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The largest organism found on Earth can be measured using a variety of different methods. It could be defined as the largest by volume, mass, height, or length. Some creatures group together to form a superorganism, though this cannot truly be classed as one large organism and is usually only common amongst invertebrates.
There are many difficulties in truly defining the largest organism. A giant fungus of the species Armillaria ostoyae in the Malheur National Forest was found to span 8.9 km² (2200 acres). Whether or not this is an actual individual organism is disputed: some tests have indicated that they have the same genetic makeup , but this does not exclude its being a clonal colony of numerous smaller individuals. The Aspen tree, (Populus tremuloides), also forms large clonal colonies of genetically identical trees (technically, stems) connected by a single underground root system. These trees form through root sprouts coming off an original parent tree, though the root system may not remain a single unit in all specimens. One such grove covers 80 hectares and is estimated to weigh 6600 tons The largest fully-connected Aspen is Pando, and some experts call it the world's largest[http://www.olis.oecd.org/olis/2000doc.nsf/4f7adc214b91a685c12569fa005d0ee7/c125692700623b74c1256a0600551816/$FILE/JT00103743.DOC Consensus Document on the Biology of Populus, OECD (.doc file) and oldest organismQuaking Aspen by the Bryce Canyon National Park Service.
Excluding possible clonal colonies, the General Sherman tree, an individual Giant Sequoia with a volume of 1489 m3, would hold the title of the world's largest tree (by volume of its trunk). The Great Barrier Reef, the world's largest coral reef stretching 2000 km, has been shown to be a collection of many organisms and is the largest living superorganism, though the whole of the biosphere in some respects can be considered as a superorganism (see Gaia theory).
By volume and weight, the largest known animal ever to have lived is the blue whale, an endangered species that can measure 30 m (100 feet) in length and can weigh in excess of 200 tons. There is currently no conclusive evidence that a larger animal has ever existed. The largest land animals today are male Savannah Elephants, with one known example weighing around 12,000 kg (26,400 pounds), though many extinct species, such as many dinosaurs, were much larger.
Living animals
Mammals (Mammalia)
The Blue whale (Balaenoptera musculus) is believed to be the largest animal ever to have lived, with lengths of up to 30 m (100 feet) and weights in excess of 200 tons. The Savannah Elephant (Loxodonta africana) is the largest living land mammal. At birth it is common for an elephant calf to weigh 100 kg (225 pounds). The largest elephant ever recorded was shot in Angola in 1974. It was a male and weighed 12,000 kg (26,400 pounds - over 13 tons).Monotremes (Monotremata)
The largest monotreme (egg-bearing mammal) ever was the extinct echidna species Zaglossus hacketti, known only from a few bones found in western Australia.Placentals (Placentalia)
By order:- Colugos (Dermoptera). Of the two colugo species in the order Dermoptera of gliding arboreal mammals in southeast Asia, the largest and most common is the Malayan colugo (Cynocephalus varigatus)
- Elephants, mammoths, and mastodons (Proboscidea). Contrary to popular belief, extinct species in the order Proboscidea (such as mammoths and mastodons) are not larger than today's elephants. The Savannah Elephant is the largest living elephant, and is believed to be the largest known species ever in Proboscidea.
- Bats (Chiroptera). The largest bat is the giant golden-crowned flying fox, a rare fruit bat and endangered species that is part of the megabat family.
- Scaly anteaters (Pangolin). The largest species of scaly anteaters is the Giant Pangolin.
- Rodents (Rodentia). The largest living rodent is the capybara, native to most of the tropical and temperate parts of South America east of the Andes, always near water. Full-grown capybaras reach between 105 and 135 cm in length, and weigh 35 to 65 kg. The largest known rodent ever is Phoberomys pattersoni, an extinct rodent who lived in the Orinoco River delta about 8 million years ago. An almost complete skeleton of the giant rodent was discovered in Venezuela in 2000; it was 3 m long, with an additional 1.5 m tail, and probably weighed around 700 kg.
