Cleaning off my desk this evening, I found an interesting paper I’d printed and set aside to read weeks ago by Alison Smith in Holocene about the relationship between climate change and human evolution. Smith uses data from the human genome project on the timing of major bits of human evolution to argue that pressures from abrupt climate change during the last 10,000 years can be linked in time to major steps in human evolution:
For example, 5000 to 6000 years ago, changes occurred in the human genome, including among others
the development in some populations of lactose tolerance, the development of malarial resistance and an increase in brain size. These changes occurred in regionally distributed populations responding to some strong positive selection pressure. I suggest that the source of the selection pressure may have been the abrupt climate change documented as occurring at the close of the mid-Holocene hypsithermal climatic optimum), 5000–6000 years ago.