Classifying animals

Classifying animals

We can classify animals in different ways. One way is to classify animals into vertebrates and invertebrates. Vertebrates have a backbone, and invertebrates don´t have a .
We can also classify vertebrates into five smaller groups: mammals, birds, fish, reptiles and amphibians.
There are different types of invertebrates. Some invertebrates have a shell, some have an exoskeleton and others have a soft body.
Dogs, dolphins and bats are mammals. Their are born live, and all baby mammals drink their mother´s . Most have four legs. All mammals breathe with their .
All have feathers, a beak and wings. Most birds can , but some can swim or run. All birds lay and breathe with their .
Most reptiles live on land. Some have covered in scales, but others have a shell. Some have legs and some reptiles have no . Reptiles lay and breathe with their .
Fish live in . They have fins, sacles and gills. They through their gills. Most fish lay .
Anphibians lay . Their babies live in and breathe through their gills. Adult live on land and in water. They through their lungs and moist skin. Adult amphibians have four .