U. BUFFALO (US) — Following one of Earth’s greatest mass extinctions, a type of tiny marine organism didn’t begin to rapidly develop new physical traits until about 2 million years after its competition became extinct.
The discovery challenges the widely held assumption that a period of explosive evolution quickly follows for survivors of mass extinctions.
In the absence of competition, the common theory goes, surviving species hurry to adapt, evolving new physical attributes to take advantage of newly opened niches in the ecosystem. But that’s not what researchers found in graptoloid populations that survived a mass extinction about 445 million years ago.
“What we found is more consistent with a different theory, which says you might expect an evolutionary lag as the ecosystem reforms itself and new interspecies relationships form,” says Charles E. Mitchell, geology professor at the University at Buffalo who led the research.
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