Metazoa Kingdom

Metazoa Kingdom: multicellular and heterotrophic animals

What is it - biological definition

Also known as the Animal Kingdom and the Animalia Kingdom, The Metazoa Kingdom is made up of multicellular living beings (composed of more than one cell) and heterotrophs (unable to make their own food).

Main phyla of the kingdom Metazoa and its characteristics:


- Amphibians: animals that have the ability to live in water and also on land. They breathe in water with gills and land with lungs. They also breathe through the skin. Examples: frogs, frogs and salamanders.

- Fish: live in water and have cold blood. They breathe through gills or gills. Examples: dogfish, shark, sardines, cod, trout, carp, sole, etc.

- Reptiles: cold-blooded animals. The skin is covered by bone plates or corneal scales. Examples: lizards, snakes, turtles, alligators, iguanas, etc.

- Mammals: They have mammary glands (females produce milk for puppies) and body temperature is controlled by the brain. The body of most mammals is covered by hair. Examples: human being, monkeys, horses, dogs, cats, lions, zebras, elephants, rhinos and etc.

- Birds: have the body covered by feathers, beak and pneumatic bones. They are oviparous (embryo develops within an egg) and warm-blooded. Examples: hawks, macaws, parrots, ducks, herons, geese, chickens, peacocks, turkeys, eagles and so on.


- Porifers: They have pores in the body through which nutrients and water circulate. Examples: sea sponges and limestone sponges.

- Shellfish: There are species of mollusks of aquatic life and others of terrestrial life. The body of these animals is soft and not segmented. Examples: octopus, squid, snail and etc.

- Annelids: are animals with their bodies divided into rings. Many species are hermaphrodites. Examples: earthworms, polychaetes and leeches.

- Cnidarian (coelenterates): they are aquatic life animals, that have gelatinous body and presence of stinging capsules. Examples: jellyfish, jellyfish and sea anemones.

- Flatworms: are parasites devoid of circulatory and respiratory system. The body of these animals has a flat shape and soft consistency. Examples: planarian, tapeworm and Schistosoma mansoni.

- Nematelmints: animals with elongated and cylindrical shape. They have complete digestive system and non-segmented body. Many parasitize humans. Examples: Ascaris lumbricoides, Oxyurus vermicularis and Ancylostoma duodenale.

- Arthropods: have external skeleton (exoskeleton) composed of chitin and body composed of head, thorax and abdomen. Arthropods are insects, crustaceans, arachnids and diplopods. Examples: flies, spiders, scorpions, centipedes, butterflies, crabs, crickets, beetles, among others.

- Echinoderms: animals that live in the sea. They have internal limestone skeleton. Examples: starfish, sea cucumbers and sea urchins.