These representatives of the Animal Kingdom can be found almost everywhere. Water, soil, other organisms, air ... We are talking about insects, the structural features of which we will study in our article.
Departments of the body and integument
Insects are distinguished by an enviable species diversity: approximately 1.5 million. Moreover, this figure is minimal. Despite this, they all have a common building plan. The body of insects is clearly divided into three sections. This is the head, chest and abdomen. The middle section carries three pairs of limbs and wings.
The internal organs of insects are reliably protected by the external skeleton - cuticle. Its outer layer is formed by fat-like substances that prevent excessive loss of moisture. Odorous or poisonous glands are located here. The color of the insect depends on the type of pigment in the middle layer of the cuticle.
Musculature
The insect muscles are unique. They have extreme contraction power. Due to this, some insects can lift a load tens of times higher than their own. Another feature is the frequency of contractions. This leads to various forms of flight: active, progressive, passive, hovering. Shorten limbs and move skeletal muscle wings. It is formed by striated fabric. The heart of insects consists of muscle fibers coated with a layer of epithelium.
Nervous system and sensory organs
These representatives of the Arthropod type are characterized by complex behavior. There are many examples of insects that are public: bees, bumblebees, termites, ants. They live in whole groups in which each member has his own "responsibilities." All this is possible thanks to the development of the nervous system of insects. It is represented by the abdominal chain, in which the brain, segmental and sub-pharyngeal nodes - ganglia are distinguished.
The organs of vision are located on the head. These are simple and complex eyes. The latter form mosaic vision. Each small eye perceives only a part of the image, and in aggregate a real integral picture is formed.
On the head are also antennae, which are the organs of touch. Similar structures are evenly distributed over the entire surface of the body of insects. Nerve endings called receptors are suitable for them. They perceive various types of irritations: chemical, mechanical, temperature.
Digestion and excretion
The digestive tract of insects through type. A characteristic feature of insects is the presence of salivary glands and the absence of a liver. Some representatives have specialized glandular cells that also secrete enzymes.
Among insects, extra-intestinal digestion is also found. For example, the larvae of ladybugs inject enzymes into the victim’s body. So there is a digestion of their contents.
Malpighian vessels are the organs of isolation of insects. These are tubes, with the blind end facing the body cavity, and the reverse into the intestines. They receive hemolymph. From this fluid in methanephridia, the end products of metabolism are released, which are removed through the intestines.
Circulatory and respiratory system
These systems are functionally interconnected. The main organ of blood circulation of insects is the only spinal vessel. This is a hollow muscle tube. Its posterior section is the heart of insects, and the anterior is the aorta.
Free-living species breathe with trachea. They open outward with special openings called spiracles. Through them, oxygen from the atmosphere penetrates into the trachea, then into their branches - tracheoles, and as a result they end up inside the cells. Here is the oxidation of organic substances.
Carbon dioxide removal can occur in the opposite direction through the spiracles,
Insect heart
This organ, which is a tube, consists of several pulsating chambers. Each of them corresponds to a specific segment of the body. Part of the abdominal region is the aorta.
The circulatory system of these animals is open. The heart of insects has a number of holes. They are called stomata or ostia. Through them, blood flows from the body cavity into the heart, due to the contractions of its chambers.
Reproduction and development
All insects are dioecious. In some species, sexual dimorphism is clearly manifested - a difference in the morphological characters of individuals of different sexes. Examples of insects in which dimorphism is observed are beetles - deer, dragonflies, butterflies.
Another characteristic feature is internal fertilization. This means that the fusion of gametes in insects occurs inside the female body. But further development can occur in different ways. In some species, individuals appear from the egg, which in appearance do not differ from adults. These are insects with incomplete transformation.
The larvae of butterflies, beetles, ants, mosquitoes develop with metamorphosis. Each of us saw the tracks. These are butterfly larvae. At a certain stage of development, they turn into a chrysalis. This is a resting stage of development. The doll turns into an adult, which goes on to an active lifestyle.
So, insects are representatives of the Arthropod type, which are characterized by the following symptoms:
- The body consists of three sections: head, trunk and abdomen.
- The integument is represented by the outer skeleton - cuticle.
- The circulatory system is open, the heart has the appearance of a tube consisting of several chambers.
- Excretory organs - numerous malpighian vessels, respiration - tracheids.