A worm is like an insect, which refers to invertebrate animals that live in water bodies, land and inside a living organism, but in fact they do not belong to them. That type of worms that lives inside a living organism leads a parasitic lifestyle, fulfilling its needs at the expense of another animal. Most often, a person acts as the carrier of such worms.
All worms can be divided into three types: annular, round and flat worms. Many encyclopedias cannot determine which tapeworm belongs to which class. Some sources distinguish it in a separate type, while others consider it a subspecies of flatworms. But the fact remains that no one denies the existence of these worms.
Flatworms
Flatworms look very unusual. They have a pronounced front and rear parts of the body and, despite the strong flatness of the entire worm, the head and tail stand out strongly. Flatworms breathe the entire surface of the body, so they do not have respiratory organs and blood vessels.
The mouth of these worms is located on the abdomen. To him is the opening of the intestine. This feature helps them absorb the necessary nutrients from the environment. Those representatives of the species who lead a parasitic lifestyle, suck food from the body of another animal. With the help of the senses, flatworms are well oriented in space.
This type of worms includes: hepatic fluke, wide ribbon, milk planaria and so on.
Tapeworms
Tapeworms have a long, ribbon-shaped body divided into many segments. The front of the body begins with the head (scolex), which helps to stick to the organs of its carrier.
Their lifestyle determined the structure of the whole body. They parasitize even inside insects. This worm fulfills all its needs at the expense of a living organism, in whose organs it usually lives. The path of the parasite is degradation. Therefore, over time, these worms have lost all digestive organs, the ability to feel. Their nervous system was greatly simplified. The whole body of the worm has adapted to perform two main functions - this is nutrition and reproduction. It absorbs the necessary substances with the help of the head, suction cups and the surface of the whole body. And many higher animals will envy such developed reproductive organs.
The most famous representatives of the species: bovine and pork tapeworm, echinococcus, sheep’s brain and so on.
Roundworms
The most numerous type of worms, including more than 1 million species of invertebrates. They have an oval oblong body, gradually narrowing to the front and rear ends. They are called round because if you cut one worm across, you can see a clearly defined circle.
They breathe the entire surface of the body, therefore they do not have respiratory organs and blood vessels. The digestive system is very simplified, presented in the form of a mouth and anus, between which there is an esophagus, consisting of a straight tube.
This is a special representative of the animal world. In fact, such a worm as an insect is a versatile person. You can count on the fingers how many living creatures could simultaneously master the land, water and internal environment of a living organism. Roundworms are included in this number.
The squad of roundworms includes: ascariasis, bunostomosis, pinworms, worms and so on.
Annelids
The most famous representative of the species is the earthworm. Its appearance can help make an impression of how these worms look. Many flora and fauna researchers are interested in the question: is the earthworm an insect or not? If you delve into the very essence of their existence, then the worms interact perfectly with many insects, plowing the ground and fertilizing it with their own manure, making life easier for all plants and trees. Even at the larval stage, almost all insects resemble worms. But in fact, worms are not insects. These are two completely different types of representatives of the animal world.
A curious subspecies of the earthworm is a dung worm. In fact, this is the same earthworm, only larger and more energetic. Dung worm is more demanding on the composition of the soil, and retains all its qualities only in a fertilized and nutrient-rich land. Such worms are very fond of fish, so it is popular among fishermen.
In particular, among earthworms you can find: green, red, or rather fetid representatives.