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2. Standardized Test Prep
Resources
Chapter Presentation
Visual Concepts
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Standardized Test Prep

3. Chapter 33 Table of Contents Section 1 Porifera
Sponges, Cnidarians, and Ctenophores
Chapter 33
Table of Contents
Section 1 Porifera
Section 2 Cnidaria and Ctenophora

4. Chapter 33 Objectives Describe the basic body plan of a sponge.
Section 1 Porifera
Chapter 33
Objectives
Describe the basic body plan of a sponge.
Describe the process of filter feeding in sponges.
Contrast the processes of sexual and asexual reproduction in sponges.

5. Chapter 33 Body Plan of Sponges Section 1 Porifera
The phylum Porifera is made up of sponges.
Sponges are sessile invertebrates that have no true tissues or organs. The simplest sponges are shaped like hollow cylinders.
The body wall of a sponge is composed of two layers of cells that are separated by a jellylike substance called mesohyl.
Choanocytes in the interior layer draw water through the ostia that penetrate the body wall. The water leaves through the osculum.
The body is supported by a skeleton made of spongin, spicules, or both.

6. Chapter 33 Sponges Section 1 Porifera
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Visual Concept

7. Section 1 Porifera
Chapter 33
Structure of a Sponge

8. Chapter 33 Parts of a Sponge Section 1 Porifera
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Visual Concept

9. Chapter 33 Collar Cells Section 1 Porifera
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Visual Concept

10. Feeding and Digestion in Sponges
Section 1 Porifera
Chapter 33
Feeding and Digestion in Sponges
Sponges feed by filtering small organisms and organic matter out of the water that passes through their body. This is called filter feeding.
Nutrients are distributed through the body by amoebocytes, cells which crawl about within the body wall.

11. Feeding Habits of Sponges
Section 1 Porifera
Chapter 33
Feeding Habits of Sponges
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Visual Concept

12. Reproduction in Sponges
Section 1 Porifera
Chapter 33
Reproduction in Sponges
Sponges can reproduce both asexually and sexually.
They reproduce asexually through:
producing buds or gemmules
regeneration of missing parts
They reproduce sexually through the joining of egg and sperm.
Most sponges are hermaphrodites, which can produce both eggs and sperm.

13. Sexual Reproduction in Sponges
Section 1 Porifera
Chapter 33
Sexual Reproduction in Sponges

14. Reproduction in Sponges
Section 1 Porifera
Chapter 33
Reproduction in Sponges
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Visual Concept

15. Chapter 33 Gemmules Section 1 Porifera
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Visual Concept

16. Chapter 33 Objectives Describe the basic body plan of a cnidarian.
Section 2 Cnidaria and Ctenophora
Chapter 33
Objectives
Describe the basic body plan of a cnidarian.
Summarize how cnidarians feed.
Describe the nervous system of cnidarians.
Identify and give examples of the four classes of cnidarians.
Describe the common characteristics of ctenophores.

17. Body Plan of Cnidarians
Section 2 Cnidaria and Ctenophora
Chapter 33
Body Plan of Cnidarians
Animals in the phylum Cnidaria are radially symmetrical aquatic invertebrates that are more complex than the sponges. They have tissues and a few simple organs.
The cnidairan body is either a sessile polyp or a swimming medusa. Some cnidarians alternate between both types during their life cycles.
The body of a cnidarian consists of two cell layers:
an outer epidermis
an inner gastrodermis
The layers are separated by the mesoglea.
The gastrovascular cavity has a single opening (the mouth) surrounded by tentacles.

18. Feeding and Defense in Cnidarians
Section 2 Cnidaria and Ctenophora
Chapter 33
Feeding and Defense in Cnidarians
Cnidarians have cells called cnidocytes.
Each cnidocyte contains a nematocyst.
When a cnidocyte is stimulated, its nematocyst ejects a filament that can paralyze or ensnare prey.
Nervous System in Cnidarians
The cnidarian nervous system is a diffuse web of interconnected nerve cells called a nerve net.

19. Classification of Cnidarians
Section 2 Cnidaria and Ctenophora
Chapter 33
Classification of Cnidarians
The four classes of cnidarians are:
Class Hydrozoa
This class includes Obelia, man-o-war, and the hydra.
Hydrozoans may live as polyps, medusae, or mixed colonies.
Class Cubozoa
This class includes box jellies.
Cubozoans spend most of their lives as medusae.
Class Scyphozoa
This class includes jellyfish.
Scyphozoans spend most of their lives as medusae.
Class Anthozoa
This class includes sea anemones and corals.
Anthozoans live only as polyps.

