A tiny creature that has not had sex for 100 million years has overturned the theory that animals need to mate to create variety. Analysis of the jaw shapes of bdelloid rotifers, combined with genetic data, revealed that the animals have diversified under pressure of natural selection. Researchers say that their study “refutes the idea that sex is necessary for diversification into evolutionary species”. The microscopic animals, less than four times the length of a human sperm, are all female, yet have evolved into different species that fill different ecological niches. Two sister species were found to be living...
