Animal Evolution

Animals are creatures that breathe oxygen. They have to eat plants or other animals to survive.
Animals have been on earth for about 700,000,000 years. The first animals were tiny single celled creatures. Today , there are over 10 millions different species of animals. Like all living things, animals show similarities and differences that enable them to be classified into groups. Birds for example are the only animals that have feathers, while mammals are the only ones that have fur. The scientific

Presently , animals are classified according to a broader range of characteristics including their internal anatomy , patterns of development  , and genetic makeup. These features provide a much more reliable guide to an animal's place in the living world. They also help to show how different species are linked through evolution.

In 1735 a swedish naturalist, Carolus Linnaeus developed a system of classifying and naming all plants and animals. He used scientific terms ,usually from Latin of Greek, to name living things.