How Animals Survive
An animal also needs to be able to respond to its environment - for example, to find food or to run away from danger.
Adaptation is a characteristic that helps an organism survive in its environment or reproduce.
Classification of Animals
Biologists classify animals in the animal kingdom into about 35 phyla, or major groups.
Important characteristic used to classify animals is the presence or absence of a backbone.
Jellyfishes, worms, snails, crabs , spiders, and insects are invertebrates.
About 95% of animals are invertebrates.
Fishes amphibians, reptiles, birds, and mammals.