We are supported by the skeleton within us, and it is continually changed by our experiences on Earth as we eat, drink, resist gravity, and age. Humans and all the mammals, reptiles, amphibians, and birds have inherited our skeleton from the first vertebrate ancestors that lived in the oceans more than 500 million years ago. Join me on a journey through half a billion years of the evolution of the skeleton, and an exploration of the comparative anatomy of amphibians, reptiles, birds, and mammals. Learn about the features of your human skeleton, how your bones allow you to explore Earth, and the ways that we can all support the integrity of our skeleton.