evolution

Cells in symbiotic partnership, sometimes nested one within the other and functioning like organelles, can borrow from their host’s genes to complete their own metabolic pathways.

Only 170 million years ago, new plankton evolved. Their demand for carbon and calcium permanently transformed the seas as homes for life.

Clues from fish diversity suggest that interbreeding between species could be a major mechanism of fast speciation.

Modern humans and more ancient hominins interbred many times throughout Eurasia and Africa, and the genetic flow went both ways.

Researchers agree it’s a long shot, but transmissible cancers could theoretically evolve into independent species. Certain weird parasites might be living proof.

Theories about how animals became multicellular are shifting as researchers find greater complexity in our single-celled ancestors.

Researchers struggle to incorporate ongoing evolutionary discoveries into an animal classification scheme older than Darwin.

Contrary to popular belief, bacteria have organelles too. Scientists are now studying them for insights into how complex cells evolved.

Viruses and other parasites may sync with their host’s biological clock — or reset it — to gain an advantage.