The animal kingdom is generally divided into 5 main categories.
- They are divided into 5 important classes, namely mammals.
Some animal species, such as Amphioxus, are called primitive chordates. They live permanently in the seas. There are skeletons only in the dorsal regions. Some characteristics of vertebrates:
* Roams are not open.
* There is a nerve cord and a nerve cord in the back.
* Respiratory organs are related to the pharynx.
To summarize; As far as is known, around 2 million species live within the living groups mentioned above. If we take into account the extinct species, the rate of living species that biologists must examine is understood. Here, this sweaty business has been facilitated, albeit partially, by “Biosystematics”.
In addition, animals are mostly non-mind creatures that move, that is, move around, take their food with organic matter, and guide their movements with their instincts. About one million animal species have been discovered today. There are some that are too small to be seen, such as amoeba, as well as those that have large structures such as elephants. Cats, horses, dogs and birds that we come across every day around us and that we can’t help but caress, are all vertebrates.
In addition, although some animals survive with difficult struggles, some animals continue their lives as parasites on other animals. The body structure of animals is suitable for the way they eat, the region where they live, and in short, the opportunities to continue their lives. If we examine the body structure of the animals we know closely, who eat meat and grass, we can clearly see this. The nails and claws of meat-eating animals such as cats and dogs are suitable for catching, their teeth are sharp and very sharp. The teeth and lips of animals like sheep and horses have been created in such a way that they can eat grass. Undoubtedly, the shape of the digestive organs of these animals is quite different.