Barcode of Life Data Systems (BOLD) Stats Specimen Records:3808262 Specimens with Sequences:3121047 Specimens with Barcodes:2870275 Species:219540 Species With Barcodes:190600 Public Records:2754415 Public Species:91064 Public BINs:298550
The arthropods are the most successful type of organism known so far - if you define success by the number of known species. Almost half of the described species are arthropods, and given the rate at which scientists find new species, we can presume that we have described less than one fifth of the species out there. They are bilaterally symmetrical (there is a left/right symmetry), their bodies are made up from a series of segments, and they have paired and usually jointed appendages on some or all of the body segments. The body is protected by a tough organic or organic-mineral cuticle which functions as an exoskeleton. In order to grow, arthropods periodically shed their cuticle by a process called ecdysis. Insects, spiders, crustacea, trilobites are all types of arthropods.
Based on studies in: USA: Alaska, Barrow (Tundra) USA: California, Cabrillo Point (Grassland) USA: California, Coachella Valley (Desert or dune) USA: Wisconsin, Little Rock Lake (Lake or pond)
This list may not be complete but is based on published studies.
J. Brown, The structure and function of the tundra ecosystem, U.S. Tundra Biome 1971 Progress Rept. 1 (1971).
L. D. Harris and L. Paur, A quantitative food web analysis of a shortgrass community, Technical Report No. 154, Grassland Biome. U.S. International Biological Program (1972), from p. 17.
Polis GA (1991) Complex desert food webs: an empirical critique of food web theory. Am Nat 138:123155
Martinez ND (1991) Artifacts or attributes? Effects of resolution on the Little Rock Lake food web. Ecol Monogr 61:367392
Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2006. The Animal Diversity Web (online). Accessed February 16, 2011 at http://animaldiversity.org. http://www.animaldiversity.org