Lists of organisms by population explained

This is a collection of lists of organisms by their population. While most of the numbers are estimates, they have been made by the experts in their fields. Species population is a science falling under the purview of population ecology and biogeography. Individuals are counted by census, as carried out for the piping plover;^{[1] [2]} using the transect method, as done for the mountain plover;^[3] and beginning in 2012 by satellite, with the emperor penguin being first subject counted in this manner.^[4]

Number of species

More than 99 percent of all species, amounting to over five billion species,^[5] that ever lived on Earth are estimated to be extinct.^{[6] [7]} Estimates on the number of Earth's current species range from 10 million to 14 million,^[8] of which about 1.2 million have been documented and over 86 percent have not yet been described.^[9] According to another study, the number of described species has been estimated at 1,899,587.^[10] 2000–2009 saw approximately 17,000 species described per year.^[10] The total number of undescribed organisms is unknown, but marine microbial species alone could number 20,000,000.^[10] For this reason, the number of quantified species will always lag behind the number of described species, and species contained in these lists tend to be on the K side of the r/K selection continuum. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.^[11] The total number of related DNA base pairs on Earth is estimated at 5.0 x 10³⁷ and weighs 50 billion tonnes.^[12] In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion [million million] tonnes of carbon).^[13] In July 2016, scientists reported identifying a set of 355 genes from the Last universal common ancestor (LUCA) of all organisms living on Earth.^[14]

By domain

The domain of eukaryotes represent a small minority of the number of organisms; however, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes.^[15] Prokaryotes number about 4–6 × 10³⁰ cells and 350–550 Pg of C.^[16]

Microbes

It is estimated that the most numerous bacteria are of a species of the Pelagibacterales (or SAR11) clade, perhaps Pelagibacter ubique, and the most numerous viruses are bacteriophages infecting these species.^[17] It is estimated that the oceans contain about 2.4 × 10²⁸ (24 octillion) SAR11 cells.^[18] The Deep Carbon Observatory has been exploring living forms in the interior of the Earth. "Life in deep Earth totals 15 to 23 billion tons of carbon".^[19]

Animalia

Vertebrates

Mammals (Mammalia)

• Mammals by population
  • Artiodactyla
  • Carnivora
  • Cetacea
  • Chiroptera
  • Perissodactyla
  • Primates
  • Elephants
  • Marsupials

Birds (Aves)

• Birds by population
  • Anseriformes
  • Apodiformes
  • Caprimulgiformes
  • Charadriiformes
  • Ciconiiformes
  • Columbiformes
  • Coraciiformes
  • Cuculiformes
  • Falconiformes
  • Galliformes
    • The domesticated chicken (Gallus gallus domesticus), a Galliform, has an estimated population of 23.7 billion,^[20] which is higher than any other bird.^[21]
  • Gaviiformes
  • Gruiformes
  • Passeriformes
  • Pelecaniformes
  • Phoenicopteriformes
  • Piciformes
  • Podicipediformes
  • Procellariiformes
  • Psittaciformes
  • Sphenisciformes
  • Strigiformes
  • Struthioniformes
  • Tinamiformes
  • Trogoniformes

Reptiles (Reptilia)

Animal	Population	Notes
	100–200^[22]	Only in the wild. Chinese alligators are quite prolific in captivity, with estimates of the total captive population at over 10,000 animals, mostly in the Anhui Research Centre of Chinese Alligator Reproduction and the Madras Crocodile Bank.
	4,000–5,000	Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000).^[23] However, there are concerns that there may presently be only 350 breeding females.^[24]

Hexapoda

Insects (Insecta)

Recent figures indicate that there are more than 1.4 billion insects for each human on the planet,^[25] or roughly 10¹⁹ (10 quintillion) individual living insects on the earth at any given time.^[26] An article in The New York Times claimed that the world holds 300 pounds of insects for every pound of humans. Ants have colonised almost every landmass on Earth. Their population is estimated as between 10¹⁶–10¹⁷ (10-100 quadrillion).^[27] With an estimated 20 quadrillion ants their biomass comes to 12 megatons of dry carbon, which is more than all wild birds and non-human mammals combined.^{[28] [29] [30]}

