Joined: June 2007
So I haven't been keeping up so much recently and this is a new thread to me.
Daniel, it seems that you are arguing that there is some bound that constrains evolutionary transition. I am curious as to why you assume this must be. As I see it, you either accept that speciation occurs, or it doesn't. If you accept that it does, then the supposed macro-micro boundary dissolves instantly (indeed, it is a figment of imagination, suriving in the literature because it is a useful fiction for narrative exposition, like any other model). Why do you invoke boundaries, unless you are wedded to a phenotypical model of evolution?
So you ask about 'transitional forms'. I can point to several instances of speciation observed and/or reconstructed that do not involve transitional forms. I would start by pointing out the speciation events that involve contact between lineages of Helianthus sunflowers (see Rieseberg, Nature a few years ago) or the ecological speciation event in Rhagoletis dipterans. There is no transition. This does not deny Wesley's point about the gradual process, but it does invoke a question "At what temporal scale do we intend 'gradual' to refer to", I believe this has been addressed above. The argument against transitional forms or lineages boils down to an assertion that Zeno's Paradox is a true problem.
[Edited to add] And we know that it is not, because I just went to the store. And I returned as well.
So the saltational opinion can be resolved with the gradualist opinion by virtue of considering that the terms are not necessarily referential to an absolute scale.
You're obviously illiterate as hell. Peach, bro.-FtK
Finding something hard to believe based on the evidence, is science.-JoeG
the odds of getting some loathsome taint are low-- Gordon E Mullings Manjack Heights Montserrat
I work on molecular systems with pathway charts and such.-Giggles