Room for expansion, not survival of the fittest, is the driving force behind evolution, according to a new study. The researchers—who say their findings cast doubt on one of the cornerstones of Charles Darwin's theories—studied evolutionary patterns over 400 million years and determined that biodiversity soared not when animals were forced to compete, but when animals moved into previously unoccupied areas, the BBC reports.
Mammals, the researchers note, only became so diverse when the dinosaurs were wiped out and they had plenty of living space to expand into. Other scientists say the findings are actually consistent with Darwin's theories. "What the authors have shown is that the diversification of species has gone hand-in-hand with the diversification of ecological roles those species fill," a biology professor tells the Vancouver Sun. "That's exactly what Darwin himself would have expected." (Read more Charles Darwin stories.)