Purely H2O Forum

The worlds Coral reefs have formed through the mineral deposits of billions of small invertebrate animals, called coral polyps. All of these polyps survive via colonies, which are made up of one to many thousands of individuals. They are able to construct homes made from calcium carbonate, similar to the bones in our body. They can retract themselves into their little homes when attacked by predators. Over millions of years, these animals have been able to create vast underwater mountains which we call coral reefs. Coral polyps are similar to anemones, having tentacles, a mouth and an internal body sac called a gastrovascular cavity which is used to digest food. These polyps are sessile, meaning they cannot move; they catch prey with their tentacles, which may be floating on the water currents or swimming towards certain death. After having caught a prey, their cnidocytes release tiny poisonous harpoons. These powerful...