Echinoderms Worksheet
Fill in the blanks. Use pages 136 – 139 of the red marine biology book.
Echinoderms: Five-Way Symmetry
1)Echinoderms are Click here to enter text. symmetrical, like cnidarians and combjellies.
2)Unlike cnidarians, most echinoderms have Click here to enter text.radial symmetry (based on 5 parts.)
3)Echinoderms haveanClick here to enter text.skeleton like we do.
4)Unique to echinoderms is the Click here to enter text.system, a network of Click here to enter text.filled canals.
5)Click here to enter text.are muscular extensions of these canals.
6)In sea stars and sea urchins the system connects to the Click here to enter text.on the aboral surface.
Types of Echinoderms
Class Asteroidea
7)Sea stars (class Click here to enter text.) are sometimes called star fishes.
8)Most species have Click here to enter text.arms that radiate from a Click here to enter text.disk.
9)Some have more than five, sometimes close to Click here to enter text.!
10)Sea stars can move in any Click here to enter text.(slowly) by reaching out their Click here to enter text.and pulling themselves along.
11)The aboral surface is covered with Click here to enter text.modified into pincer-like organs called Click here to enter text..
12)Most sea stars are Click here to enter text.of bivalves, snails, and Click here to enter text..
Class Ophiuroidea
13)Brittle stars (class Click here to enter text.) have aClick here to enter text.shaped body architecture.
14)The five arms are Click here to enter text.and very Click here to enter text..
15)The swift, Click here to enter text.-like movements of the arms are used in Click here to enter text..
16)The tube feet, which lack Click here to enter text., are used inClick here to enter text..
17)Most brittle stars eat particulate Click here to enter text.matter and small animals.
18)Brittle stars are not always visible, often hiding under Click here to enter text., coral, or covering themselves with Click here to enter text..
Class Echinoidea
19)In sea urchins (class Click here to enter text.) the endoskeleton forms aClick here to enter text.,rigid test (shell).
20) In sea urchins the mouth is on the Click here to enter text.and the Click here to enter text.is on the top.
21)The plates that make up the Click here to enter text.can be seen when the urchin is cleaned ofClick here to enter text.and tissues.
22)Sea urchins graze on attached or drifting Click here to enter text.and sea grasses.
23)The mouth has an intricate system of Click here to enter text.and muscles called Click here to enter text..
24)Not all urchins are round with prominent spines. Click here to enter text.urchins and Click here to enter text.are adapted to live in Click here to enter text.bottoms by having Click here to enter text.bodies and short spines.
Class Holothuroidea
25) Sea cucumbers (class Click here to enter text.) are superficially Click here to enter text..
26)They do not have Click here to enter text.and lack Click here to enter text.symmetry.
27)The sea cucumbers lie on one side, where Click here to enter text.rows of tube feet are concentrated.
28)The Click here to enter text.andClick here to enter text.surfaces are at the ends.
29)Many sea cucumbers are Click here to enter text.feeders.The tube feet around the Click here to enter text.are modified into Click here to enter text.tentacles they use to pick up organic matter.
30)Sea cucumbers evolved defense mechanisms such as:
a)Secrete Click here to enter text..
b)Expulsion of the Click here to enter text.and internal Click here to enter text.
31)This Click here to enter text.distracts the offender while the sea cucumber escapes.
Class Crinoidea
32)Crinoids (class Click here to enter text.) are Click here to enter text.feeders that use Click here to enter text.outstretched arms to obtain food and water.
33)Crinoids include Click here to enter text.stars and sea Click here to enter text..
34)Sea lilies are restricted to Click here to enter text.water while feather stars Click here to enter text.and crawl on hard bottoms.
35)Some crinoids have only Click here to enter text.arms but most have up to Click here to enter text.because the first five branch off.
Biology of Echinoderms
36)How do sea stars feed? TheyClick here to enter text. orClick here to enter text.part of their stomach inside out through the Click here to enter text.to envelop the food.
37)The stomach secrets Click here to enter text.produced by digestive glands.
38)The gut of sea urchins is Click here to enter text.andClick here to enter text. .This adaptation helps them break downClick here to enter text. material.
39)In all echinoderms nutrients are transported in Click here to enter text.fluid. This fluid also transports Click here to enter text.because they lack a Click here to enter text.system.
40)The echinoderm nervous system looks very simple. They have a Click here to enter text.net. The nervous system Click here to enter text.movement of tube feet and Click here to enter text.in the absence of a brain. But they are also capable of more complex behaviors such as :
a)Click here to enter text.
b)Click here to enter text.
41) Most echinoderms have Click here to enter text.sexes. They shed Click here to enter text.orClick here to enter text.directly into the water.
42)The Click here to enter text.do not survive long in the water so many species Click here to enter text.all at once to ensure Click here to enter text..
43)Echinoderm larvae are Click here to enter text.symmetrical.
44)Asexual Click here to enter text.takes place regularly in some sea stars, Click here to enter text., and sea cucumbers. The centralClick here to enter text. separates and divides the body into Click here to enter text.pieces.
45)Click here to enter text.is the ability to grow lost or Click here to enter text.body parts.
46)In some Click here to enter text.a severed arm can grow into a new Click here to enter text.. But in most, the arm must contain a portion of the Click here to enter text.disk to regenerate.