Chinese pinyin: h m: I x: ng

Starfish is a class of Echinoderm, which is divided into two families: petrel and starfish, but people commonly call it starfish or "star fish".

Starfish are mainly distributed in shallow seabed sand or rocks all over the world, and we are no strangers to it. However, we know little about its ecology. Starfish doesn't look like an animal, and from its appearance and slow movement, it's hard to imagine that starfish is a greedy carnivore, which plays an extraordinary and important role in marine ecosystem and biological evolution. This is why it is widely distributed in the world.

Also translated as star fish; Also called sea star. Echinodermata (Echinodermata) A general term for marine invertebrates of the class Asteroidea, which is not a fish. Flat and star-shaped. Wrist. There are11,800 species in existence, which are found in various oceans, with the most species in the northern Pacific Ocean. Radial diameter 1? 6? 565 cm, mostly 20? 6? 530 cm (8? 6? 5 12 inch). The wrist is hollow and covered with short spines and forked spines; There are rows of tube feet (some with suction cups at the end) in the ditch below, so that starfish can crawl in any direction, even climb a steep surface. Lower starfish feed on food grains along the entrance of wrist groove. Higher kinds of stomachs can be turned over to the bait for in vitro digestion or swallowed whole. The endoskeleton consists of a calcareous bone plate. Breathe through the skin. There is a bright spot on the wrist. Most of them are hermaphroditic and a few are hermaphroditic; Some are asexual.

The species of Phanerozonia have obvious marginal plates, sucker at the foot of the tube, and may have no anus. Including most deep-sea species, such as Albatrossaster richardi, which is found at a depth of 6,035 meters (19,800 feet). The radial diameter of the mud starfish (Ctenodiscus crispatus) is about10cm, the wrist is short and blunt, the body plate is wide and yellow, and it is abundant in the mud bottom along the northern coast. Northern genera such as Astropecten, Psilaster and Luidia with long and sharp wrists and spines at the edges. The largest reticular starfish in the West Indies has a radial diameter of about 50 cm (20 inches). The genus Linckia, which is mostly found in the Indian Ocean-Pacific Ocean, can grow into a new individual from a small wrist.

There are Spinulosa with clusters of spines, and there are suction cups at the foot of the tube, but forked spines are rare. Asterina gibbosa is a common camel petrel in the rocky seabed of Europe. In the north, the genera Crossaster and Solaster have many short wrists and wide body plates. Crossaster papposus has 15 wrists. Forcipulata has two-valved forked spines with long stalks, which can protect or feed. Common species that feed on bivalves in shallow water include Asterias rubens distributed in northern Europe and A. amurensis from Bering Sea to Korean Peninsula. Pisaster brevispinus on the west coast of North America is 65 cm (26 inches) long and is one of the largest starfish in the world, feeding on sand money sea urchins and so on. There are 15 Pycnopodia helianthoides from Alaska to California. 6? 524 wrists. Heliaster in China and America have up to 50 wrists.

Prey on Protoreaster nodosus, a kind of starfish.

People generally think that sharks are ferocious carnivores in the ocean. And who would have thought that starfish, which inhabit the seabed sand or rocks and are usually motionless, are also carnivores! But that's actually the case. Because starfish can't move as flexibly and rapidly as sharks, its main prey is some slow-moving marine animals, such as shellfish, sea urchins, crabs and anemones. It often adopts a slow and tortuous strategy to approach the prey slowly, catch the prey with the tube foot on the wrist and wrap the whole body around it, spit out the stomach bag from its mouth, and use digestive enzymes to dissolve the prey in vitro and be absorbed by it.

We know that starfish is an indispensable link in the marine food chain. Its predation plays a role in maintaining the balance of biota. For example, on the west coast of the United States, there is a kind of spiny starfish that often preys on the sea rainbow (talking about vegetables) that is densely attached to the reef. In this way, the excessive reproduction of sea rainbow can be prevented, and the sea rainbow can be prevented from invading the territory of other creatures, so as to maintain the balance of biota. There are about 2000 species of starfish in the world, which are distributed in the vast territory from the sea to the seabed. Among them, the northeast Pacific waters from Alaska to California have the most species.

Starfish, sea cucumber and sea urchin belong to echinoderms. They usually have five wrists, but there are also four or six, and some have as many as 40 wrists. There are four rows of dense tube feet under these wrists. Using tube feet can not only catch prey, but also allow yourself to climb on the rocks. The big starfish has thousands of tube feet. Starfish's mouth is in the middle of its lower body, which can be in direct contact with the surface of the object that starfish has climbed. Starfish vary in size, from 2.5 cm to 90 cm, and their body colors are different. Almost every one is different. The most common colors are orange, red, purple, yellow and cyan.

In the food chain of nature, the contest between predator and prey is often life and death. In order to escape starfish, almost all prey animals can make escape response. There is a big sea cucumber. Whenever a starfish touches it, it will roll violently in the water and run away before it is firmly caught by the starfish. Scallops also have unique skills in avoiding starfish. When the starfish approaches it, scallops will swim quickly one by one. There is a small anemone. Whenever a starfish approaches it, it breaks away from the climbing rocks and drifts to a safe place. The escape ability of these animals comes from long-term evolution. Avoid the fate of being eliminated by nature.

Although starfish are ferocious predators, they are gentle with their offspring. Starfish often erect their wrists after laying eggs, forming an umbrella for eggs to hatch in, so as not to be preyed by other animals. The hatched larvae drift with the sea water and feed on plankton, and finally grow into starfish.

Starfish feed on shellfish. When starfish want to eat mussels, they will first open the shells with powerful suction cups, and then stick their stomachs out of their mouths to eat the mussels. Therefore, the economic value of starfish is not great, and it can only be dried and powdered for agricultural fertilizer. Because it preys on shellfish, it is very harmful to shellfish culture.