Animal
Wiki, Facts

 Animal facts

• 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 542 million years ago
• Animals can be divided broadly into vertebrates and invertebrates
• Vertebrates have a backbone or spine (vertebral column), and 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, leeches), cnidarians (jellyfish, sea anemones, corals), and sponges
• The study of animals is called zoology