A new study suggests that ancient microbes once cast as oxygen haters may have actually learned to use the gas, offering a clue to how the first complex cells — and, eventually, all plants and ...

In the oceans and on land, scientists are discovering rare, transitional organisms that bridge the gap between Earth’s simplest cells and today’s complex ones.

Symbiotic bacteria living inside insect cells have lost much of their DNA over hundreds of millions of years, much like the ancient microbes that evolved into mitochondria ...

A virus that is big enough to be seen under an ordinary light microscope co-opts its host’s systems with the help of ...