article_snippet: It has allowed scientists to pinpoint when the landscape in East Africa began to change as the land around the Great Rift Valley began to rise up.
article_snippet: As that part of the continent rose up, that caused the climate to become drier and drier.
article_snippet: So over millions of years, forest gave way to grasslands. '
article_snippet: Primates evolved to adapt to grasslands and dry country.
article_snippet: Dr Henry Wichura, the lead author of the latest study an a palaeontologist at the University of Postdam in Germany, said: 'Surface uplift from near sea level coincides with paleoclimatic change from a humid environment to highly variable and much drier conditions, which altered biotic communities and drove evolution in east Africa, including that of primates.'
highlights_snippet: At the time East Africa would have been flatter, wet and covered in forest .
  
highlights_snippet: Scientists say this marks a key point before the landscape began to rise .
  
highlights_snippet: this caused the climate to dry and the habitat to become less forested .
  