subject = biologytitle = Biology InstinctInsects are neumeroutinvertebrate animals that belong in the Phylum Arthropoda and Class Insecta.The class Insecta is divided into 2 subclasses: Apterygota, or winglessinsects, and Pterygota, or winged insects. Subclass Pterygota is futher dividedon basis of metamorphosis. Insects that have undergone incomplete metamorphosisare the Exopterygota. Insects that undergo complete metamorphosis are theEndopterygota.Insects have an outer bilateral exoskeleton to which themuscles are attached to and provides protection for internal organs. Thebody is divided into 3 main parts which are the head, which include mouthparts,eyes, and antennae; thorax, which operate the jointed legs and /or wings;and abdomen, which has organs for digested food, reproducing, and gettingrid of waste products.

The major systems in insects are the circulatory,respiratory, nervous, muscular, digestive, and reproductive systems. In thecirculatory system, blood is pumped by the heart in a tube to the aorta,the head, and to other organs then enters the ostia openings along the sidesof the tube back to the heart. The respiratory systems carries O2 to cellsand takes away CO2 from cells through branching out to call cells of body.The nervous system consists of a brain receiving information from eyes, antennae,and controls the whole body and 2 nerve cords containing ganglia fused togetherto control activities of the segment without the help of the brain.

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insectmuscular system is made up of a few thousand samll but string muscles allowingthe insect to carry objects heavier than it. The digestive system is basicallya long tube where food enters the mouth to the crop where it is stored, gizzardwhere it is grinded, stomach where it is digested, then the undigested partsand wastes are moved to the intestine, colon then released at the anus. Andin the reproductive system, a new individual is produced sexually when thefemale eggs produced in the ovaries united with male sperm produced in thetestes.Both man and insect live almost everywhere, eat all kinds of food,and use all kinds of materials to build homes so they constantly live inconflict. Some insects seriously affect man’s health and are parasitic onman and other animals. insects that feed on human or animal blood can carrydisease in their salivary juices and spread the disease to other animals.Many insects irritate us without disturbing our health. Some bite and sting,and some people are allergic to them and some insects are injurious to ouragricultural crops, food products, clothing, and wooden buildings.

So farman has only partial success in defending against insects. But some insectsspecies are beneficial to man. The honey bee, for example, supplies us withhoney and the silkworm supplies us with silk. So bugs really aren’t thatbad.