A few days back I took on Denyse O’Leary’s "science journalism by press release" modus operandi. Now, T. Ryan Gregory has taken on the same press release while dispelling the "early branching equals primitive" fallacy that underlies O’Leary’s claims. Wander on over and have a read.
- Log in to post comments
More like this
Denyse "Buy my book" O'Leary thinks that evolutionary biologists are just like religious folk. Among the deep parallels she finds: Scientists and the religious both give booklets to children, celebrate birthdays of important figures, claim that certain things are facts, and seek official…
Why don't I blog more? In part because I'm busy reading other blogs. I finally got around to adding some of my favorite science blogs outside the scienceblogs.com empire to the blogroll over on the left side. Allow me to take a moment to introduce you to them.
The Anti-Toxo: A blog about every new…
Predictably, Denyse O’Leary is getting all excited about a paper in this week’s Nature that finds Ctenophora (comb jellies) to be the first multicellular branch off the Tree of Life, a divergence that precedes that of the relatively simpler sponges. Apparently only accessing a LiveScience article,…
Over at Uncommon Descent (no link provided due to censorship of comments), Denyse O'Leary is urging "Darwinists" to "divorce" The Descent of Man because not to do so is to support "Darwin's racism" and to thus support racism today.
I'm wondering if O'Leary actually ever read Descent and followed…
Gregory makes relevant points, but the issue is about convergence as well as complexity. One explanation for the findings is that comb jellies have independently evolved an extraordinary number of features that converge on other relatively advanced metazoans, especially jellyfish. ("Advanced" compared to placozoans and sponges.) And in which case Eumetazoa is paraphyletic. In contrast, the LCA of vertebrates and echinoderms must had a lot of traits characteristic of both groups. In fact, they have diverged rather than converged, with echinoderms evolving radial symmetry.
(Then again, possible viable morphological pathways from a primitive metazoan foundation may be quite limited, mandating a host of evolutionary convergences between comb jellies and jellyfish.)
A more likely scenario, I think, is that sponges are a "degenerate" (I know, we're not supposed to use these terms) group, perhaps one that became unicellular and re-evolved multicellularity.
Perhaps the simplest explanation is that the study's conclusion is erroneous. Who knows. More information will resolve the matter.