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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 insects.

There are many difficulties in truly defining the largest organism. The General Sherman tree, an individual Giant Sequoia with a volume of 1489 m³, is generally considered to hold the title^[1]. However, the Malheur National Forest Armillaria ostoyae (a species of honey fungus) was found to span 8.9 km² (2200 acres)^[2]. Whether or not this is an actual individual organism is disputed – the likelihood of all parts of the mycelium (the vegetative part of fungi) being connected is very small, though some tests have indicated that they have the same genetic makeup ^[3]. The Aspen tree, (Populus tremuloides), also forms large stands of genetically identical trees. These trees form through runners coming off an original parent tree. All remain connected through their roots and could therefore be considered one organism. One such grove covers 200 acres and is estimated to weigh 6600 tons[4]. 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.

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 up to 140 tonnes (150 short tons) or more. There is currently no conclusive evidence that a larger animal has ever existed, but the phenomenon known as "Bloop" might indicate otherwise. 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 dinosaurs, were much larger.

Contents [hide] 1 Living animals 1.1 Mammals (Mammalia) 1.1.1 Monotremes (Monotremata) 1.1.2 Placentals (Placentalia) 1.2 Birds 1.3 Reptiles 1.4 Fish 1.5 Cnidaria 1.6 Invertebrates 1.7 Crustaceans 2 Extinct animals 2.1 Complete skeletons 2.2 Incomplete skeletons 2.3 Other groups 3 Plants 4 Other kingdoms 5 See also 6 References

 

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 of up to 140 tonnes (150 short tons) or more. 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).

 

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.
• 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).

 

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 6.3 m (20.7 feet) in length and weighed over 1000 kg (2200 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 Phobosucchus, 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. This makes it the longest living animal.

 

Invertebrates

The largest undisputed invertebrate is the giant squid measuring up to 43 feet or more from tip to tip. Interestingly it also has the 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 (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 a mere 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). [5]

 

Plants

The Giant Sequoia (Sequoiadendron giganteum) is the world's largest tree in terms of total volume. 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 [6]. The largest flower belongs to the species Rafflesia arnoldii, with a diameter of nearly a meter and a weight up to 11 kg.

 

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

• Deep-sea gigantism

 

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.