What structural features are characteristic of representatives of the arachnid class?

1) What structural features are characteristic of representatives of the arachnid class? 2) What departments does the spider’s body consist of? 3) How many limbs does a spider have, what are they called and what function do they perform? 4) What is the knowledge of chelicera? 5) What sense organs does a spider have? 6) How does the spider’s digestive system work? 7) What do arachnids eat? 8) Describe the respiratory organs of spiders. 9) How does arachnids develop?

1. The structural features of representatives of the class of arachnids include the fact that they have no antennae and no compound eyes.

2. The body of arachnids consists of the cephalothorax and abdomen.

3. The spider has 6 (six) pairs of limbs. Walking legs – 4 (four) pairs, are used to move. Pedipalps – 1 (one) pair, are used to capture and hold prey. Chelicera – 1 (one) pair, serve to grind food.

4. The value of chelicera is expressed in chopping food.

5. The most developed in arachnids is the sense of touch, carried out by means of sensitive hairs located throughout the body. Organs of vision are simple eyes. There are also organs of chemical composition in the form of cracks in the integument on the surface of the body.

6. Arachnids have extraintestinal digestion. The digestive system of arachnids consists of the anterior, middle and posterior sections. The anterior section is the pharynx and stomach. The middle section is the midgut. The back section is the rectum.

7. Almost all arachnids are predators and feed mainly on insects and other arthropods.

8. The respiratory organs are the pulmonary sacs and trachea. In different species, one of the types of respiration is found, as well as both types.

9. In arachnids, predominantly direct development.