Types of animals: examples, classification

On planet Earth, there are an infinite number of species of diverse animals. In order to understand them, it is worth studying the classification, which includes types, classes and units. Species are the last step of division, and therefore their number is so great. It is better to take a few basic types of animals, which are much smaller. To study the species included in them will be much more convenient.

Sponges

For a long time these animals were considered plants. Science has studied their structure quite recently. The sponge type includes a variety of animal species. Examples of them can be listed for a very long time. Representatives always live in an aquatic environment, but they outwardly differ in a very impressive way. Sponges can look like inexpressive growths, flat cakes, twigs or lumps. The glassy look of these animals looks incredibly beautiful and is a true masterpiece of nature - the so-called basket of Venus or sea orange seem openwork and translucent. They also have common features - for example, sponges do not move much. Nevertheless, each species knows how to get food without problems - by passing through the body of impressive volumes of water, microorganisms from which are the diet of these bizarre creatures. But the most interesting is that the coincidence of the names of these animals with the name of household items for washing or cleaning is not accidental: earlier in this purpose they used live sponges that are useful for the skin and can be very gentle to the touch.

Coelenterates

So, listing the species of animals, examples should be divided into categories according to their main types. The next - coelenterates, low-organized beings, whose bodies consist of only two layers of cells. All their species, with a few exceptions, live in an aquatic environment. For example, it is the hydroid of the Eudendrium, the coral of the acropora or the siphonophor of the physeophore. Each of these species has a unique appearance - some look like small trees, while others look like bird feathers. Unites their habit of living in colonies and the structure of the body - as is obvious from the name, the only body cavity is the intestine. All species can be divided into two groups: polyps, located at a certain place, or jellyfish, which can be mobile.

Worms

Enumerating species of animals, the list of which is very long, it is worth mentioning this type. Worms can be flat, ringed and round. All these species unite the structure of several layers of cells - ectoderm, endoderm and mesoderm. There are no cavities of the body in worms, the body consists of a parenchyma that performs all the necessary functions. However, there is a difference between these species. Flat worms have a brain stem, in round there are only a few longitudinal and okologlotenochnye nerve rings, and in the ringed - the abdominal nervous system. In addition, the latter have a closed circulatory system, which the others do not have.

Shellfish

It is worth studying not only primitive species of animals. Classification includes much more developed organisms, for example, mollusks. This is the type that includes the maximum number of species. These are organisms that live in the sea (oysters, octopuses, mussels, squids), fresh water (bezbuki, vivipants, pond snails) or in moist soil (snails, slugs). The sizes of mollusks of different species are very different, they can be quite tiny (just a few millimeters) or reach more than twenty meters in length. Many lead a sedentary lifestyle, but some can move in a reactive way. These are squid and similar animal species. The classification of mollusks also includes such variants as cephalopods, bivalves and gastropods. Some have a shell consisting of several layers (horny and calcareous), but many lost it in the course of evolution. Combines all these species of animals, whose names, by the way, include snails, squid and the structure of the digestive system. It consists of three divisions with anterior, middle and posterior intestine. Some individuals differ muscular tongue with denticles, while others feed passively, simply by filtering the food out of the aqueous suspension with gills. In all species, the circulatory system is not closed and includes vessels and a heart with several atria and a ventricle. Aquatic organisms breathe gills, terrestrial - lungs. The excretory system is represented by the kidneys, and the nervous system is represented by scattered nodes with several large ganglia.

Arthropods

Enumerating various species of animals, the list can not be completed without mentioning these organisms. Arthropods are the centipedes, scorpions, spiders, and crayfish. As a rule, these are two-sidedly symmetrical animals with a body divided into segments. The body is covered with a cuticle made of chitin, which serves as the outer skeleton and protection for the body. Since this category includes a variety of animal species, examples of the respiratory system can be diametrically opposed - these are both the lungs and the gills. All representatives have an unclosed circulatory system. The shape of the body can be varied. Typically, the body consists of several segments: the head, chest and abdomen - they have all these kinds of animals. Examples, however, include some variations: in spiders, the head and chest are combined with the abdomen, while in the mites segments can not be isolated at all.

Chord

The most common and known species of animals, photos of which everyone saw, belong to this type. It is supreme and assumes the presence of a skeletal axis, a neural tube. The type includes three main types of organisms: shells, cranial and vertebral. The first species of animals, examples of which are much less known than the latter, most often live in an aquatic environment and settle in colonies. They have barrel-like or sack-shaped bodies, a nervous system of the ganglion and underdeveloped sense organs. Such organisms include the following species: ascidians, appendicularia, pyrosomes and others. These creatures multiply in different ways, feed on algae, small animals, detritus. Interestingly, the adult form is simplified, but larvae are much more active and differ in developed sense organs. Cranial do not have a separate head, which determines their name. Breathe in gills and have not too many representatives, the most famous is the lancelet. Finally, vertebrates are the most famous and developed group of animals. There are all kinds of mammals, fish, birds, amphibians and reptiles. This type developed back in prehistoric times. At the moment, people know about fifty thousand species of vertebrates.