Cold-adapted animals started to evolve 2.6 million years ago when the permanent ice at the poles became more prevalent. There followed a time when the continental ice sheets expanded and contracted ...

Three distinct phases of climate variability in eastern Africa coincided with shifts in hominin evolution and dispersal over the last 620,000 years, an analysis of environmental proxies from a ...

When evolution skeptics want to attack Darwin's ... exist in living species today to hypothesize the various evolutionary stages eyes may have gone through. Here's how some scientists think ...