Plantae

Trees

According to NASA in 2005, there were over 400 billion trees on our globe.^[31] However, more recently, in 2015, using better methods, the global tree count has been estimated at 3 trillion.^[32] Other studies show that the Amazonian forest alone yields approximately 430 billion trees.^[33] Extrapolations from data compiled over a period of 10 years suggest that greater Amazonia, which includes the Amazon Basin and the Guiana Shield, harbors around 390 billion individual trees.^[34]

See also

• Biomass (ecology)
• Largest organisms
• List of longest-living organisms
• List of organisms by chromosome count
• Lists of animals
• Lists of extinct animals
• Lists of mammals by population
  • World population (humans)
• List of birds by population
• Primary production
• Smallest organisms
• The world's 100 most threatened species
• Latitudinal gradients in species diversity

Notes and References

1. Web site: 2011 International Piping Plover Census: Study Description . 2012-12-24 . Forest and Rangeland Ecosystem Science Center . United States Geological Survey.
2. Web site: Positive Piping Plover Count . 2012-12-24 . 6 Nov 2006 . . dead . https://web.archive.org/web/20130506183411/http://www.environment.gov.sk.ca/Default.aspx?DN=73d2c0ca-c031-4ca5-81f4-5b5b9a2f3dc8 . 2013-05-06 .
3. Web site: Mountain plover survey guidelines — Wyoming . 2012-12-24 . March 2002 . . dead . https://web.archive.org/web/20130602134349/http://www.blm.gov/pgdata/etc/medialib/blm/wy/field-offices/newcastle/wildlife/docs.Par.53483.File.dat/SurveyProtocols.pdf . 2013-06-02 .
4. News: Christine . Dell'Amore . Emperor Penguins Counted From Space—A First . 13 April 2012 . . https://web.archive.org/web/20120415072425/http://news.nationalgeographic.com/news/2012/04/120413-emperor-penguins-survey-antarctica-animals-space-science/ . dead . April 15, 2012 . National Geographic News . 2012-12-22.
5. Book: Kunin, W.E. . Gaston, Kevin . The Biology of Rarity: Causes and consequences of rare—common differences . 31 December 1996 . Springer . 978-0412633805 . 26 May 2015 .
6. Book: Stearns . Beverly Peterson . Stearns . S. C. . Stearns . Stephen C. . Watching, from the Edge of Extinction . 2000 . . 978-0-300-08469-6. preface x . 30 May 2017 .
7. News: Novacek . Michael J. . Prehistory's Brilliant Future . 8 November 2014 . . 2014-12-25 .
8. Book: G. Miller. Scott Spoolman . Environmental Science - Biodiversity Is a Crucial Part of the Earth's Natural Capital . 2012 . . 978-1-133-70787-5 . 62 . 2014-12-27 .
9. Mora . C. . Tittensor . D.P. . Adl . S. . Simpson . A.G. . Worm . B. . How many species are there on Earth and in the ocean? . 23 August 2011 . . 10.1371/journal.pbio.1001127 . 21886479 . 3160336 . 9 . 8 . e1001127 . free .
10. Web site: State of observed species: A decade of species discovery in review . 2013-01-02 . Pennak, Sara . etal . 18 January 2012 . International Institute for Species Exploration; Arizona State University . dead . http://webarchive.nationalarchives.gov.uk/20121031181854/http%3A//timgostony.com/iisetemp/RetroSOS__FINAL.pdf . 31 October 2012 .
11. News: Staff . Researchers find that Earth may be home to 1 trillion species . 2 May 2016 . . 6 May 2016 .
12. News: Nuwer . Rachel . Rachel Nuwer . 18 July 2015 . Counting All the DNA on Earth . The New York Times . New York . 0362-4331 . 2015-07-18.
13. Web site: The Biosphere: Diversity of Life . . Aspen Global Change Institute . Basalt, CO . 2015-07-19 . 2014-11-10 . https://web.archive.org/web/20141110164609/http://www.agci.org/classroom/biosphere/index.php . dead .
14. News: Wade . Nicholas . Nicholas Wade . Meet Luca, the Ancestor of All Living Things . 25 July 2016 . . 25 July 2016 .
