Group Number of Described Species

The following are the number of group members of the described species . Bacteria and Blue - green Algae 4,760 ; Fungi 46,983 ; Algae 26,900 : Bryophytes ( mosses and liverworts ) 17,000 ; Gymnosperms ( conifers ) 750 : Angiosperms ( flowering plants ) 250,000 ; Protozoans 30,800 ; Sponges 5,000 ; Corals and Jellyfishes 9,000 ; Roundworms and Earthworms 24,000 ; Crustaceans 38,000 ; Insects 751,000 : Other Arthropods and Minor invertebrates 132,461 ; Molluscs 50,000 ; Starfishes 6,100 ; Fishes ( teleosts ) 19,056 ; Amphibians 4.184 ; Reptiles 6,300 ; Birds 9,198 and Mammals 4,170 . The total No. of species is 1,435,662 . About 1.8 million have been described by scientists ( Hilton - Taylor et al . 2008 ) , but conservative estimates suggest that there are 5-15 million species alive today ( May , 2000 ) , since many groups of organisms remain poorly studied . Over 15.000 new species are described every year ( Dirzo and Raven 2003 ; www.nature.com ) The 1.8 million species described by Science are incredibly diverse . They range from tiny , single - celled microbes like Nanoarchaeum equitans , 400 nm in diameter living as parasites on other microbes in thermal vents at temperatures of 70-98 ° C ( Huber et al . , 2002 ) . Since 2000 , 53 new species of primates have been described ( IUCN 2008 ) including a new species of Brazilian monkey , Mura's saddleback Tamarin . Invertebrates play a vital role in the survival of other living organisms . These are involved in keeping the environment active and provide us with rich soil , clean water and food . Herbivory is one of these services . Herbivores help the nature by releasing their faeces on the soil which is produced by eating plants etc. , after decomposition of the faeces the fertility of the soil increases . Herbivores also help in pollination , prunning the old parts of the plants and flowers . This phenomenon is helpful in the growth of new organs and parts and also helps in seed dispersal and parasitism etc. Invertebrates are widely present every where all around us on the earth . They have been recorded in the upper reaches of the atmosphere, in the driest deserts and in the cannopies of the wettest rainforests. They can even be found in the frozen Antarctic (some mites and springtails can withstand temperature of - 35°C) or on the ocean floor of the Abyssal Sea which reaches the depth up to 11,000 meters. Invertebrates are undisputed heavy weights of the planet. If we take the weight of the entire animal kingdom then arthropods alone will be of more than 85% of that weight. It is estimated that five to eight million insect species have not been identified or discovered, while approximately 10,000 species of chordates awaiting the discovery and description. A good number of oceanic speciės diversity still remains unidentified.