Chapter 27.2

Question 1

What are four examples of cnidarians?

Answer 1

Hydras, corals, jellyfish, and sea anemones

Question 2

Where do most cnidarians live?

Answer 2

In the ocean

Question 3

What is the gastrovascular cavity?

Answer 3

The hole for digestion

Question 4

Where is the epidermis?

Answer 4

Outside

Question 5

Where is the gastrodermis?

Answer 5

Inside

Question 6

Where is the mesoglea?

Answer 6

The gel in between the epidermis and the gastrodermis

Question 7

How are the cells of cnidarians arranged?

Answer 7

Into tissues

Question 8

What kind of symmetry do cnidarians have?

Answer 8

Radial

Question 9

What are the two basic forms of cnidarians?

Answer 9

Medusa and polyp. Cnidarians can be either or alternate between

Question 10

Describe and give an example of medusa

Answer 10

Free-floating and umbrella shaped, jellyfish

Question 11

Describe and give an example of polyp

Answer 11

Tubelike and often attached to a rock or other object, anemones

Question 12

How are their nerve cells arranged and what do they do?

Answer 12

Into a nerve net where they coordinate sensory and motor activities

Question 13

What can sensory cells detect? (3)

Answer 13

Light, chemicals and mechanical stimuli

Question 14

What do the muscle-like cells if cnidarians do?

Answer 14

Aid in feeding and digestion

Question 15

What are cnidocytes?

Answer 15

Stinging cells that are located in the finger like tentacles that surround the opening

Question 16

What does the one opening of a cnidarian function as?

Answer 16

Mouth and anus

Question 17

What is a nematocyst?

Answer 17

A threadlike organelle located in the cnidocyte that may contain toxins and is used for defense and to capture prey

Question 18

How do cnidarians reproduce?

Answer 18

Sexually and asexually

Question 19

Describe the life cycle of Obelia

Answer 19

Alternation between a polyp and a medusa stage. Once the gametes fuse, a planulae forms as a free-swimming larve

Question 20

What is the common qualities of cnidarians?

Answer 20

The presence of stinging cells

Question 21

Name the three types of cnidarians

Answer 21

Hydrazoans
Scyphozoans
Anthozoans

Question 22

What are three examples of hydrazoans, and how advanced are they?

Answer 22

Obelia, hydras, Portuguese man of war

Most primitive

Question 23

What is another name for scyphozoans, and how do they get food?

Answer 23

Jellyfish, active hunters

Question 24

What are two examples of anthozoans and what do they exist as?

Answer 24

Sea anemones and corals. They exist only as polyps.

Question 25

Where are sea anemones found and how do they eat?

Answer 25

Costal areas attached to rocks. They feed on whatever swims within their tentacles.

Question 26

Name the colonies of coral polyps

Answer 26

Coral reefs

Question 27

What is the skeleton of coral polyps made of?

Answer 27

calcium carbonate

Question 28

Where are coral reefs found?

Answer 28

Tropical regions in warm and clear oceans

Question 29

What are the two main benefits that coral reefs give?

Answer 29

Protect coastlines and provide food for fish