... Borneo) where the trees are tall and quite widely spaced. http://en.wikipedia.org/wiki/Flying_and_gliding_animals In evolutionary biology, convergent evolution is the process whereby organisms not monophyletic (not closely related), independently evolve similar traits as a result of having to adapt to ecological niches or similar environments.[1] The opposite of convergent evolution is ...

In article <epvvak$1n6s$1@darwin.ediacara.org>, <drosen0000@wahoo.com> wrote: The ctenophora (i.e., the sea combs) have a bilateral symmetry but don't have any organs associated with other trioblasts. They look a little like cnidaria, which are diblastic, but I think ctenophora are triboblastic. I have seen nothing to support this. It does raise and interesting point, though...

I think that there is some conjectures that ctenophora evolved their bilateral symmetry separately from other bilaterals. However, some literature places ctenophores at the root of the bilateral tree. The ctenophora (i.e., the sea combs) have a bilateral symmetry but don't have any organs associated with other trioblasts. They look a little like cnidaria, which are diblastic, but I...

Sorry. I meant to say that the ctenophora are supposed to have evolved separately from the other bilateria, not the other ctenophora |:-) Most of what a biologist would call radial symmetry are really what a mathematician would call n-fold symmetry. A true radial animal would be absolutely and completely round. I think only some hydrozoans and sponges follow a strict radial symmetry. ...

Someone in another newsgroup said he'd heard a theory that bilateralism had evolved more than once in different phyla. Is there any basis for that? It led me to wonder, though; is Vernanimalcula supposed to be a prostome? -- Please reply to: | "Evolution is a theory that accounts pciszek at panix dot com | for variety, not superiority." Autoreply has been ...

... that the Linnean phyla are still considered monophyletic. I disagree. I found several reports showing that Platyhelminthes as traditionally defined are not monophyletic. That old phylum has been clearly broken ... is no generally-agreed-upon list of monophyletic phyla even in this one case. Also ... because they were found not to be monophyletic. Many classes and orders have been shown to...

... (1) phylum isn't a natural thing, it's an artifact of our Linnean system of nomenclature, a rather arbitrary division of life I think that the Linnean phyla are still considered monophyletic. Many classes and orders have been shown to be polyphyletic. For instance, reptiles are not a clade. Alligators are closer related to birds than to the other reptiles. Amphibians are not a ...

... division of life, and (2) several traditional phyla aren't monophyletic. Because of (1), you have to specify whose particular list of phyla ... (2), whoever you pick had better be correct in having 100%% monophyletic phyla. Offhand I don't know of *any* such list. For... are interested in, we can first judge whether each phylum is monophyletic, and if so maybe we can narrow down the "most recent"...