Evolution is perhaps the most extraordinary story ever told—a tale spanning billions of years that connects every living thing on Earth through an intricate web of shared ancestry. From the tiniest ...

From butterflies to blue whales, corals and worms, Earth is home to an incredible diversity of animals. How all of these animals evolved from earlier, simpler ancestors is one of the most exciting ...

Embryonic germ layers are the fundamental organizing principle in animal development. They provide the structural basis from which tissues and organs arise. During early embryogenesis, cells divide to ...