Birds do it, and bees do it. Indeed, researchers estimate that over 99.9% of eukaryotes reproduce sexually. What, then, are the true costs and benefits of sex? Yet again, this simple example ...

The staggering array of modern dog breeds is typically traced to the Victorian era. But half of all canine variation was in place roughly 10,000 years ago, a new study suggests. By Emily Anthes As a ...

This question originally appeared on Quora. Answer by Suzanne Sadedin, Ph.D. in zoology from Monash University: Lifespan in general is determined by trade-offs between survival and reproduction.