For most of the inhabited Earth’s history, life is believed to have been represented by pre-nuclear and single-celled nuclear organisms. Then something happened and multicellular ones appeared. According to geological records, this happened 572-602 million years ago. According to bioinformatics, 250-286 million years ago.
Because of such vague terms, scientists decided to study the issue more carefully. Strangely, they concluded that the impetus for the development of life on Earth may have been the cryogenic period (635-720 million years ago), when the planet was covered in ice. For example, communities of microbes, associated dormant filter feeders, and active predators are now thriving in Antarctica. And all this despite the thick layer of ice.
Source: Ferra
