What are the arthropods?

Arthropods are the main category of animals, including insects, arachnids, crustaceans, centipedes and several others. In Greek, Arthropod means a "joined leg", a reference to one of the defining characteristics of the phylum - a segmented body with an attachment. Arthropods are the most successful and diverse of all animals in terms of their number and ubiquity. They create about 80% of all animal species and more than a million were given by scientific names. They are covered with an exoskeleton made of chitin, a stiff polysaccharide that serves as a kind of armor and protects members from drying. When a member grows, he must shed her layers. In today's world, arthropods tend to be relatively small, generally less than half a meter, although several, like the Japanese crab of spiders, have a foot range of up to 3.5 m (12 ft). The smallest arthropods are planktonasi 300 microns of large.

Some ancient arthropods like jaekeLopterus , Scorpion and Arthropleura , related to the Centipede, approached 3 m (10 ft) and had more weight than today's largest arthropod. In general, oxygen levels are a limiting factor in the size of arthropods, as their open circulation systems are not as effective in circulating blood as closed circulation systems of many other animals. During the carbon period, 300 million years ago, the Earth had a greater oxygen level, allowing the existence of huge arthropods, especially insects such as a huge relative of dragonflies, meganeura

Arthropods are a very old phylum that extends to the Cambrians (535 million years ago) and maybe earlier. Trace fossils made by arthropods come from 535 million years and Spriggina , a mysterious trilobite precursor, which may be a member, dates 555 million years ago.

Arthropods thrive with heat and moisture. They follow every present strategy for feeding, from herbivorous to carnivorous to cleaning into parasiticists. AppearanceEm you are probably in the feet of several arthropods right now - most likely spiders.