Diversity
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 fish
- 360 species of hard corals
- 600 species of echinoderms (starfish, sea urchins, sea cucumbers)
- 500 species of seaweed
- 400 species of sponges
- a variety of marine mammals (whales, dolphins, dugongs)
- 6 species of marine turtles
- 200 species of birds
- 125 species of sharks
Evolution of the Reef
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.
Sources
For a list of sources used in the creation of this visual guide, please see the Recommended Reading page.