Insects are neumerout invertebrate animals that belong in the Phylum Arthropoda and Class Insecta. The class Insecta is divided into 2 subclasses: Apterygota, or wingless insects, and Pterygota, or winged insects. Subclass Pterygota is futher divided on basis of metamorphosis. Insects that have undergone incomplete metamorphosis are the Exopterygota. Insects that undergo complete metamorphosis are the Endopterygota.
Insects have an outer bilateral exoskeleton to which the muscles are attached to and provides protection for internal organs. The body 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 getting rid of waste products.
The major systems in insects are the circulatory, respiratory, nervous, muscular, digestive, and reproductive systems. In the circulatory 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 sides of the tube back to the heart. The respiratory systems carries O2 to cells and 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 together to control activities of the segment without the help of the brain. insect muscular system is made up of a few thousand samll but string muscles allowing the insect to carry objects heavier than it. The digestive system is basically a long tube where food enters the mouth to the crop where it is stored, gizzard where it is grinded, stomach where it is digested, then the undigested parts and wastes are moved to the intestine, colon then released at the anus. And in the reproductive system, a new individual is produced sexually when the female eggs produced in the ovaries united...
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