Animals are heterotrophic organisms, i.e., they require other organisms in order to obtain their food. They are multicellular and eukaryotic organisms (cells have a nucleus). Their shape and size vary widely, some colonial animals such as sponges and corals resemble plants.
Animals have traditionally been divided into vertebrates and invertebrates. Invertebrates range from sponges to insects, passing through several groups of earthworms, whereas vertebrates include fish, amphibians, reptiles, birds and mammals.
The diversity of animals in Mexico is one of the greatest in the world. Currently, around 73,000 species of animals have been described in Mexico. Globally, more than a million species of animals have been described, but it is estimated that total diversity is even greater.
|
