CATDOLL : CATDOLL: A brief overview of the long-spined sea urchin

A brief overview of the long-spined sea urchin

Distributed in the Indian Ocean and the western Pacific Ocean, it is a large sea urchin with an inner shell diameter of more than 10 cm and black spines of more than 15 cm, which are poisonous. They live in tide pools or near low tide lines in coral reef areas, sometimes appearing in groups. They come out at night to feed on algae on rocks. The breeding season is in July. They have an anal papilla on their bodies, which is clearly visible on the back of the sea urchin.

The spines and shells of sea urchins are easily damaged but also easily repaired. Why do they have such a strong regenerative ability?

Sea urchins use their spines to "see" Technically, sea urchins don't have eyes. But they know how to use their spines to "see". A new Duke University study shows that sea urchins can apparently judge what's around them based on the light reflected by their spines. In the experiment, the researchers placed 20 sea urchins in a water tank with light, which included two black discs of different sizes.

The researchers found that the urchins had almost no reaction to the small discs. However, when light hit the larger discs, the urchins reacted differently depending on the intensity of the light. Some urchins fled as quickly as possible from the larger discs, while others moved closer to them. Based on these findings, the researchers believe that sea urchins have vision similar to nautilus, horseshoe crabs, and some other marine invertebrates with eyes. However, sea urchins' vision is still very limited.

Sea urchins are a class of Echinodermata, a type of invertebrate that lives in shallow ocean waters. The main features are that the body is spherical, disc-shaped or heart-shaped, and it has no arms. The internal skeleton is fused together to form a solid shell.

Most species have a complex chewing organ in their mouths, called Aristotle's lantern, which has teeth on it for chewing food. The digestive tract is long and tubular, coiled inside the body, and feeds on algae, hydras, and worms. Most are dioecious, and during individual development, they transform into sea urchin larvae (long arms) and then into young sea urchins, which reach sexual maturity after 1-2 years. They can be divided into two subclasses, the regular echinoids and the irregular echinoids, and 22 orders. There are more than 900 living species belonging to 225 genera. About 100 species are known in China, and about 7,000 fossil species.

Because they have a lot of highly active regenerative cells

The cells have high omnipotence and can regenerate even if the stratum corneum is detached.

This kind of evolution in nature is to survive better and protect oneself better.

Forced by natural selection, in order to survive better in the environment.