Porifera cnidaria platyhelminthes nematoda és annelida
For other uses, see Animalia disambiguation. Animal diversity.
All animals are motile, meaning they can move spontaneously and independently at some point in their lives. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their lives.
All animals are heterotrophs: they must ingest other organisms or their products for sustenance. Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about million years ago.
Animals can be divided broadly into vertebrates and invertebrates. Vertebrates have a backbone or spine vertebral columnand amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals. The remaining animals are the invertebrates, which lack a backbone.
These include molluscs clams, oysters, octopuses, squid, snails ; arthropods millipedes, centipedes, insects, spiders, scorpions, crabs, lobsters, shrimp ; annelids earthworms, leechescnidarians jellyfish, sea anemones, coralsand sponges.