GEOLOGY

Detailed explanation-1: -Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian.

Detailed explanation-2: -Appearing as solitary forms in the fossil record more than 400 million years ago, corals are extremely ancient animals that evolved into modern reef-building forms over the last 25 million years. Coral reefs are unique (e.g., the largest structures on earth of biological origin) and complex systems.

Detailed explanation-3: -Encrusting corals grow as a thin layer against a substrate. Massive corals are ball-shaped or boulder-like and may be as small as an egg or as large as a house. Mushroom corals resemble the unattached tops of mushrooms. In general, massive corals tend to grow slowly, increasing in size from 0.5 cm to 2 cm per year.

Detailed explanation-4: -The oldest known corals lived during the Cambrian, more than 500 million years ago, and are still found living today.

Detailed explanation-5: -The Aboriginal Australians knew about the Great Barrier Reef before the first European explorers and they have been living in that region for 40, 000 years. Its first recorded discovery was by the French explorer Louis de Bougainville in 1768 and in 1770 the British Captain James Cook accidentally ran his ship into it.