Section 26-3

Question 1

Cnidarians are members of phylum ??

Answer 1

Cnidarians

Question 2

What important features unite the cnidarians as a group?

Answer 2

Important features of cnidarians are soft-bodied, carnivorous animals with stinging tentacles arranged in circles around their mouths and have specialized tissues with body symmetry.

Question 3

What are cnidocytes

Answer 3

Cnidocytes are stinging cells that are located on the cnidarians’ tentacles

Question 4

A poison filled, stinging structure within a cnidocyte that contains a tightly coiled dart is called a ??

Answer 4

Nematocyst

Question 5

Is the follow sentence true or false? Cnidarians have bilateral symmetry

Answer 5

False

Question 6

What are the two stages in the cnidarian life cycle

Answer 6

a) polyp
b) medusa

Question 7

Look at diagram

Answer 7

Polyp and Medusa

Question 8

Gastroderm

Answer 8

Inner lining of the gastrovascular cavity

Question 9

Mesoglea

Answer 9

Layer that lies between gastroderm and epidermis

Question 10

Gastrovascular Cavity

Answer 10

Digestive chamber with single opening

Question 11

Nerve Net

Answer 11

Loosely organized network of nerve cells

Question 12

Statocysts

Answer 12

Sensory cells that help determine direction of gravity

Question 13

Ocelli

Answer 13

Eyespots that detect light

Question 14

Circle the letter of each sentence that is true about form and function in cnidarians.

A) In a polyp, the mouth points downward.
B) Materials that cannot be digested are passed out of the body through the mouth.
C) Cnidarians respire by diffusion through their body walls.
D) Most cnidarians reproduce sexually and asexually.

Answer 14

B, C, D

Question 15

What does a cnidarian’s hydrostatic skeleton consist of?

Answer 15

It consists of a layer of circular muscles and a layer of longitudinal muscles, as well as the water in the gastrovascular cavity.

Question 16

Cnidarian polyp can reproduce asexually by ??

Answer 16

Buddins

Question 17

In the Aurelia life cycle, how are young medusas released?

Answer 17

An aurelia polyp buds to release medusas

Question 18

Live lives primarily as medusas

Answer 18

Schohozoa - Jellyfishes

Question 19

Polyps of most grow in branching colonies; some lack a medusa stage

Answer 19

Hydrozoa - Portuguese man-of-war and hyrdas

Question 20

Have only the poly stage

Answer 20

Anthozoa - Corals and Sea Anemones

Question 21

What’s bioluminescence

Answer 21

Bioluminescence is the production of light by an organism. Jellyfishes use it to ward off the predators.

Question 22

How do hydras differ from other cnidarians in the class hydrozoa

Answer 22

They lack a medusa stage

Question 23

Circle the letter of each sentence that is true about corals
A) Corals secrete an underlying skeleton of calcium carbonate.
B) Corals are solitary polyps that live at all depths of the ocean.
C) Coral colonies growing near one another produce coral reefs.
D) Most corals are colonial.

Answer 23

A, C, D

Question 24

Is the following sentence true or false? Sea anemones are solitary polyps.

Answer 24

True

Question 25

How are corals reefs produced?

Answer 25

As colonies groups grow, they secrete an underlying skeleton of calcium carbonate. Many coral colonies growing near one another do produce coral reefs.

Question 26

What variables determine the worldwide distribution of corals?

Answer 26

temperature
water depth
light intensity

Question 27

What do corals depend on to capture solar energy, recycle nutrients, and help lay down their skeletons?

Answer 27

They depend on symbioses with algae

Question 28

Circle the letter of each way that coral reefs can be harmed
A) Sediments from logging can smother corals.
B) Overfishing can upset the ecological balance of coral reefs.
C) Algae can remove energy from corals.
D) Industrial pollutants can poison corals.

Answer 28

A, B, D

Question 29

What is coral bleaching?

Answer 29

High temperatures can cause symbiotic algae to be lost from the coral tissues, leaving behind only transparent cells atop ghostly white skeletons.