>>10572548evolvability is determined by genomic and environmental factors, the tropics and their evolutionary dynamics are largely isolated during glacial periods, the temperature difference is negligible, additionally if a glacial period, one only a few million years in length (<2mya) is enough time to cause most mammal species to be “cold adapted”, which it isn’t, then the warmer interglacial periods should also have marked effects on the evolution of these organisms. Every part of the argument is incoherent, and they’re also wrong, biodiversity is negatively correlated with cold temperatures, so most species evolve in temperate or warm climates, they are adapted to mild or higher temperatures, not to cold climates. The thread that has been lost is in the very notion that if one were to significantly accelerate a cooling period that is supposed to take 20-50k years to occur most life would just adapt. Strong changes in temp have serious disruptive effects on ecosystems and tend to coincide with mass die-offs as selection pressures change. I think he was referring to megafauna when he said this which is somewhat valid as they were the primary source of protein and fat in the diets of eurasian hunter gatherers but a large number of megafauna subsisted in temperate or even in some cases tropical climates, they were not all cold adapted and there is no telling how modern megafauna, most of which is found in the tropical, subtropical and temperate climates of the earth, would respond to rapid glaciation and temp drops. They are also just wrong about birds, insects, amphibians and reptiles, almost none of which are found at high densities north of the tropics. Europe has some of the lowest biodiversity on Earth besides the polar regions for instance.
