After a monster meteor crashed into Earth some 65 million years ago and wiped out the dinosaurs and the vast majority of all other life on the planet, it took millions of years for the pace of evolution to pick up and the ancestors of modern animal species to begin diversifying rapidly and radiating throughout the world.
The timing of species development after the crash has long been a mystery to scientists, with many believing that the Great Extinction allowed an immediate speedup in evolution's pace.
But an international research team, creating a "supertree" to chronicle the evolution of nearly all the 4,500 species of mammals alive today, has concluded that the meteor disaster was followed only by a brief interval of evolution and extinction. It took tens of millions of years after that for all the mammalian species -- and probably the birds, too -- to begin their full-paced evolutionary advance, they say.
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