The five groups of vertebrates
Biology · Key Stage 2 · The School
What a vertebrate is
A VERTEBRATE is any animal with a backbone inside it. Humans are vertebrates. So are birds, fish, and frogs. All vertebrates are sorted into five main groups. Each group shares certain features that make it easy to tell apart from the others. Scientists have used this same system for a very long time. It still works well today.
Fish, amphibians and reptiles
FISH live in water and breathe through gills. AMPHIBIANS, like frogs, start life in water and move onto land as adults. REPTILES, like lizards and snakes, have dry, scaly skin and usually lay eggs on land, not in water. Each group has features suited to how it lives.
Birds and mammals
BIRDS have feathers and a beak, and almost all of them can fly. MAMMALS have fur or hair, and feed their young on milk. Humans are mammals. So are dogs, whales and bats, even though they look extremely different from each other. A penguin cannot fly, but it still counts as a bird, feathers and all.
A trout lives underwater and breathes with gills. That makes it a FISH. A frog starts life in a pond, then grows legs and moves onto land. That makes it an AMPHIBIAN. A snake has dry, scaly skin and lays eggs on land. That makes it a REPTILE. A robin has feathers and a beak. That makes it a BIRD. A rabbit has fur and feeds its babies milk. That makes it a MAMMAL. Five very different animals, each one sorted using just one or two clear features.