In the depths of the seas with oceanic salinity live amazing animals - sea urchins.This creeping arthropod belongs to a class of echinoderms.Hedgehog has a small body (3-30 cm), covered with shell of calcareous plates, which are connected to different along the length of the needle.They are necessary for the movement of the animal.The eyes are located in the upper part of the body.
In nature, there are sea urchins most diverse paint: red, white, black, green, blue, brown, purple and gray.Some individuals change color depending on the ambient noise.The total number of legs fitted with suction cups and located throughout the body, can be more than a thousand.They are able to stretch and shrink, so the animal can easily crawl from place to place, as well as navigate through the cliffs.Mouth tighten delicate skin, consists of five pairs of rounded chewing plates, the edges of which are external gills.Sea urchins have special organs of equilibrium - sferidii.They are located around the mouth.The sea urchin has special grasping bodies - pedicellariae located among the needles.They are equipped with head poisonous liquid produced by special glands.Poison animal is very toxic.With the help of the hedgehog fights with enemies.However, this is not the only function pedicellariae - thanks to them, hedgehog cleans your body of waste and various contaminants, as well as production captures and transmits it to the mouth.
arthropods inhabit in depths of up to ten meters, mainly around coral reefs and coastal waters.Despite the presence of a variety of ways to protect (the needle pedicellariae, shell), the animals often fall prey to larger animals, such as sea crabs, fish, shellfish, marine mammals and birds.
reproduce individuals begin after the third year of life.Germ cells in arthropods located near the anus.Sea urchins can reproduce all year round.However, most of the mating season occurs in the warm time of year.Since these aquatic animals are dioecious, breeding hedgehogs as follows: the female lays her eggs in shallow water, and then the males fertilize it.Millions of male germ cells and testicular emitted by marine arthropods, a few hours turn into tiny beads coated with thin fibers.Thanks to their vibration, the eggs are able to rotate and move in all directions.After some time, the larva mutate: stretched, forming a very thin calcareous skeleton and four long process.Since that time the egg loses its former buoyancy, and carries within them in different directions.During the period of wandering and metamorphosis occurs.At the base of processes and pleutusah formed and develops tiny sea urchin.At this point, the larva drops to the bottom or other surface populating new space.There were first leg firmly attached to the rocks, and the animal begins to actively grow.
In coastal countries, the sea urchin is a target species.In the Mediterranean countries especially appreciated dishes from milk and eggs animal.However, this arthropod bears a danger to humans.Bathing in the sea, and accidentally stepped on a hedgehog, you can cause serious damage to the foot.Piercing the human skin, the needle is often broken, leaving the body of toxic ends.This gives rise to severe pain lasting several hours.The venom of some representatives of this type is very toxic.
however undeniable and the use of sea urchins.They are known as the orderlies of the deep sea, thanks to its ability to absorb carbon dioxide, reducing its amount in the atmosphere.The insides of the animal is widely used in the pharmaceutical industry for pharmaceutical purposes.
