The general shape of the echinoderm may be that of a star with arms extended from a central disk or with branched and feathery arms extended from a body often attached to a stalk, or it may be round to cylindrical.


What is unique to echinoderms? First, they all possess five-part radial symmetry around a central disk. Second, they all possess a very unique water vascular system (vascular system based on water). These unique characteristics distinguish echinoderms from other animals in the animal kingdom.

how do you identify echinoderms?

Characteristics of Echinoderms Their mouth is situated on the underside and their anus on top (except feather stars, sea cucumbers and some urchins). Echinoderms have tentacle-like structures called tube feet with suction pads situated at their extremities.

How are echinoderms harmful to humans? No, echinoderms are life threatening to humans. However, the spines of echinoderms can cause a nasty sting if touched and these spines generally break off and remain stuck in the skin.

Do echinoderms have a brain? Echinoderms such as starfish (more accurately referred to as sea stars), brittle stars, sea urchins and sea cucumbers do not have a brain or a brain-like organ in their bodies.

Where are echinoderms found? The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone.

How do echinoderms eat? Echinoderms are a diverse group with an equally diverse range of feeding habits. They graze on algae, filter plankton out of the current, mop up loose food particles from the bottom, slurp up sand and mud, pry apart mussels and oysters and digest them in the shell, there are even Brittle Stars that Trap and Eat Fish.

Do all echinoderms have an endoskeleton?

There are four basic things that undeniably make an echinoderm an echinoderm. First, they all have calcitic skeletons, being composed of calcium carbonate crystals. In most cases, a thin tissue surrounds the skeleton, making it an endoskeleton, but for all intents and purposes the skeleton acts as an exoskeleton.

How do echinoderms reproduce?

Echinoderms reproduce sexually. In most echinoderms, eggs and sperm cells are released into open water, and fertilization takes place when the eggs and sperm meet. This is called external fertilization, and is typical of many marine animals.

What characteristics do all echinoderms have in common?

This phylum exists exclusively in the sea, and cannot be found on land or in fresh water. All echinoderms have one thing in common: radial symmetry. This means that the creatures have appendages (or body construction) which point outward from the center of the body like the spokes on a bicycle wheel.

What do echinoderms have instead of a brain?

Instead of a brain, echinoderms have a ring of nerves located around their mouth area that governs their nervous responses. This ring coordinates their motion, their eating, basically anything that requires nerve control.

Do echinoderms have a hydrostatic skeleton?

Hydrostatic skeletons have a role in the locomotion of echinoderms (starfish and sea urchins), cnidarians(jellyfish), annelids (earthworms), nematodes, and other invertebrates. They have some similarities to muscular hydrostats. “A hydrostatic skeleton, or hydroskeleton, is a skeleton supported by fluid pressure.

Do sea urchins reproduce asexually?

Sea Urchin Dev. Fertilization is the union of two gametes, the sperm and the egg to create a new organism. Although some unicellular animals reproduce asexually, sexual reproduction is the preferred method of propagation in most multicellular animal species.

Do echinoderms have bones?

The skeleton of echinoderm is internal; that is, it is an endoskeleton. It is made of calcium carbonate (calcareous). Vertebrates also have an internal skeleton made of bones and cartilage. Some molluscs have a calcareous shell that functions as an exoskeleton.

Do echinoderms have a notochord?

Echinoderms are deuterostome marine organisms. Echinoderms possess a water-based circulatory system. The madreporite is the point of entry and exit for water for the water vascular system. The characteristic features of Chordata are a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

Where do most echinoderms live?

Where Do Echinoderms Live. Echinoderms are marine organisms which means they live in the ocean. They are found in all marine waters on Earth although there are few species living in the Arctic. Many echinoderms are visible on the seashore such as sand dollars, globular spiny sea urchins and asteroids.