- Primates. The Eastern Lowland Gorilla (Gorilla beringei graueri) subspecies is the largest living primate; males weigh about 180 kg (400 pounds) in the wild and can be much heavier in captivity. Gigantopithecus is the largest known primate, probably 3 m (10 ft) tall and weighing 300 to 550 kg (700 to 1200 lb). It lived 1 to 5 million years ago in the region of India and China. Human beings, homo sapiens sapiens, can attain massive weights measured in thousands of pounds, but these are cases of morbid obesity, tumor, and other medical malady.
- Dugongs and manatees (Sirenia). The largest living species in the order Sirenia of dugongs and manatees is the West African manatee; however, the extinct Steller's Sea Cow (Hydrodamalis gigas) was much larger, growing up to 7.9 m long and weighing up to 11 tonnes.
Birds
The largest living bird is the ostrich (Struthio camelus), reaching a height of up to 2.5 m (8 feet). Eggs laid by the Ostrich can weigh 1.3 kg and are the largest eggs in the world today (and are also the largest single cell of any organism). The largest flightless bird known is the Elephant bird.The largest birds believed to be capable of flight are the now extinct members of the Teratornithidae group, with some found with wingspans of 7 meters. The largest contemporary bird capable of flight is the great albatross, with a wingspan of about 3,50 m (12 ft).
Reptiles
The largest living reptile is the saltwater crocodile (Crocodylus porosus), with adult males being typically 4.5–5 m long, although the largest recorded crocodile was 8.63 m (28.3 feet) in length and weighed over 2000 kg (4400 pounds)*. Average-sized males weigh around 450 kg. Females are much smaller than males, with typical female body lengths in the range of 2.5–3 m. Extinct crocodilians, such as Deinosuchus, could grow to as much as twice this size.Fish
The largest living fish is the whale shark, recorded to be up to 12 m long, with unofficial accounts of 18 m.Cnidaria
The lion's mane jellyfish is the largest cnidaria (jellyfish) species, with some attaining a bell diameter of 2.5 m (8 feet) and tentacles as long as 30 m (100 feet) or more.Invertebrates
The largest undisputed invertebrate is the giant squid measuring up to 13 m (43 ft) or more from tip to tip. Interestingly it also has the second largest eyes for any animal in the world measuring 50 cm (20 in). However, the adult colossal squid (which is known from juvenile specimens) may considerably exceed it in mass, if not in length.Crustaceans
The American lobster is the largest marine crustacean in the world, weighing up to 20 kg and reaching 60 cm in length. In terms of the length, the Japanese spider crab at almost 4 m leg span (13 feet) is the longest crustacean.Extinct animals
Some of the largest animals ever to have existed have now died out. Most of them dinosaurs, the creatures grew to enormous sizes. The evidence of their size is shown by their fossilised remains, with the entire skeletons of many species being discovered and reconstructed.Complete skeletons
The tallest and heaviest dinosaur known from a complete skeleton is the Brachiosaurus (now Giraffatitan) which was discovered in Tanzania between 1907–1912, and is now mounted in the Humboldt Museum of Berlin. It is 12 m (38 ft) tall, and probably weighed between 30,000–60,000 kg (30–65 tons). The longest is the 27 m (89 ft) long Diplodocus which was discovered in Wyoming, and mounted in Pittsburgh's Carnegie Natural History Museum in 1907.Incomplete skeletons
There are bigger dinosaurs, but they are known from only a small handful of bones. The current record holders all date from the 1970s or later, and include the massive Argentinosaurus, which may have weighed 80,000–100,000 kg (90–110 tons); the longest, the 40 m (130 ft) long Supersaurus; and the tallest, the 18 m (60 ft) Sauroposeidon, which could have reached into a 6th-floor window. Seismosaurus was once thought to have measured around 50 m (140 ft) in length, making it the longest known animal, but more recent reconstructions have dropped this figure significantly — down to 110 ft.Less well described finds may even exceed this. Bruhathkayosaurus, may have weighed as much as a blue whale and have been considerably longer, and the almost mythical Amphicoelias fragillimus would have been bigger still, but Bruhathkayosaurus is based on very poor material, and Amphicoelias's only fossil was destroyed soon after discovery.
