Science, Tech, Math › Animals & Nature Great Barrier Reef Pictures Share Flipboard Email Print Animals & Nature Habitat Profiles Amphibians Birds Mammals Reptiles Wildlife Conservation Insects Marine Life Forestry Dinosaurs Evolution View More By Laura Klappenbach Ecology Expert M.S., Applied Ecology, Indiana University Bloomington B.S., Biology and Chemistry, University of Illinois at Urbana-Champaign Laura Klappenbach, M.S., is a science writer specializing in ecology, biology, and wildlife. our editorial process Laura Klappenbach Updated March 08, 2017 01 of 12 Aerial View Aerial view of the Great Barrier Reef. Photo © Pniesen / iStockphoto. The Great Barrier Reef, a 2,300 kilometer long stretch of coral reefs that cradle the shores of northeastern Australia, is home to an astonishing diversity of animals including marine fish, hard corals, sponges, echinoderms, marine reptiles, marine mammals and a variety of seabirds and shorebirds. The Great Barrier Reef is the world's largest tropical reef system, covering an area of 348,000 km2 and stretching along 2300km of the eastern Australian coastline. 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. 02 of 12 Aerial View Aerial view of the Great Barrier Reef. Photo © Mevans / iStockphoto. The Great Barrier Reef is the world's largest tropical reef system, covering an area of 348,000 km2 and stretching along 2300km of the eastern Australian coastline. 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. 03 of 12 Christmas Tree Worm Christmas tree worm - Serpulidae. Photo © Stetner / iStockphoto. Christmas tree worms are small, tube-building polychaete worms that live in marine environments. Christmas tree worms are named after the colorful, spiral breathing structures they extend into the surrounding water which resemble tiny Christmas trees. 04 of 12 Maroon Clownfish Maroon clownfish - Premnas biaculeatus. Photo © Comstock / Getty Images. The maroon clownfish inhabits the Indian and Pacific Oceans. Their range stretches from western Indonesia to Taiwan and includes the Great Barrier Reef. The maroon clownfish has white or in some cases yellow stripes on their body. Female out-size males and are a darker shade of red. 05 of 12 Coral Coral - Anthozoa. Photo © KJA / iStockphoto. Corals are a group of colonial animals that form the structural framework of the reef. Corals provide habitat and shelter for many other reef-dwelling creatures. Corals form mounds, branches, shelves and tree-like structures that give the reef its dimension. 06 of 12 Butterflyfish and Angelfish Butterflyfish and angelfish - Chaetodon and Pygoplites. Photo © Jeff Hunter / Getty Images. A gathering of butterflyfish and angelfish swim around a staghorn coral at the Great Barrier Reef. The species include the Pacific double-saddle Butterflyfish, black-backed butterflyfish, blue-spot butterflyfish, dot & dash butterflyfish, and a regal angelfish. 07 of 12 Diversity and Evolution Photo © Hiroshi Sato The Great Barrier Reef is among the most complex ecosystems on the planet, providing habitat for a stunning variety and number of species: 1500 species of marine fish360 species of hard corals600 species of echinoderms (starfish, sea urchins, sea cucumbers)500 species of seaweed400 species of spongesa variety of marine mammals (whales, dolphins, dugongs)6 species of marine turtles200 species of birds125 species of sharks The species diversity and complex interactions that characterize the wildlife of the Great Barrier Reef reflect a mature ecosystem. The evolution of the Great Barrier Reef began after Australia broke away from the Gondwana land mass 65 million years ago. Australia drifted northward to warmer tropical waters—waters that could support the formation of coral reefs. By 18 million years ago, it is thought that the northern parts of the Great Barrier Reef started to form, spreading gradually southward. 08 of 12 Sponges and Echinoderms Photo © Fred Kamphues Sponges belong to the Phylum Porifera. Sponges occur in almost every type of aquatic habitats but are most common in the marine habitats. The Phylumn Porifera is further broken down into three classes, Class Calcarea, Class Demospongiae, and Class Hexactinellida. Sponges have a unique method of feeding in that they do not posess mouths. Instead tiny pores located in the outer walls of the sponge draw water into the animal and food is filtered out of the water as it is pumped through the body and discarded through larger openings. Water flows in one direction through the sponge, driven by flagella that line the surface of the sponge's feeding system. Some sponges that occur in the Great Barrier Reef include: yellow burrowing spongetubular spongethick yellow fan sponge Echinoderms belong to the Phylum Echinodermata. Echinoderms are pentaradially (five-axis) symmetrical as adults, have a water-vascular system, and an endoskeleton. Members of this phylum include sea stars, sea urchins, sea cucumbers, and sea lilies. Some echinoderms that occur in the Great Barrier Reef include: sea urchinsea cucumberblue sea starbrittle star 09 of 12 Marine Fish Blue-Green Chromis - Chromis viridis. Photo © Comstock / Getty Images. Well over one thousand species of fish inhabit the Great Barrier Reef. They include: yellow-faced angelfishesfirefishfusiliersblue tuskfishescardinal fishestervalliesgobiesMandarin fishesmanta raystiger sharkswhale sharks 10 of 12 Anemonefish Photo © Marianne Bones Anemonefish are a unique group of fish that live amongst the tentacles of sea anemones. The anemone's tentacles sting and paralyze most fish that brush against them. Fortunately, anemonefishes have a layer of mucus covering their skin that prevents the anemones from stinging them. By seeking shelter amongst the sea anemone's tentacles, the anemone fish are protected from other predatory fish that might otherwise see the anemonefish as a meal. Anemonefish are never found far from the protection of their host anemone. Scientists believe the anemonefish provide benefits to the anemones as well. The anemonefish drops scraps of food as it eats and the anemone cleans up the left overs. Anemonefishes are also territorial and drive off butterflyfish and other anemone-eating fishes. 11 of 12 Feather Stars Photo © Asther Lau Choon Siew Feather stars are echinoderms, a group of animals that includes sea urchins, sea cucumber, sea stars, and brittle stars. Feather stars have numerous feathery arms that radiate out from a small body. Their mouth is located on the top of their body. Feather stars use a feeding technique called passive suspension feeding in which they extend their feeding arms into the current of the water and catch food as it filters through. Feather stars can range in color from bright yellow to red. They are usually active at night and during the day they seek shelter under coral ledges and in the dark crevices of underwater caves. As darkness descends upon the reef, the feather stars migrate onto reef where they extend their arms into the water currents. As water flows through their extended arms, food becomes trapped in their tube feet. 12 of 12 Recommended Reading A Visual Guide to the Great Barrier Reef. Photo © Russell Swain Recommended Reading If you would like to learn more about the Great Barrier Reef, I would highly recommend Reader's Digest Guide to the Great Barrier Reef. It has a wonderful collection of photographs and is packed with facts and information about the animals and wildlife of the Great Barrier Reef.