The animal kingdom is a vast classification of all living things on the earth. The kingdom Animalia encompasses all of the species present. Different genus, families, classes, order, and phyla are used to categorize the members of such a family. The presence or absence of the notochord is one of the most significant characteristics of animal categorization.
A notochord is a substance that is mainly composed of cartilage-like material. Chordates are creatures that have notochords on their backs.
Features of non-chordates
Chordates are animals that have notochords on their backsides. Instead, members of this species have slits in their gills and hollow nerve cords.
The lack or existence of the spinal cord is used to categorize all animals on the earth. Animals having backbones are classified as vertebrates, whereas those without are classified as non-vertebrates. Vertebrates are classified into seven different groups.
Fish are creatures with gills and no digits on their limbs. Pisces contains the most diverse vertebrate population, with approximately 30000 distinct species. Nearly 41% of living beings live in freshwater, whereas 58 per cent choose to live in an aquatic environment. The remaining 1% may live in both marine and freshwater environments. The head, body, and tail are the three major components of their bodily structure.
Amphibians have the potential to live on land and in water. They have a history of having a "double life." There are nearly 900 different species. Toads, frogs, and salamanders are examples of amphibians. Gills and lungs are both present in amphibians. They breathe via their gills as larval, and then their gills are replaced by lungs as adults.
Crocodiles, snakes, lizards, and other reptiles are classified as reptilia. There are over 1000 distinct animal species that fit under this group. They are split into the following categories:
Birds are a family of cold-blooded, bipedal, feathery creatures. However, they do have a unique ability to keep their body temperature consistent. The limbs on the front side of its body are designed to seem like wings. The majority of these creatures can fly. There are a few exceptions, such as ostriches, kiwis, and other birds that cannot fly. There are about 9000 species of Aves in all.
Mammalians are the creatures that belong to the Mammalian class. They are warm-blooded creatures, so their body temperature remains constant regardless of the situation. The occurrence of body hair and milk distinguishes them. They are the ones giving birth to the babies. Mammalia is the classification for humans. There are over 4000 mammalian species that have been identified so far. Lions, dogs, humans, and other mammals are examples of mammals.
The duck-billed platypus being the exception since it has both reptile and mammalian characteristics.
Until recently, all of the organisms that exist in our world have been divided into five groups. And the animal world is a component of it, including a wide range of organisms. The relative importance of the vertebrae determines the basic foundation of animal division.