The fertilized eggs from part of the zooplankton however some brood their eggs by sitting over them or in some have specialized brooding baskets on their aboral surface. Sea Star reproduce by releasing their gametes into the environment. The tube feet, especially those at the tips of the rays, are also sensitive to chemicals. The tube feet, spines, and pedicellariae found on sea stars are sensitive to touch, while eyespots on the ends of the rays are light-sensitive. The ring nerves and radial nerves coordinate the sea star's balance and directional systems.Although the echinoderms do not have many well-defined sensory inputs, they are sensitive to touch, light, temperature, orientation, and the status of water around them. The esophagus is also surrounded by a central nerve ring which sends radial nerves into each of the arms, often parallel with the branches of the water vascular system. Starfish have interlacing nerves called nerve plexus which lie within and beneath the skin. Starfish have a complext nervous system, but lack a centralized brain. The way a starfish will divour shellfish is by using its feet to grasp and prie open the shell by wearing out the adductor muscle then inserting its stomach into the shell to eat the the contents of the shellfish. Others consume coral, sponges, even plankton. Some eat dead, decomposing animals and plants. Most Sea Star are generalist predators, many eating mollusks like clams, oysters, snails, and any other animal that cannot evade a Starfish attack. The Sea Star like many Echinoderms have a delicate internal balance so none will be found in freshwater or within teh water column. Even here in washington in cold-temperate water and even in alaska yoiu can find star fish. Many Sea Star can be found in the tropical pacific areas such as australia. Many starfish can be found on coral because it a food source for them. It lives anywhere from small holes left by other creatures in rocks and coral reefs. Sea Star can be found manly on the bottom of the sea floor. It is known that there are over 1800 verieties of starfish living today. The interesting thing is that Sea Star house many of their vital organs in their rays so if one does drop off not only can that starfish regenerate another arm, but the arm can regenerate a completely new Sea Star. If a Sea Star is threatened by a predator then it can choose to drop that arm in order to get away. The most interesting thing about Sea Star is their ability to regenerate or grow limbs back. Madreporite pump water into the body creating a suction at the end of the tube feet which can be seen in rowns on the underside of each ray. Sea Star are part of a group called echinoderms which means "Spiny Skin." Sea Star also widely known as "Starfish" have five puple eyespots at the end of each ray and a bright orange dot in the center called teh madreporite. They have five arms (rays) connected to a round body. Adult sea stars avoid predation with their strong chemical defences and sharp spines, but a few predators, such as crayfish, are not deterred and may eat sea stars.Sea Starare related to brittle stars, sea urchins, sea cucumbers, and sand dollars. Chemical defences under their skin to deter predators.įish prey upon very small, juvenile sea stars.This means that the sea star can physically divide itself into 2 to reproduce. The ability to reproduce by releasing a free-swimming larval stage, as well as through fission or asexual reproduction.A complex network of nerves, called a nerve net, that serves the same purpose as the central nervous system in humans.Some sea stars can even regenerate a new animal from one limb. The ability to regenerate a lost limb.Structures on the ends of their arms that help them to detect changes in light. The stomach then covers the prey and digestion begins. When a sea star feeds, it is able to push the lower part of its stomach out through its mouth. A mouth that is located in the centre of their bottom side (the ventral surface).Hundreds of tube feet, which help feeding and movement.Spines or spicules covering the top (or dorsal) surface.Hard plates under their skin instead of a backbone.Sea stars are a diverse group of animals, but most of them share the following characteristics:
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