but simply shows the evolution of forms that later species had, but that the idea is these forms could have stemmed from a different species.However, presumably there is the assumption of a common ancestor prior to the transitional species whose evolutionary line died out, the old bush illustration rather then the tree, right?But cannot similar traits arise also from convergent evolution, and not a shared common ancestor passing a common trait down? How can you tell if the commonalities of so-called transitional species are not due to just species out there being subject to commonalities such as similar environment, physical laws, etc,...as occurs with convergent evolution?Moreover, since similarities can evolve independently of a mutal common ancestor passing those similar traits down, does that not undercut the whole assumption used in examining fossils, namely that if they are similar, they got their similar traits from a common ancestor?This message has been edited by randman, 06-04-2005 03:48 AM

Let's keep the loaded semantics out of the picture, shall we?Homologies are by definition shared traits from common descent. So you cannot theorize about homologies not being shared traits.You can discuss similarities that are considered to stem from common ancestry.Not trying to be picky, but think the whole discussion can proceed better if we keep such terms out of the discussion.Otherwise, we really have to decide if similarities should be called homologies, homoplasies, or neither (which is of course what we are trying to do here, but just to make a point). That seems logical except that convergent DNA sequencing suggests otherwise. But it's an interesting point. If environmental pressures must be applied to create convergency, and we find examples of convergency that do not seem driven by environmental pressure, would that be evidence of a hidden environmental pressure such as an intelligent agent? Good point except we need specifics, and I have a question, are not the homologies advantageous for both groups of species? Assuming they are, that they are due to natural selection, why could they not be an example of convergent evolution?Can a trait not be selected for, even when the 2 species have different lifestyles? You are assuming that the trait can only evolve independently from one set of circumstances, and that's just an assumption.Plus, what if it did not evolve from convergency from outside selective pressures, but from convergent DNA, or ID (an intelligent agent), or just by golly, the same trait worked for both and independently evolved.Common descent is not the only answer here.

I just posted a long reply, but did not realize this was on this thread still.If you want to respond more, why don't you quote my post with your response following and put it over on the new thread so we keep each thread topic clear?Or not.Either way is good.