**Echinoderms** are animal species under the phylum Echinodermata. These species are characterized by having spiny skin, internal skeleton, water vascular system, and cuplike suction on the ventral portion of their body called *tube feet*. Most adult species appear to have five-part radial symmetry.

**Echinoderms** are animal species under the phylum Echinodermata. These species are characterized by having spiny skin, internal skeleton, water vascular system, and cuplike suction on the ventral portion of their body called tube feet. Most adult species appear to have five-part radial symmetry.

The **water vascular system** functions to carry out important body processes including movement, nutrient circulation, and respiration. The system is filled with fluid, and it opens to the outside through a sievelike organ called **madreporite**.

There are roughly 7000 to 8000 species of **echinoderms** all over the world and all of them are found in marine environments. The major groups of echinoderms include sea urchins, brittle stars, sea stars, sea cucumbers, and feather stars.

**Sea urchins and Sand dollars** are echinoderms that have unique large, solid plats that create a box around their internal organs. These organisms are mostly detrivores or grazers that feed on large amounts of algal species.

**Brittle stars** are animal species usually found in coral reefs. They have slender, thin, and flexible arms that can help them escape their predators quickly. Brittle stars are very fast-moving, and they are known to be filter feeders and detrivores.

**Sea cucumbers** are warty moving pickled-shaped animals that are also detritus feeders. They move along the floor of the sea as they feed and suck organic materials on the ocean floor.

**Sea stars** are the most commonly known **echinoderms**. These animal species move by creeping slowly along the floor of the ocean using their tube feet. Sea stars have the ability to regenerate and repair their damaged part as long as it has the central part of the body.

**Sea lilies and Feather Stars** are filter feeder organisms found mostly in tropical marine environments. They are characterized by having long, feathery arms.

**Tube feet** function like suction cups that help organisms attach to the surface for a period of time. The muscles pull the tube feet backward so that it creates suction to the surface. So many of them can be quite powerful.

In the marine ecosystem, deuterostomes such as echinoderms are considered as key consumers. Echinoderms are either suspension feeders, deposit feeders, or predators.

In addition, echinoderms have an oral end or anus that releases nitrogen-containing wastes into the environment. Their wastes help increase the nitrogen level in the environment, which in turn help the distribution and growth of photosynthetic autotrophs such as algae. Algae are considered as an important part of the marine food web.

**Sea stars** are the most commonly known echinoderms. These animal species move by creeping slowly along the floor of the ocean using their tube feet. Sea stars have the ability to regenerate and repair their damaged part as long as it has the central part of the body. *In fact, if the sea star is broken into pieces each piece can still grow into a new individual sea star as long as t contains the central body of the organism*.

Therefore, it would be very ineffective to tear these organisms apart and then throw them back into the marine environment because they will rather increase in population.