Insects

Insects are invertebrates that are taxonomically referred to as the class Insecta. They are the most numerous and most widespread terrestrial taxon within the phylum Arthropoda. Insects are the most diverse group of animals on the earth, with around 925,000 species described—more than all other animal groups combined. Insects may be found in nearly all environments on the planet, although only a small number of species have adapted to life in the oceans where crustaceans tend to predominate. There are approximately 5,000 dragonfly species, 2,000 praying mantis, 20,000 grasshopper, 170,000 butterfly and moth, 120,000 fly, 82,000 true bug, 350,000 beetle, and 110,000 bee and ant species described to date. Estimates of the total number of current species, including those not yet known to science, range from two million to thirty million, with most authorities favoring a figure midway between these extremes. Adult modern insects range in size from 555 mm (see Phobaeticus serratipes) to 0.139 mm (see Dicopomorpha echmepterygis) The study of insects (from Latin insect, meaning "cut into sections") is called entomology, from the Greek εντομος, also meaning "cut into sections" [1].