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"cladistic analysis of cars will not produce a unique, consistent, well-supported tree that displays nested hierarchies. A cladistic analysis of cars (or, alternatively, a cladistic analysis of imaginary organisms with randomly assigned ch aracters) will of course result in a phylogeny, but there will be a very large number of other phylogenies, many of them with very different topologies, that are as well-supported by the same data. In contrast, a cladistic analysis of organisms or lang uag es will generally result in a well-supported nested hierarchy, without arbitrarily weighting certain characters (Ringe 1999). Cladistic analysis of a true genealogical process produces one or relatively few phylogenetic trees that are much more well-s uppo rted by the data than the other possible trees."]
Here, I feel that Theobald is being honest, but I get the feeling that he is beginning to lean toward punctuated equilibrium in that if the phylogenic data represented does not show a cle ar and concise stepwise trend, instead of question whether or not such a broad evolution took place, they make an appeal that we just might not be able to see it as clearly as one would desire.
This is incorrect. The question of "smooth" vers us "jerky" transitions is not addressed here. The point at issue is whether we can objectively construct one or a few phylogenies that have much better support from the data than th e many alternatives.
PE is not introduced to deal with the mode of transition because thqt issue is not examined at this stage.
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"quote:
There is one caveat to consider with this prediction: if rates of evolution are fast, then cladistic information can be lost over time since it would be essentially randomized. The faster the rate, the less time needed to obliterate information about the historical branching pattern of evolution. Slowly evolving characters let us see farther back into time; faster evolving characters restrict that view to more recent events. If the rate of evolution for a certain character is extremely slow, a nested hierarchy will be observed for that character only for very distantly related taxa. However, "rate of evolution" vs. "time since divergence" is relative; if common descent is tru e, then in some time frame we will always be able to observe a nested hierarchy for any given character.
Furthermore, we know empirically that different characters evolve at different rates (e.g. some genes have higher background mutation rates than othe rs). Thus, if common descent i s true, we should observe nested hierarchies over a broad range of time at various biological levels."
And here, I feel my suspicions are confirmed. While he does n ot outright mention PE, his description spells it out quite nicely. In other words, he is giving us abstract reasons for why macroevolution should be actual rather than present some actual evidence
Again you are incorrect. The point is independant of PE, and it is not produced instead of evidence, rather it is explaining what we should expect to see if evolution is true. That is the purpose of the "Prediction" subsection from which the quotes were taken - as the title indicates. The actual evidence is discussed in the "Confirmation" and "Potential Falsification" subsections following on.f
Edited by PaulK, : Minor tidying-upo
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