INTRODUCTION TO ECHINODERMS An animal with an endoskeleton

INTRODUCTION TO ECHINODERMS

An animal with an endoskeleton (covered by thin layer of ciliated tissue) and spiny skin (made of calcium carbonate). ALL Echinoderms are marine animals. They have no posterior or anterior ends. Most of their bodies are two sided. oral: where the mouth is located aboral: opposite side. Echinoderms also lack a head. Known exclusively for their rows of poisonous spines along their arms. Feeds exclusively on coral WHAT IS A ECHINODERM? Crown-of-thrown reefs (sea star) exclusively a threat to coral

They have bilateral symmetry until they become adults. As adults they develop a pentamerous (five part) radial symmetry. Water vascular system: a system of internal tubes. It is filled with fluids that carried out respiration, circulation, and movement. Tube Feet: structure that function much like a suction cup. They are used for attachment, locomotion, and for receiving chemicals and mechanical stimuli. Spines and pointed bumps protect them from predators. CHARACTERISTICS

GROUPS OF ECHINODERMS *THEY ARE LISTED IN THE HOMEWORK Sea Star: -most of the time they have 5 arms and a central disk. -use tube feet to move along -they can grow any missing part as long as the central part remains. -Pedicellariae (spines modified into pincer like organs) help the sea star’s surface remain clean. -They are carnivores (eat snails, mollusk and other moving animals).

Groups of Echinoderms Brittle Stars *they are listed in the homework -the tube feet are used for feeding (they like suckers). -they lack an anus -they have the most amount of species in any group of Echinoderms. -they often hide under corals and rocks or cover themselves with mud or sand to escape predators

Groups of Echinoderms Sea Urchins - aremove listed in the homework Their spines help*they them - Mouth is in the bottom and anus is on top. - In the tropics they show a variety of shapes and sizes, particularly on coral reefs. - Sand dollars are adapted to live in the bottom of the ocean. - They use their tube feet to pick up organic particles (food).

Groups of Echinoderms Sea Cucumbers *they are listed in the homework -they have no spins and lack radial symmetry -most are deposit feeders -they extend their tentacles to obtain food -when they feel threatened they release a sticky toxic filaments through the anus -evisceration?

Groups of Echinoderms Crinoids (Sea Lilies and Feather Stars) - *they are listed in the from homework They use feathery arms to obtain food the water - Sea Lilies are restricted to deep water and attached to the bottom - Feather stars they perch and crawl everywhere (they are capable of graceful swimming). - Food makes its way into them (they tilt to make the process easier).

In all echinoderms nutrients are transported in the fluid that fills the extensive body cavity (coelomic fluids). Many feed by extending, or everting, part of their stomach inside out through the mouth to envelop the food. The digested food is carried into the gland pushes the stomach back in. Digestive waste is released as feces through the anus (only on some echinoderms). FEEDING AND DIGESTION

The nerve net is essential because they have no brain They have scattered sensory cells that detect light, gravity, and chemicals released by potential prey. Reproduction System They external fertilization (spawning) - Sexes are separate in most echinoderms -Sperm (produced in testes) and eggs (produce in ovaries) -Many species spawn all at one to ensure fertilization NERVOUS SYSTEM -they reproduce asexually -regeneration ( ability to grow any body part back) �

Sea Urchins: help control the distribution of algae and other forms of marine life. Sea Stars: important predators that help control the number of other organism such as the clams and corals. ADDITIONAL INFO