Arthropoda

Arthropoda is the phylum of the greatest in the world of animals and include insects , spiders , shrimp and other similar animals. Arthropods commonly found in marine, freshwater, land and air environments, including various symbiotic and parasitic forms. Nearly 90% of all known species of animals are arthropods.

Characteristics that distinguish the phylum arthropods were: body segmented, the segments usually unite into two or three clear areas, segmented limbs in pairs (Originally naming Arthropoda), bilateral symmetry, berkitin exoskeleton. Flow periodically and updated as the growth of animals, such as pipes alimentari canal with mouth and anus, open circulatory system, blood vessels are normally only tangible dorsal structures such as a pipe to channel alimentar with lateral openings in the abdomen, the body cavity; a blood cavity or hemosol and coelomic reduced. The nervous system consists of an anterior ganglion or brain located above the canal.
alimentari, a pair of connecting the channel from the brain to the rope around the canal and the nerve ganglion alimentari located below the alimentary canal, Malpighian tubule excretion usually by. Empty tubes that enter the canal alimentari and excretion of the material passing out through the anus, respiration with gills or trachea and spiracles, no cilia or nefridia. Anthropoda nervous system such as the annellida, there is the ventral part of the body is shaped like a rope ladder.

Arthropods have four classes, among which are:

1. Class Myriapoda.
2. Class Crustacea.
3. Arachnid class.
4. Class Insecta.

Four of the five parts of the animal species are arthropods, with over a million modern species are discovered and the fossil record is reached early Cambrian . Arthropods commonly found in marine, freshwater, land and air environments, as well as including various symbiotic and parasitic forms. Nearly 90% of all known species of animals are arthropods. Arthropods are considered closely related to annelids, for example, is Peripetus in South Africa. Arthropod phylum in the animal world is the largest in the world. Number of species is about 900,000 with a wide variety of species. This amount is approximately 80% of animal species known today. Arthropods can live in freshwater, marine, land, and practically all of the Earth's surface is filled by this species. Arthropods may be the only one who can live in Antarctica and burrows in the steep rocks of high mountains. All members of this phylum have jointed bodies and outer skeleton composed of chitin. The main body cavity called a hemocoel. Hemocoel consists of a small room that is pumped by the heart. The heart lies on the dorsal side of the body.