Shell, beak, tusk: shared traits and the wonders of adaptation

We think of evolution as a tree with branches that make clear, linear sense - with one animal and its traits clearly derived from one that came before it genetically.

But what about animals who share key traits but aren't on the same family tree?

This is called convergent evolution, and it's the big idea that Bridget Heos tackles in a kid-friendly way in Shell, Beak, Tusk.