echinoderms quiz

3 characteristics that ALL echinoderms have

•  (tube feet, radial symmetry, spiny skin)

Explain how the water vascular system works to help move the tube feet of an echinoderm

• water pressure in hydraulic canals forces tube feet to extend and contract, allowing for movement across the bottom of the seafloor

List 6 different animals that are echinoderms

• (sand dollar, sea urchin, sea star, brittle stars, feather star, and sea cucumber)

Explain the unique way in which sea stars eat

• push their stomach inside out, digest their prey, and then slurp it up like a smoothie

Identify and explain the purpose of the madreporite

• regulates water going in and out of the water vascular system to control the movement of the tube feet

Explain the purpose of evisceration and identify which echinoderms can do this

• sea cucumbers do this by expelling non essential organs out of their anus. It is used to scare away predators or help the sea cucumber escape

Identify the purpose “Aristotle’s Lantern” and which echinoderm has this

• the sea urchin - used as a feeding structure to eat algae

Identify which echinoderm can swim for brief periods of time

feather stars

The word “Echinoderm” means:

SPINY SKIN

Which echinoderms can be filter feeders?

• feather stars, some brittle stars, some sea cucumbers, sand dollars

Which echinoderm pushes its stomach out of its body to feed?

sea stars 

Explain the difference between how a sea urchin gets around versus how a brittle star moves

Sea urchins move with their tube feet. Brittle stars crawl with their arms and their tube feet are used to move food towards their mouths, and not for locomotion

Describe a situation in which a sea cucumber would eviscerate

When being attacked by a predator to help it escape

Why is it difficult to remove a sea urchin spine if it is embedded in the skin?

It has a barb on the end which makes it difficult to remove

What is the oldest group of echinoderms?

Feather stars

Why is the mouth of most of the echinoderms underneath their bodies

They live on the bottom of the ocean, so their mouth is located where they are easily able to access food