Numbers of Described Species by Taxonomic Group Taxonomic Group Approximate Number of Described Species Insects 751.000 Plants 248428 Noninsect Arthoropods(mites, spiders 123.151 crustaceans, etc.) Mollusks 50.000 46,983 Protozoa 30.800 Algae 26.900 Flat 12,200 Roundworms 12.000 Earthworms and related organisms 12.000 Birds 9.040 Jullyfish, corals, comb jellies 9.000 Reptiles 6300 Starfish, sea urchins, sand dollars, etc 6,100 Sponges 5000 Bacteria, blue-green algae 4.760 Amphibians 4.184 Mammals 4.000 Total 1380,902Numbers of Described Species by Taxonomic Group Taxonomic Group Approximate Number of Described Species Approximate Number of Described Species Insects 751,000 Plants 248,428 Noninsect Arthoropods (mites, spiders, crustaceans, etc.) 123,151 Mollusks 50,000 Fungi 46,983 Protozoa 30,800 Algae 26,900 Fish 19,056 Flatworms 12,200 Roundworms 12,000 Earthworms and related organisms 12,000 Birds 9,040 Jullyfish, corals, comb jellies 9,000 Reptiles 6,300 Starfish, sea urchins, sand dollars, etc. 6,100 Sponges 5,000 Bacteria, blue-green algae 4,760 Amphibians 4,184 Mammals 4,000 Total 1,380,902 1,380,902