Largest organisms

File:FallPando02.jpg

Although it appears to be multiple trees, Pando is a clonal colony of an individual quaking aspen with an interconnected root system. It is widely held to be the world's most massive single organism.

This article lists the largest organisms for various types of life and mostly considers extant species,Template:Efn which found on Earth can be determined according to various aspects of an organism's size, such as: mass, volume, area, length, height, or even genome size. Some organisms group together to form a superorganism (such as ants or bees), but such are not classed as single large organisms. The Great Barrier Reef is the world's largest structure composed of living entities, stretching but contains many organisms of many types of species.

When considering singular entities, the largest organisms are clonal colonies which can spread over large areas. Pando, a clonal colony of the quaking aspen tree, is widely considered to be the largest such organism by mass. Even if such colonies are excluded, trees retain their dominance of this listing, with the giant sequoia being the most massive tree. In 2006, a huge clonal colony of the seagrass Posidonia oceanica was discovered south of the island of Ibiza. At across, and estimated at 100,000 years old, it may be one of the largest and oldest clonal colonies on Earth.

Among animals, all of the largest species are marine mammals, specifically whales. The blue whale is believed to be the largest animal to have ever lived. The living land animal classification is also dominated by mammals, with the African bush elephant being the largest of these.

Plants

The largest single-stem tree by wood volume and mass is the giant sequoia (Sequoiadendron giganteum), native to California's Sierra Nevada; it typically grows to a height of and in diameter.

The largest organism in the world, according to mass, is the aspen tree whose colonies of clones can grow up to in size. The largest such colony is Pando, in the Fishlake National Forest in Utah.

A form of flowering plant that far exceeds Pando as the largest organism on Earth in area and potentially also mass, is the giant marine plant, Posidonia australis, living in Shark Bay, Australia. Its length is about and it covers an area of . It is also among the oldest known clonal plants.

Another giant marine plant of the genus Posidonia, Posidonia oceanica discovered in the Mediterranean near the Balearic Islands, Spain may be the oldest living organism in the world, with an estimated age of 100,000 years.

The largest individual flower in the world is Rafflesia arnoldii, while the flowering plant with the largest unbranched inflorescence in the world is Amorphophallus titanum. Both are native to Sumatra in Indonesia.

Green algae

Green algae are photosynthetic unicellular and multicellular "green plants" that are related to land plants. The thallus of the unicellular mermaid's wineglass, Acetabularia, can grow to several inches (perhaps 0.1 to 0.2 m) in length. The fronds of the similarly unicellular, and invasive Caulerpa taxifolia can grow up to a foot (0.3 m) long.

Animals

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The blue whale is the largest animal alive today.

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Bruhathkayosaurus is potentially the largest animal to have walked the earth.

Fungi

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Armillaria ostoyae

The largest living fungus may be a honey fungus of the species Armillaria ostoyae. A mushroom of this type in the Malheur National Forest in the Blue Mountains of eastern Oregon, U.S. was found to be the largest fungal colony in the world, spanning of area and possibly weighing as much as 35,000 tons. This organism is estimated to be 2,400 years old. The fungus was written about in the April 2003 issue of the Canadian Journal of Forest Research. It is not known, however, whether it is a single organism with all parts of the mycelium connected.

A spatial genetic analysis estimated that a specimen of Armillaria ostoyae growing over in northern Michigan, United States weighs 440 tons (4 x 10⁵ kg).

In Armillaria ostoyae, each individual mushroom (the fruiting body, similar to a flower on a plant) has only a stipe, and a pileus up to across. There are many other fungi which produce a larger individual size mushroom. The largest known fruiting body of a fungus is a specimen of Phellinus ellipsoideus (formerly Fomitiporia ellipsoidea) found on Hainan Island. The fruiting body masses up to .

Until P. ellipsoideus replaced it, the largest individual fruit body came from Rigidoporus ulmarius. R. ulmarius can grow up to , tall, across, and has a circumference of up to .

Lichen

Umbilicaria mammulata is among the largest lichens in the world. The thallus of U. mammulata is usually in diameter, but specimens have been known to reach in the Smoky Mountains of Tennessee.

The longest lichen is Usnea longissima, which may grow to exceed in length.

Protists

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Macrocystis pyrifera, the largest species of giant kelp

(Note: the group Protista is not used in current taxonomy.)

Amoebozoans (Amoebozoa)

Among the organisms that are not multicellular, the largest are the slime molds, such as Physarum polycephalum, some of which can reach a diameter over . These organisms are unicellular, but they are multinucleate.

Euglenozoans (Euglenozoa)

Some euglenophytes, such as certain species of Euglena, reach lengths of 400 μm.

Rhizarians (Rhizaria)

The largest species traditionally considered protozoa are giant amoeboids like foraminiferans. One such species, the xenophyophore Syringammina fragilissima, can attain a size of .

Alveolates (Alveolata)

The largest ciliates, such as Spirostomum, can attain a length over .

Stramenopiles (Stramenopila)

The largest stramenopiles are giant kelp from the northwestern Pacific. The floating stem of Macrocystis pyrifera can grow to a height of over .

Macrocystis also qualifies as the largest brown alga, the largest chromist, and the largest protist generally.

Heliozoa

As of 2021Template:Dated maintenance category (articles), the largest known heliozoan is Berkeleyaesol magnus (formerly Raphidiophrys magna): its axopodial sphere can reach a diameter up to 6350 μm, with a cell body diameter of 1486 μm, a mucilaginous envelope 540 μm thick, and up to 1892 μm long axopodia.

Bacteria

The largest known species of bacterium is named Thiomargarita magnifica, which grows to in length, making it visible to the naked eye and also about five thousand times the size of more typical bacteria. BBC News described it as possessing the "size and shape of a human eyelash." Science published a new paper on the bacterium on June 23, 2022. According to a study coauthored by Jean-Marie Volland, a marine biologist and scientist at California's Laboratory for Research in Complex Systems, and an affiliate at the US Department of Energy Joint Genome Institute, T. magnifica can grow up to 2 centimeters long.

• Cyanobacteria

One of the largest "blue green algae" is Lyngbya, whose filamentous cells can be 50 μm wide.

Viruses

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A collection of viruses along with the bacterium E. coli, including M. horridgei - the largest virus

The largest virus on record is Megaklothovirus horridgei, with the length of 4 micrometres, comparable to the typical size of a bacterium and large enough to be seen in light microscopes. It was discovered in 2018 (being mistaken for bristles beforehand), having been found on an arrow worm in the genus Spadella. Prior to this discovery, the largest virus was the peculiar virus genus Pandoravirus, which have a size of approximately 1 micrometer and whose genome contains 1,900,000 to 2,500,000 base pairs of DNA.

Pandoravirus infects amoebas specifically, however Megaklothovirus infects Spadella arrow worms.

See also

• Charismatic megafauna
• Deep-sea gigantism
• Genome size
• Island gigantism
• Largest body part
• Largest prehistoric animals
• List of longest-living organisms
• List of heaviest land mammals
• List of world records held by plants
• List of largest inflorescences
• Lists of organisms by population
• Megafauna
• Smallest organisms
• Superorganism

External links

• 10 of the largest living things on the planet Melissa Breyer. TreeHugger April 28, 2015