How an embryo tells time

It is estimated that the majority of pregnancies that fail do so within the first seven days after fertilization, before the embryo implants into the uterus. In this time period, a complicated cascade of events occurs with ...

Fossil shark turns in to mystery pterosaur

Paleontologists have made a surprising discovery while searching through 100-year-old fossil collections from the UK—a new mystery species of pterosaur, unlike anything seen before.

page 1 from 9