Fossils from some of the oldest-known animals on Earth, dating from 574 million years ago (Ediacaran period), suggest that cloning, not competition, dominated the Ediacaran seas, slowing evolution until environmental stress helped drive the rise of sexual reproduction and a burst of biodiversity. Artist’s reconstruction of the Fractofusus community: the bottom right features a large Fractofusus around which there are 5 to 8 medium specimens clustered;...