Other groups
The largest flightless bird found through fossil evidence is the Dromornis stirtoni, measuring three metres tall and weighing half a tonne. Marine euryapsid reptiles (often mistakenly referred to as marine dinosaurs) outsized many present-day whales. The Leedsichthys, from the Jurassic period (165–155 million years ago), is thought to have been the largest fish to have ever lived, with estimates of some growing to 20–22 m (66–72 feet) in length. The Megalodon, a relative of the great white shark, is thought to have been the largest carnivorous fish. Flying reptiles known as pterosaurs are known to have reached a wingspan of 14 meters and believed to have grown as big as 18 meters (60 feet) *.
Plants
The largest tree by circumference is the Árbol del Tule, a Montezuma Cypress (Taxodium mucronatum) in Mexico, having a circumference of 35.87 m (diameter of 11.42 m) (37.5 ft) at 1.5 m above ground level.The largest tree by volume and mass is the Giant Sequoia (Sequoiadendron giganteum). They grow to an average height of 70–85 m (230–280 ft) and 5–7 m (16–23 ft) in diameter. Specimens have been reported to be 93.6 m (307 ft) in height and (not the same individual) 8.85 m (29 ft) in diameter; the largest individual is the General Sherman tree, with a volume of 1489 m³. Although not so large in volume, the closely related Coast Redwood (Sequoia sempervirens) is taller, reaching a maximum height of 112.83 m. See record trees for other tree records.
The Giant Sequoia is a conifer, as are the next four or five largest plant species. The largest flowering plant (angiosperm) is Eucalyptus regnans which can reach heights of 92 m *. The largest flower belongs to the species Rafflesia arnoldii, with a diameter of nearly a meter and a weight up to 11 kg. The largest unbranched inflorescence, resembling one giant flower, belongs to the Titan arum.
There are arguments that forests of trees with interconnected roots (a single organism genetically) are actually the largest organisms.
A giant marine plant, Posidonia oceanica, has been discovered in the Mediterranean Sea near the Balearic Islands, Spain. Its length is about 8 km. Although it is not proved if it is a single organism, all the samples have the same DNA. It is also thought to be the oldest living organism in the world since its estimated age is about 100,000 years.
Other kingdoms
The largest fungus may be a honey fungus of the species Armillaria ostoyae. One genetically constant mycelium has been found over an area of more than 8.9 km² (3.4 square miles), though it is unlikely that it is a true single organism with all parts of the mycelium connected.The largest protists are kelp, which are multicellular algae that may grow past 30 metres in length. Of the groups that are not multicellular, the largest are the slime moulds, some of which cover more than 1000 square centimetres. The largest species traditionally considered protozoa are giant amoeboids like foraminiferans, a few centimetres in size.
The largest bacterium ever discovered is Thiomargarita namibiensis, which grows to 0.75 mm in diameter, making it visible to the naked eye and up to a million times the size of more typical bacteria. The largest known virus is the mimivirus, with mature particles of 400 nm in diameter (icosahedral capsid), 800,000 bases and 900 genes. Later research suggested that it could be up to 800 nm long, 1.2 Mbp and 1260 genes.
See also
Notes
References
- The General Sherman Tree, Sequoia National Park at the National Park Service. Accessed 20 August 2005.
- The Humongous Fungus--Ten Years Later at the University of Wisconsin, Department of Botany. Accessed 20 August 2005.
- Beale, Bob. 10 April 2003. Humungous fungus: world's largest organism? at Environment & Nature News, ABC Online. Accessed 20 August 2005.
"Largest organism"