What is a coral polyp?

Coral polyps are a general term for many kinds of organisms in the class Corals, with a cylindrical body with eight or more tentacles and a mouth in the center of the tentacles. Gregarious, combined into a group, is a marine cylindrical coelenterate in which food enters through the mouth and food residue is excreted from the mouth. It preys on tiny plankton in the ocean and absorbs calcium and carbon dioxide from the sea during its growth. and then secrete limestone into their own living shell. Coral is the secretion of coral polyps and forms the supporting structure of coral polyps.

Corals are tiny and have many small tentacles around their mouth, which are used to capture tiny creatures in the ocean. Can absorb minerals from sea water to build a shell to protect the body. Coral polyps are only polyp-shaped individuals, hollow cylindrical, attached to the surface of the object at the lower end, with a mouth at the top and surrounded by one or more tentacles. Tentacles are used to collect food and can be stretched to a certain extent with specialized cells (stinging cells). When stimulated, the stinging cells turn out of the barbed sac to paralyze the prey.

Coral polyps generally live in groups, and each individual is connected to each other by a structure called common meat, which can secrete horny or calcareous exoskeletons. The tentacles of coral polyps are very small and grow on the edge of the mouth. When the sea water passes through the digestive cavity, the food and calcium are absorbed by it. Coral polyps live with algae, which live on waste from coral polyps and provide oxygen to coral polyps. Algae need sunshine and a warm environment to survive. The higher the coral accumulation, the more conducive to the survival of algae.

Coral polyps multiply rapidly in the tropics, grow fast, the old ones continue to die, the new ones continue to grow, and their bones grow and expand, accumulating sand into towers that grow into huge coral reefs and islands over a long period of time. Dongsha Islands and Paracel Islands in the South China Sea, Maldives Island in the Indian Ocean, Fiji Island in the South Pacific and the world-famous Great Barrier Reef are all built by small coral polyps.

The eggs and sperm of coral polyps are produced by the gonads on the septum and discharged into the sea through the mouth. Fertilization usually occurs in sea water and sometimes in the gastric circulatory cavity. Fertilization usually occurs only between eggs and sperm from different individuals. The fertilized egg develops into a floating larva covered with cilia and can swim. After a few days to weeks, they fixed on the fixed surface and developed into polyps. Coral polyps can also reproduce in the way of budding. after bud formation, new buds are not separated from the original polyps, and new buds continue to form and grow, thus forming groups. When the new polyps grow and develop, the old polyps die, but their bones remain in the population.