Echinoderms

What happens when sea cucumbers are threatened

they may expel their internal organs; then, these organs regenerate in a few weeks

what are their tube feet used for then

to move particles of food into their mouth

What are tube feet

hollow, thin-walled tubes that each end in a suction cup; as the pressure in the tube feet changes, the animal is able to move along by pushing out and pulling in its tube feet

Do Echinoderms have a head or brain

No

What are soft-bodied echinoderms that have a leathery covering and tentacles around their mouth and rows of tube fee on their upper and lower surfaces

sea cucumbers

What are disk or globe-shaped animals covered with spines

sea urchins, sea biscuits and sand dollars

How do sea stars reproduce

sexually when females release eggs and males release sperm into the water

what does Echinoderm mean

Spiny skin (echinos-spiny; derma-skin)

sea urchins

have sacs near the end of the spines that contain toxic fluid that is injected into predators; spines also help in movement and burrowing

How does the brittle star grow new parts

regeneration

How do sea stars repair themselves

regeneration-grows a new limb if it loses one

Whats the largest group of echinoderms

sea stars

Other groups include what

1. Brittle stars 2. sea urchins 3. Sand dollars 4. Sea cucumbers

Characteristics of these

1. Hard endoskeleton 2. covered by a thin, bumpy or spiny epidermis 3. Radially symmetrical-allows them to sense food, predators and other things in their environment from all directions

What three things do all echinoderms have

1. Mouth 2. Stomach 3. Intestines

What echinoderm has fragile, slender, branched arms that break off easily

The brittle star

how do brittle stars move

Using their flexible arms-NOT tube feet

what do sea urchins feed on

algae

Why are brittle stars called that

because their arms break off so easily if they are grabbed by a predator

Other echinoderms feed on what

dead and decaying materical called detritus

what do sea cucumbers eat

detritus and plankton

Why are echinoderms of value

1. they feed on dead organism and help recycle material 2. sea urchins control the growth of algae 3. sea urchin eggs and sea cucumbers are used for food i some places 4. they are used for research and may be sources of medication 5. sea stars control populations of other animals

how far do echinoderms date back

400 million years ago

How many species of echinoderms exist

6,000

what do they have though

A nerve ring that surrounds the mouth; also cells that respond to light and touch

why are they so important

Echinoderms more closely resemble animals with backbones than any other group of invertebrates, since they have complex body systems and an embryo that develops the same way that the embryos of animals with backbones develop

What characteristic is unique to Echinoderms

Have a water-vascular system that allows them to move, exchange carbon dioxide and oxygen, capture food, and release wastes

Describe sand dollars

Have no arms, but have a 5-pointed pattern on their surface

How many of the 6,000 are sea stars

More than 1/3

What type of echinoderm has at least five arms arranged around a central point and their arms are lined with thousands of tube feet?

Sea stars

What is the water-vascular system

a network of water-filled canals with thousands of tube feet connected to it

sand dollars

are covered with stiff, hairlike spinds

what do sea stars feed on

worms and mollusks