Arthropoda

Diversity

Arthropoda is the largest animal phylum, with the estimates of the number of arthropod species varying from 1,170,000 to 5~10 million and accounting for over 80 percent of all known living animal species. One arthropod sub-group, the insects, includes more described species than any other taxonomic class. The total number of species remains difficult to determine, as estimates rely on census counts at specific locations, scaled up and projected onto other regions, then totalled – allowing for double-counting – to cover the whole world. Modeling assumptions are involved at each stage, introducing uncertainty. A study in 1992 estimated that there were 500,000 species of animals and plants in Costa Rica alone, of which 365,000 were arthropods.