Millions of polyps grow on top of the limestone remains of former colonies to create the massive reefs. Yet these tiny microscopic animals form the only natural formation visible from outer space. Another symbiotic realtionship on the coral reef is the clown fish and the sea anemone. Symbiosis on the Coral Reef A coral reef is the largest and most spectacular structure made by living things. This relationship is an example of symbiosis - the intimate living together of two or more dissimilar organisms where at least one of the organisms is benefited.
Reefs are useful to the environment and to people in a number of ways.
However, all around the world, much of the world's marine biodiversity face threats from human and activities as well as natural. It is feared that very soon, many reefs could die off. Biodiversity actually boosts ecosystem productivity where each species, no matter how small, all have an important role to play and that it is this combination that enables the ecosystem to possess the ability to prevent and recover from a variety of disasters. This is obviously useful for mankind as a larger number of species of plants means more variety of crops and a larger number of species of animals ensure that the ecosystem is naturally sustained. It is feared that human activity is causing massive extinctions.