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The Largest Organisms on Earth

A Guide to the Largest Living Organisms on the Planet

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Giant sequoias, blue whales, Komodo dragons, African elephants all share the distinction of being among the world's largest organisms. Find out more about these and other sizeable creatures in this article examining the largest organisms on Earth.

Largest Coral Reef - The Great Barrier Reef

Princess Charlotte Bay is a part of the Great Barrier Reef Marine Park.
Photo courtesy NASA.
The Great Barrier Reef is the world's largest tropical reef system and the largest structure on the planet that is made up of living organisms. The Great Barrier Reef covers an area of 348,000 km2 and stretching along 2300 km of the eastern Australian coastline and is visible from space. The Great Barrier Reef is made up of over 200 individual reefs and 540 inshore islands (many with fringing reefs). It is among the most complex ecosystems on the planet. The Great Barrier Reef is made up of billions of coral polyps.

Largest Tree - Giant Sequoia (Sequoiadendron giganteum)

Photo © Peciva / iStockphoto.
Giant sequoias (Sequoiadendron giganteum) are reputed to be the world's largest trees in terms of volume. Giant sequoias can grow to heights of 50–85 m 9165–280 ft) and can attain diameters of 6–8 m (18–24 ft). The native range of the giant sequoia is restricted to the western Sierra Nevada in California. They grow at elevations of 900-2700 m in habitats of mixed montane coniferous forests. Giant sequoias are one of three redwood species, the others being the dawn redwood (Metasequoia glyptostroboides) and the coast redwood (Sequoia sempervirens).

Largest Tree Root System - Aspen (Populus tremuloides)

Photo © Adventure Photo / iStockphoto.
Genetically identical aspen trees (Populus tremuloides) grow in large stands throughout cooler regions of North America. The individual trees within these stands are interconnected by a shared root system and it is that root system that ranks as the largest on the planet. New aspen trees grow as root sprouts that grow off of a parent tree. The largest known aspen grove, nicknamed Pando, is located in Utah and covers 106 acres and is estimated to weigh 6000 tonnes.

Largest Animal - Blue Whale (Balaenoptera musculus)

Public Domain Photo / NOAA.
The blue whale (Balaenoptera musculus) is the largest member of the order Cetacea and the largest animal alive today. It is possibly the largest animal ever to have lived. Blue whales produce vocalizations at volumes in excess of 180 decibels and are therefore also the loudest animal on the planet. Blue whales weigh between 110–160 tonnes (110—176 tons) and mature individuals measure in the range of 20–30 m (66–98 ft). The fin whale (Balaenoptera physalus) comes in a close second in size to the blue whale, weighing 47–74 tonnes (50–82 tons) and measuring 19–22 m (62–72 ft).

Largest Lizard - Komodo Dragon (Varanus komodoensis)

Photo © Dennis Hinaris / iStockphoto.
Komodo dragons (Varanus komodoensis) are the largest of all lizards, they can grow to lengths of 3m and can weigh as much as 165kg. Komodo dragons belong to the Family Varanidae, a group of reptiles known more commonly as the monitor lizards. Adult Komodo dragons are dull brown, dark grey, or reddish in color, while juveniles are green with yellow and black stripes. Komodo dragons are carnivores and scavengers. They are the top carnivores in their ecosystems.

Largest Land Animal - African Elephant (Loxodonta africana)

Photo © Lynn Amaral / Shutterstock.
The African elephant (Loxodonta africana) is the largest of the proboscids (order Proboscidae) and in turn, the largest land animal on Earth. African elephants weigh in the range of 4–7 tonnes (4.5–7.8 tons) and are 4—5 m (13—16 ft) in length. The African elephant is one of only two species of elephants alive today, the other species is the smaller Asian elephant (Elephas maximus) which inhabits southeast Asia. The African elephant has larger ears than the Asian elephant.

Tallest Land Animal - Giraffe (Giraffa camelopardalis)

Photo © Heather Barr / Shutterstock.
Giraffes (Giraffa camelopardalis) are the tallest of all living land animals. They can be as tall as 5.8 m (19 ft). Giraffes are hoofed mammals with long legs and a long neck. Their skin is a patchwork of dark chestnut spots separated by thin cream colored lines. Their coloration varies slightly, with various subspecies having less disinct spots or spots that can vary from a yellowish color to black. Giraffes are well-adapted to graze leaves and fruit from the branches of trees. Their elongated tounge and long neck enable them to extend up to 18 feet when reaching upward among vegetation.

Largest Fungus - Honey Mushrooms (Armillaria ostoyae)

Photo © WJ Pilsak / Wikipedia.
Honey mushrooms (Armillaria ostoyae) rank among the largest organisms on earth when measured by the area they cover. A single honey mushroom colony in Malheur National Forest in Oregon covers an area of 8.9 km2 (2200 acres). Honey mushrooms belong to a genus of parasitic fungi that grow on trees and woody shrubs. The cap of a honey mushroom is 3–15 cm in diameter and is a honey-brown color and is covered with small, darker-colored scales. Some species related to honey mushrooms are bioluminescent. The glow they produce is thought to be responsible for the phenomenon known as foxfire.

Largest Flower - Rafflesia arnoldii

Photo © Masuska / Wikipedia.
Rafflesia arnoldii is rare parasitic vascular plant that produces the largest individual flower on the planet. The flower of Rafflesia arnoldii can reach close to 1 m (3 ft) in diameter and can weigh as much as 11 kg (24 lb). Rafflesia arnoldii is native to the tropical rainforests of Sumatra and Borneo in the Malay Archipelago. Rafflesia arnoldii has no roots, stems, or leaves so it depends on the host plant for nutrients. It does not have chlorophyll so it is unable to photosynthesize and produce its own food.

Largest Invertebrate - Colossal Squid (Mesonychoteuthis hamiltoni)

Photo © New Zealand Ministry of Fisheries / Getty Images.
The Colossal Squid (Mesonychoteuthis hamiltoni) is the world's largest squid species and the largest invertebrate on Earth. Colossal squids measure in the range of 12–14 m (39–46 ft). The colossal squid's range is believed to be circumantarctic around the Southern Oceans, extending northward from the icy waters off the coast of Antarctica to South America, southern South Africa, and the southern tip of New Zealand. The largest known specimen of colossal squid was captured in 2007 in New Zealand. That individual weighted 495 kg (1091 lb) and measured 10 m (33 ft) in length.
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