Sentences with phrase «modern animals suddenly»
These proxies seemed to indicate that oxygen concentrations in the oceans rose in several steps, approaching today's sea - surface concentrations at the start of the Cambrian, around 541 million years ago — just before more - modern animals suddenly appeared and diversified.
https://www.scientificamerican.com/ Not exact matches
First transmitted on Channel Four / Equinox, December 2001 How changes to the world's forests and oceans could trigger a rapid acceleration of global warming 55 million years ago, something strange happened to life on Earth: many animals suddenly shrank, with horses becoming the size of modern domestic cats.