InsectsInsects are neumerout invertebrate animals that belong in the Phylum Arthropodaand Class Insecta.
The class Insecta is divided into 2 subclasses: Apterygota,or wingless insects, and Pterygota, or winged insects. Subclass Pterygota isfuther divided on basis of metamorphosis. Insects that have undergone incompletemetamorphosis are the Exopterygota. Insects that undergo complete metamorphosisare the Endopterygota. Insects have an outer bilateral exoskeleton to which the muscles are attachedto and provides protection for internal organs. The body is divided into 3 mainparts which are the head, which include mouthparts, eyes, and antennae; thorax,which operate the jointed legs and /or wings; and abdomen, which has organs fordigested food, reproducing, and getting rid of waste products.Order now
The major systems in insects are the circulatory, respiratory, nervous,muscular, digestive, and reproductive systems. In the circulatory system, bloodis pumped by the heart in a tube to the aorta, the head, and to other organsthen enters the ostia openings along the sides of the tube back to the heart. The respiratory systems carries O2 to cells and takes away CO2 from cellsthrough branching out to call cells of body. The nervous system consists of abrain receiving information from eyes, antennae, and controls the whole body and2 nerve cords containing ganglia fused together to control activities of thesegment without the help of the brain.
insect muscular system is made up of afew thousand samll but string muscles allowing the insect to carry objectsheavier than it. The digestive system is basically a long tube where food entersthe mouth to the crop where it is stored, gizzard where it is grinded, stomachwhere it is digested, then the undigested parts and wastes are moved to theintestine, colon then released at the anus. And in the reproductive system, anew individual is produced sexually when the female eggs produced in the ovariesunited with male sperm produced in the testes. Both man and insect live almost everywhere, eat all kinds of food, and use allkinds of materials to build homes so they constantly live in conflict.
Someinsects seriously affect man’s health and are parasitic on man and other animals. insects that feed on human or animal blood can carry disease in their salivaryjuices and spread the disease to other animals. Many insects irritate us withoutdisturbing our health. Some bite and sting, and some people are allergic to themand some insects are injurious to our agricultural crops, food products,clothing, and wooden buildings.
So far man has only partial success in defendingagainst insects. But some insects species are beneficial to man. The honey bee,for example, supplies us with honey and the silkworm supplies us with silk. Sobugs really aren’t that bad.