The subject of systematic science is the classification of living organisms. Combining creatures into groups based on certain attributes is of great practical importance for their study. The main systematic categories of animals and the principles laid down in their classification will be considered in our article.
Animal classification basics
By what basis can animals be distinguished from the whole variety of living organisms? By the only way of feeding. All animals, from microscopic amoeba to giant whale, are heterotrophs. This means that they only eat ready-made organic substances and are not able to produce them on their own.
The smallest taxon of animals is the species. This is a group of individuals that are united according to the principle of similarity of structure, physiology and ecology. This systematic category of animals has a double name. It was first introduced into science by the famous scientist Karl Linnaeus. Cockchafer, migratory locust, polar owl - the first name is species. The second word defines the genus to which the animal belongs.
Systematic categories of animals: table
Systematic units are also called taxa. Species and genus are the smallest of them. The largest taxon is the kingdom. At the present stage of taxonomy, there are five of them. These are plants, fungi, bacteria, viruses and animals. Their main difference is the way of nutrition and structural features of the cell. The sequence of systematic categories of animals is given in our table.
Taxon name | Example |
View | European cat |
Kind | Cats |
Family | Feline |
Detachment | Predatory |
Class | Mammals |
A type | Chordate |
Kingdom | Animals |
Single cell
The systematic category of animals, which are protozoa, unites single-celled organisms. All of them are eukaryotes. Their cell is a holistic organism, capable of carrying out all the processes of life: nutrition, respiration, growth, reproduction, movement.
Typical examples of animals that belong to the kingdom of unicellular are amoeba proteus, green euglena, and ciliates.
Multicellular
The body of the representatives of this systematic unit is not just formed by many cells. These are the smallest structures, similar in structure and function, which are sequentially combined into tissues, organs and their systems. This systematic category of animals includes several types, the structure of which is sequentially complicated. There are seven of them. The most primitive in structure are sponges. These organisms lead an attached lifestyle, eating through filtering. Freshwater hydra, jellyfish, and polyps are representatives of the type Enteric. They have specialized cells that do not yet form real tissue.
For the first time, these structures appear in worms, which form several types of animals: flat, round and annular. Moreover, the latter are characterized by the appearance of the circulatory system. The next type of multicellular animals is called mollusks. They have a soft body that is not segmented and is often protected by a shell. The largest species diversity is the type of arthropod, which combines insects, crustaceans and arachnids.
Chordate
This systematic category of animals is the most complex and has a general structure plan. This is the presence of an axial cord, or chord, neural tube and gill slits in the pharynx. Depending on the habitat, they are modified. Representatives of the chord classes are known to all and are widely used by man in economic activities. These include typical aquatic inhabitants - fish, which are characterized by gill respiration. Amphibians live on land and breed in water bodies. These are frogs, toads and tree frogs. Reptiles — crocodiles, lizards, snakes, turtles — go completely to the land. And the air habitat obeyed the birds. The most highly organized animals of the chord type are mammals, of which man is also a representative.
So, living organisms, which are characterized by a heterotrophic type of nutrition, belong to the animal kingdom. Representatives of this systematic unit are combined in the following taxa:
- kingdom of unicellular;
- subdominance of multicellular.
The latter includes: sponges, intestinal, flat, round and annular worms, mollusks, arthropods, mammals.