|The Open Door Web Site|
Groups of Animals
Because there are so many different types of animals in the world biologists have sorted them into groups. This is called classifying. The two main groups of animals are vertebrates and invertebrates.
We must be careful when we make a list of their differences. It is easy to say that all fish swim. The problem is that amphibians, such as the frog, also swim. Whales and dolphins swim and they are mammals. many insects swim. It is easy to think that 'all birds fly' but the ostrich and the penguin do not fly. On the other hand, there is a fish and there is a squirrel which can glide through the air! A lot of insects can fly. Biologists have to be very careful when they decide on reasons for putting animals into groups.
The images hyperlink to more information about each group.
The images hyperlink to more information about each group