The Animal Kingdom , Animalia or Metazoa is composed of heterotrophic organisms, that is, those that do not produce their own food.
This is one of the main characteristics of the group and what sets them apart from other living things, such as vegetables.
The beings that belong to the animal kingdom are eukaryotes and multicellular . They have locomotion ability and most of them reproduce sexually.
Animals are classified into several phyla, many of them being invertebrate animals (those without vertebrae).
Vertebrate animals with skull, vertebrae and backbone belong to the Corded Phylum.
Embryonic development determines important characteristics for its classification, all animals have the stage of blastula in its development.
The animal kingdom is divided into several phyla. The main ones are: porifers, cnidaria, flatworm, nematode or nematelminth, annelid, echinoderms, molluscs, arthropods and chordates.
The vertebrate animals belong to the Cordado Phylum (Chordata). The main feature of the group is the presence of the spinal cord and spine.
Chordate animals are divided into 5 classes: fish, amphibians, reptiles, birds and mammals.
Fish are animals with scaled bodies and gill breathing (they take oxygen out of the water). They do not control body temperature (pylothermic). Examples of fish are the goldfish, the stingray and the shark.
Mammals have hair, are homeothermic and have pulmonary respiration. One of the main characteristics of the group is the fact that the females feed the pups through the mammary glands.
Examples of mammalian animals are humans, cats, dogs and bats.
Invertebrate animals are represented by numerous phyla with very different characteristics, but all are multicellular and have no cell wall .
There are eight phyla of invertebrate animals, namely: porifers, cnidaria, flatworms, nematelmints, mollusks, annelids, echinoderms and arthropods.
Porifers are primitive freshwater or saltwater animals. They are organisms that have no organs and no ability to move and reproduction can be sexual or asexual. Examples: sponges.
One feature that makes them peculiar is the presence of a specific cell type, the cnidocytes. Some examples of cnidaria are jellyfish, corals, sea anemones, hydras and caravels.
Nematodes or nematodes have a cylindrical body and can be free-living or parasitic to humans and plants. Examples are roundworms, oxyureas and other worms.
The annelids have a segmented body composed of rings. They live in moist habitats on land and in fresh or salt water. Examples are earthworms, polychaetes and leeches.
The echinoderms are marine animals with presence of calcareous exoskeleton and hydrovascular system. Their body has pentarradial symmetry, that is, with 5 equal sides. Examples are sea cucumbers, starfish and sea urchins.
Mollusks are soft-bodied animals with shells, which may be internal (squid and octopus) or external (snails, mussels). They inhabit fresh or saltwater environments and wetlands.
Examples of mollusks include mussels, octopuses, squids, slugs, oysters and snails.
Arthropods comprise a very diverse phylum. They are characterized by segmented body and presence of chitin exoskeleton.
The main arthropods are: