Crash Course Zoology - Season 1 Episode 3 Diversity of Bodies & Sizes

In this episode, we take a look at the various ways animals can grow, learn how and why some animals evolved to have a head and others evolved to not have a head, and examine the different types of skeletons - from those inside bodies (like our own), to skeletons outside bodies (like in insects), and even those made of water (like in jellyfish).