Devonian GeoSys-BioEvo Interaction Bun Fight

There's an interesting bun fight that has started. It has to do with whether or not there is a correlation between the rapid rise in oxygen during the Devonian and the evolution of large bodied predatory fish. Oxygen levels did, in fact, rise significantly during the Devonian. Large bodied fish that filled the predator niche also arose then.

This has been playing out in PNAS. The original paper raised the suggestion that there was a direct correlation. A researcher wrote an objection. The original researchers responded.

There is a long ongoing argument about how much the environment and the geophysical systems influence evolution. Some feel that it has overwhelming evidence in support of this. The idea that the environment is the driver of evolution is very common. Sometimes a change in climate would be a driver in evolution: the general cooling and drying at the end of the Eocene and into the Oligocene, for example. Others, as above, have suggested that the oxygen levels have been another driver. Desertification, temperature rise, etc have all been pitched as important drivers.

Others have some strong objections to this. Butterfield is a good example above. Another noted individual that you may recognize is John Hawks. He frequently objects to the idea that the environment was the driver behind human evolution.

I have to wonder. There are times when I object too when it seems like the authors are overstretching. That seems to happen alot in this realm. The grand handwave seems to be pretty common, nevermind those details. On the other hand, it seems hard to deny that the environment isn't one of the greatest, if not the greatest driver of evolution. It can and does wipe out populations of various species. It has wiped out whole ecosystems before, thereby terminating their participation in following evolutionary tales.

Sometimes the objections seem silly. Sometimes the handwavium is near violating causality. Either way, I caution that people ought to look at the details before objecting or accepting a theory.