Echinodermata

Question 1

symmetry

Answer 1

pentaradial

Question 2

habitat

Answer 2

marine only

Question 3

Nerves

Answer 3

Nerve net (no brain, no ganglia, nerve going out each of the five arms), has very good power regeneration which allows it to regenerate the whole body (if a part of it is cut out)

Question 4

C. Asteroidea

Answer 4

don’t really use anus. Put stomach around the food. They are keystone species (they structure the community). They feed on mussel traditionally. Entire community depends on sea star to keep the species on track.

Question 5

C Ophiuroidea

Answer 5

Brittle stars: central disk offset from the arm. They have tube feet but no suction cup. They are relatively fast predator. They feed on dead stuff, filter feeder. As stuff flows by, it get trap in the mucus and pass the food down the tube feet. The arm can break down very easily, but the arm can regenerate. They can regrow pretty well.

Question 6

C Crinoidea

Answer 6

sea lilies, feather stars. They are found in deep water, sit at the bottom of sea, food passby, trap by the mucus, pass down by tube feet

Question 7

C Holothuroidea

Answer 7

sea cucumber: anatomically radial, but behaviorally bilateral. It doesn’t have spine, or pedicellariae. Defense system: by evisceration.

Question 8

C Echinoidea

Answer 8

sea urchin, heart urchins=sea biscuit, sand dollars (very flat, found at the bottom), internally they are all the same. Ex: pencil urchin (don’t really notice the spine) Tube feet is longer than the spine, attach themselves on the rock and trap flowing algae that flow by. The class is herbivores. Sea utter controls sea urchin. Spine is part of the endoskeletal. They are found at rocky bottom water (Eel grassbeds).