The evolution of the anus may have guided the body plan of all developed animals, including people.
Mattlphotography / alamy
Anus is a crazy successful innovation, but how did it develop? A genetic analysis shows that it probably starts as an openness used to secrete sperm fused with the intestine – an example of the reorganized structures of evolution.
“When a hole is there, you can use it for other things,” he says Andreas Hejnol At the University of Bergen in Norway.
Early animals are thought to develop…
