Sorting the animal kingdom — plus skeletons, food chains and adaptation.
Scientists sort animals into groups by what they have in common. Animals with a backbone are called vertebrates, and they split into five groups.
Animals with no backbone (like insects, worms and snails) are invertebrates.
A skeleton supports the body, protects the organs, and helps an animal move. Vertebrates have their skeleton inside (an endoskeleton). Many invertebrates, like beetles, have a hard shell outside (an exoskeleton).
A food chain shows who eats what. The arrow means "is eaten by":
An adaptation is a feature that helps an animal survive in its habitat. A polar bear has thick fur for the cold; a camel stores fat in its hump for the desert; a duck has webbed feet for swimming.