A Living Time Capsule Shows the Human Mark on Evolution - NYTimes.com

A Living Time Capsule Shows the Human Mark on Evolution - NYTimes.com: When Daphnia from the Middle Ages fed on the substance, they could hold onto much of it for days — a good strategy for surviving in a phosphorus-starved lake. “It was good at the time that they lived,” said Dagmar Frisch of the University of Oklohoma, a co-author on the study.

The more modern water fleas, on the other hand, used a different strategy. When they were put in phosphorus-rich water, they didn’t bother to hold onto it for long. With so much phosphorus on hand, they didn’t need to waste that energy.