Climate change may have driven evolution, scientists believe - Telegraph
Rapid climate change in Africa two million years ago may have driven human evolution, researchers believe.
The early landscape shifted between woodland to grassland half a dozen times over 200,000 years, meaning man had to adapt to survive.
Experts from Penn State university say that this may have set the tone for the rapid evolution which then took place.
Writing in the Proceedings of the National Academy of Sciences, Clayton Magill said: "The landscape early humans were inhabiting transitioned rapidly back and forth between a closed woodland and an open grassland about five to six times during a period of 200,000 years.
"These changes happened very abruptly, with each transition occurring over hundreds to just a few thousand years."
Professor Katherine Freeman said: "There is a view this time in Africa was the 'Great Drying,' when the environment slowly dried out over 3 million years.
"But our data show that it was not a grand progression towards dry; the environment was highly variable."
This rapid change could have triggered development of the brain, said Magill.
He said: "Early humans went from having trees available to having only grasses available in just 10 to 100 generations, and their diets would have had to change in response.