The formation of coral reef
The coral which is under sea , in the sunlight , is red ,yellow or blue, it is colorful .The shape looks like the branch, the human brain, the wicker, the flowers and so on in a thousand pictures, it is fascinating.
Coral looks like plant, actually it is a low-level sea animal. A coral reef is often tens of thousands of 100 million coral groups. The live coral in the sea is colorful, yellow, green, purple, red, the color is bright and pleasant, it is called seabed flower. The white coral we often see, is the wreckage and bone of the death coral. Corals are very small, only can be seen through the microscope.
Corals have no eyes, nose, they only have sensitive tentacles that are the sensory organs. The tentacles drift with the current slowly, stretching freely to capture plankton and debris which is in the vicinity of their body. When they are frightened, they will retract their hands instantly. In the central of the tentacles, there is a small mouth, it is the mouth of the coral , called "stomodaeum." into the stomodaeum is the rectum,which has no the esophagus and stomach. The residue that has digested, will be disgorged from the stomodaeum again, the anus can’t distinguish from the mouth, and therefore they are calledas low-level sea animal.
A tiny coral insect reproduces offspring neither as hens hatch chicks by laying eggs, nor as the sow give birth to pigs. Coral reproduces by splitting at an alarming rate, it can split into halves, two in four, in the twinkling of an eye, it has many children. But they are all on a coral reef, you press me, and I squeeze you, confusion of parents and youngers. Some corals through the union of sperm and egg in sexual reproduction generate floating larvae which from the stomodaeum, drifting down with water, when they are in a suitable place, they attach and firm foot, develop into coral insects, for the growing population the coral Groups breed quickly, the old die, leaving the skeleton inform a reef; new coral insects climb on the predecessors. The predecessors fall, paving stones, the junior follow the remains of the older generation and continue to build new height. coral reefs are built up. Great Barrier Reef and other atolls, reefs, are also through such process.
