by: krystina, betul, athena, and priya. echinodermata have three germ layers. the germ layer is one...

By: Krystina, Betul, Athena, and Priya

• Echinodermata have three germ layers.

• The germ layer is one of the three main layers of these organisms

• The germ layer helps to form the various tissues and organs of the animal.

• As larva, the Echinodermata have bilateral symmetry.

• However, as adults they have radial symmetry.

• Radial symmetry allows them to move around in many different direction, although slowly.

• Echinodermata have no segmentation on their bodies.

• Echinodermata have a coelom.

• Coelom is a fluid or air filled space that separates the digestive tract of an organism from the outer body wall.

• The coelom of the Echinodermata Phylum is fluid-filled.

• Echinodermata have a saclike digestive tract with only one opening, meaning that food goes in and waste comes out of the same opening.

• The simplicity of a saclike digestive tract doesn’t allow for an organism to process different nutrients at different courses of digestion, as in a tube-like digestive tract with two openings.

• Echinodermata do not have cephalization, but their nervous system controls their body functions.

• Cephalization is common in organisms with bilateral symmetry and consists of a head and a central nervous system.

• Exoskeleton • Internal and

external parts radiate from the center

• Roughly spherical or dishaped

• No arms• 5 rows of tube

feet• Mouth ringed by

complex, jaw like structure

• 5 appendages

• An extension of the stomach known as “pyloric cecum” extends throughout each of the arms and supplies nutrients to all parts of the body, forming rings around the mouth closer to the top of the starfish

• have no true heart or anything that more than merely resembles a circulatory system.

• Have a well structured system of tubes that works in lieu for the circulatory system.

• uses some of the bumps or spines on its surface to take in oxygen.

• It has a gill structure to take in the oxygen.

• Oxygen from the water is distributed through the body mainly by the fluid in the main body cavity

• Releases carbon dioxide• It has a poorly developed

respiratory system.

• Sexual• commonly reproduce by free-

spawning: releasing their gametes into the water where they hopefully are fertilized by gametes from the opposite sex.

• To increase their chances of fertilization, gather in groups when they are ready to spawn, use both environmental signals to coordinate timing and chemical signals to indicate their readiness to each other.

• The females may hold the eggs on their surface, in the pyloric stomach or even attach them to the ground

• The gonads are located in each arm, and release gametes through ducts located on the central body between the arms.

• Salt water• Pacific , Indian, Atlantic, and

Arctic Oceans; as well as the region where the Southern Ocean and Antarctic Ocean merge.

• Can live in both tropical or cooler climates

• Usually live in rocky places. • can swim down to the bottom

of the sea where the amount of light that penetrates the water is very low or they can relax and float on top.

• often feed on tiny marine animals which inhabit the ocean floor