'True grit' erodes assumptions about evolution

New work in Argentina where scientists had previously thought Earth's first grasslands emerged 38 million years ago, shows the area at the time covered with tropical forests rich with palms, bamboos and gingers. Grit and volcanic ash in those forests could have caused the evolution of teeth in horse-like animals that scientists mistakenly thought were adaptations in response to emerging grasslands.

Fuente : http://www.eurekalert.org/pub_releases/2013-03/uow...