looking into a viewer visitors can observe a tiny freshwater animal,
called a rotifer that reproduces without a partner. These multicellular
organisms haven't reproduced with a partner in nearly 40 million
years. Male rotifers don't exist anymore. Biologists don't understand
why rotifers stopped using sex with all its advantages. By mixing
the genes of two parents, sex increases the diversity in the offspring.
Biologists believe this diversity could be beneficial in a changing
environment. Species with lots of unique individuals are more likely
to have at least some individuals survive shifting environments.
Yet the rotifers gave up that advantage, and are doing just fine.