Friday, March 30, 2007

That Mammal Study


There have been a lot of reactions and comments to this study. There have been a lot of criticisms of said study. Read a lot of the informed comments at Pharyngula. PZ Meyers then went and recommended reading Sandwalk's commentary.

I then cried out in a bit of nastiness upon reading it that was designed explicitly for PZ Meyers: Gawd's Own Butthole! Why?

Read this:

Furthermore, the data clearly shows no connection between the mass extinction event at the K/T boundary (65 Myr ago) and subsequent radiations of mammalian groups. This effectively rules puts an end to the long held belief that mammals diversified after the devastation in order to fill up the niches left by dinosaurs. This is not the first paper to refute that belief but it may be the final nail in the coffin.

This summary serves as a warning to those who continue to associate evolution with environmental change. At this level of analysis there does not seem to be a connection between rates of speciation and climate change. This is most obvious with respect to the asteroid impact of 65 My ago. While it led to mass extinction, it did not lead to increases in the rate of evolution of the survivors. The branching pattern of cladogenesis in the figure is hardly affected by the cataclysm.

(emphasis added)

1. This study was about modern mammal orders. This excludes all those that got mopped between the KT and now. There are numerous orders that are no longer with us. It's very well known by the paleo types that study mass extinctions that the critters that arise immediately after a ME event are often not those that carry on later. As I stated up on James Nicoll's LJ, The Paleogene and Triassic had rather different ecologies than the subsequent rest of their respective eras.

2. The rise of the modern orders happens to coincide with, oh, say the damned End Eocene Extinctions? Wait. Is that an environmental change? Gasp, yes, it was! The origination of the different mammal lineages happens to track, at first glance, with the fact that Laurasia and Gondwanaland were tearing themselves apart at the time. And if you look at the paleogeography (here and here), it gets even more apparent.

I am going to stop there. I am already irritated and I am likely if I add to much more to pop something off that will reflect badly on me.

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