15. Whitman WB, Coleman DC, Wiebe WJ . Prokaryotes: the unseen majority . Proceedings of the National Academy of Sciences of the United States of America . 95 . 12 . 6578–6583 . June 1998 . 9618454 . 33863 . 10.1073/pnas.95.12.6578 . 1998PNAS...95.6578W . 16 September 2011 . 20 August 2008 . https://web.archive.org/web/20080820171651/http://www.pnas.org/cgi/reprint/95/12/6578.pdf . live . free .
16. Whitman . William B. . Coleman . David C. . Wiebe . William J. . Prokaryotes: The unseen majority . Proceedings of the National Academy of Sciences . 95 . 12 . 1998-06-09 . 0027-8424 . 10.1073/pnas.95.12.6578 . 6578–6583. 9618454 . 33863 . 1998PNAS...95.6578W . free .
17. Erin M. Eggleston . Ian Hewson . Ian Hewson . 2016 . Abundance of Two Pelagibacter ubique Bacteriophage Genotypes along a Latitudinal Transect in the North and South Atlantic Oceans . Frontiers in Microbiology . 7 . 1534 . 10.3389/fmicb.2016.01534 . 5039313 . 27733846 . free.
18. Web site: The Most Abundant Small Things Considered. Merry Youle. Gemma Reguera. amp. February 22, 2015.
19. Web site: Life in deep Earth totals 15 to 23 billion tons of carbon—hundreds of times more than humans . phys.org . en-us . 2018-12-30.
20. Web site: Number of chickens worldwide from 1990 to 2018 . Statista . 23 February 2020.
21. News: UN's Food and Agriculture Organisation . . Global Livestock Counts . July 2011 . July 13, 2017 . https://web.archive.org/web/20160715181213/http://www.economist.com/blogs/dailychart/2011/07/global-livestock-counts . July 15, 2016 . live .
22. http://factsanddetails.com/china.php?itemid=1052&catid=10&subcatid=68 Alligators, River Dolphins, Giant Salamanders In China - China | Facts And Details
23. Book: Trooper Walsh . Murphy, James Jerome . Claudio Ciofi . Colomba De LA Panouse . Komodo Dragons: Biology and Conservation (Zoo and Aquarium Biology and Conservation Series) . Smithsonian Books. Washington, D.C.. 2002. 1-58834-073-2.
24. Web site: . Ora (Komodo Island Monitor or Komodo Dragon) . 2007-01-15 . unfit . https://web.archive.org/web/20100307164050/http://www.amnh.org/nationalcenter/Endangered/ora/ora.html . March 7, 2010 .
25. Web site: Worrall . Simon . Without Bugs, We Might All Be Dead . https://web.archive.org/web/20170806113211/http://news.nationalgeographic.com/2017/08/insect-bug-medicine-food-macneal/ . dead . August 6, 2017 . 6 August 2017 . . 27 May 2018 .
26. Web site: "Numbers of Insects - Species and individuals" . . 23 Nov 2022.
27. Embery, Joan and Lucaire, Ed (1983) Collection of Amazing Animal Facts.
28. Web site: How many ants are on Earth? 20 quadrillion, study says . France 24 . September 19, 2022 . September 19, 2022.
29. News: Grandoni . Dino . How many ants are crawling the Earth? Nearly 20 quadrillion, scientists say. . Washington Post . September 19, 2022 . September 19, 2022.
30. Schultheiss P, Nooten SS, Wang R, Wong MKL, Brassard F, Guénard B. The abundance, biomass, and distribution of ants on Earth. . Proc Natl Acad Sci U S A . 2022 . 119 . 40 . e2201550119 . 36122199 . 10.1073/pnas.2201550119 . free . 9546634 . 2022PNAS..11901550S .
31. Web site: Going Out On A Limb With A Tree-Person Ratio : Krulwich Wonders... : NPR.
32. Ehrenberg . Rachel . Global count reaches 3 trillion trees - Approach combines ground-based surveys with satellite imaging to find higher density than anticipated. . 2 September 2015 . . 10.1038/nature.2015.18287 . 189415504 . 28 November 2015 .
33. Web site: How many tree species are there in the Amazon and how many of them will go extinct? . https://web.archive.org/web/20120326094239/http://www.pnas.org/content/105/suppl.1/11498.full . 26 March 2012.
34. Web site: Field Museum scientists estimate 16,000 tree species in the Amazon. EurekAlert!.