20. Reproduction in Obelia
Section 2 Cnidaria and Ctenophora
Chapter 33
Reproduction in Obelia

21. Chapter 33 Movement of Hydra Section 2 Cnidaria and Ctenophora
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Visual Concept

22. Reproduction in Hydras
Section 2 Cnidaria and Ctenophora
Chapter 33
Reproduction in Hydras
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Visual Concept

23. Reproduction in Aurelia
Section 2 Cnidaria and Ctenophora
Chapter 33
Reproduction in Aurelia

24. Reproduction in Jellyfish
Section 2 Cnidaria and Ctenophora
Chapter 33
Reproduction in Jellyfish
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Visual Concept

25. Comparing Medusa and Polyp Bodies
Section 2 Cnidaria and Ctenophora
Chapter 33
Comparing Medusa and Polyp Bodies
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Visual Concept

26. Section 2 Cnidaria and Ctenophora
Chapter 33
Coral Reefs

27. Chapter 33 Phylum Ctenophora
Section 2 Cnidaria and Ctenophora
Chapter 33
Phylum Ctenophora
Animals in the phylum Ctenophora are known as ctenophores and often called comb jellies.
Ctenophores move through the water by beating the cilia that occur in eight rows on the outside of their body.
Ctenophores capture prey with a sticky substance secreted by their colloblasts.
An apical organ at one end of the body enables ctenophores to sense their orientation in the water.
Most ctenophores are hermaphroditic.
Many ctenophores have bioluminescence.

28. Two Cnidarian Body Forms
Section 2 Cnidaria and Ctenophora
Chapter 33
Two Cnidarian Body Forms

29. Section 2 Cnidaria and Ctenophora
Chapter 33
Cnidarian Body Plan

30. Exploration of a Cnidarian
Section 2 Cnidaria and Ctenophora
Chapter 33
Exploration of a Cnidarian

31. Development of Cnidarian Embryo
Section 2 Cnidaria and Ctenophora
Chapter 33
Development of Cnidarian Embryo

32. Characteristics of Cnidarians
Section 2 Cnidaria and Ctenophora
Chapter 33
Characteristics of Cnidarians
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Visual Concept

33. Chapter 33 Cnidocyte Section 2 Cnidaria and Ctenophora
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Visual Concept

34. Chapter 33 Types of Cnidarians Section 2 Cnidaria and Ctenophora
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Visual Concept

35. Chapter 33 Multiple Choice
Standardized Test Prep
Multiple Choice
1. Why are spongin and spicules important to a sponge?
A. They digest food.
B. They remove wastes.
C. They provide support.
D. They produce offspring.

36. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
1. Why are spongin and spicules important to a sponge?
A. They digest food.
B. They remove wastes.
C. They provide support.
D. They produce offspring.

37. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
2. Which of the following structures are involved in both feeding and sexual reproduction in sponges?
F. spicules and gemmules
G. amoebocytes and spongin
H. gemmules and choanocytes
J. choanocytes and amoebocytes

38. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
2. Which of the following structures are involved in both feeding and sexual reproduction in sponges?
F. spicules and gemmules
G. amoebocytes and spongin
H. gemmules and choanocytes
J. choanocytes and amoebocytes

39. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
3. Which of the following is not a characteristic of cnidarians?
A. tentacles
B. choanocytes
C. nematocysts
D. gastrovascular cavity

40. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
3. Which of the following is not a characteristic of cnidarians?
A. tentacles
B. choanocytes
C. nematocysts
D. gastrovascular cavity

41. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
4. What do colloblasts do?
F. They produce light.
G. They secrete a sticky substance.
H. They draw water through sponges.
J. They form medusae that live in colonies.

42. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
4. What do colloblasts do?
F. They produce light.
G. They secrete a sticky substance.
H. They draw water through sponges.
J. They form medusae that live in colonies.

43. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
The diagram below illustrates a hydra. Study the diagram to answer the questions that follow.

44. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
5. Identify the substance found at point 3.
A. osculum
B. mesoglea
C. gastrodermis
D. gastrovascular cavity

45. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
5. Identify the substance found at point 3.
A. osculum
B. mesoglea
C. gastrodermis
D. gastrovascular cavity

46. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
6. Which structure is involved in defense?
F. 1
G. 2
H. 3
J. 4

47. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
6. Which structure is involved in defense?
F. 1
G. 2
H. 3
J. 4

48. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
7. Sponge : osculum :: hydra :
A. mouth
B. tentacle
C. nerve net
D. nematocyst

49. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
7. Sponge : osculum :: hydra :
A. mouth
B. tentacle
C. nerve net
D. nematocyst

50. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
The diagram below illustrates a medusa. Study the diagram to answer the question that follows.

51. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
8. In which class is this body form dominant?
F. Cnidaria
G. Hydrozoa
H. Anthozoa
J. Scyphozoa

52. Multiple Choice, continued
Chapter 33
Standardized Test Prep
Multiple Choice, continued
8. In which class is this body form dominant?
F. Cnidaria
G. Hydrozoa
H. Anthozoa
J. Scyphozoa

53. Chapter 33 Short Response
Standardized Test Prep
Short Response
Cnidarians have two tissue layers, which is an important evolutionary advancement.
Describe the tissue layers and general body structure of a typical cnidarian.

54. Short Response, continued
Chapter 33
Standardized Test Prep
Short Response, continued
Cnidarians have two tissue layers, which is an important evolutionary advancement.
Describe the tissue layers and general body structure of a typical cnidarian.
Answer: There are two tissue layers: the epidermis and gastrodermis. Mesoglea lies between these layers. The epidermis has cnidocytes for defense and capturing prey. Digestion occurs in the gastrovascular cavity, which is surrounded by the gastrodermis.

55. Chapter 33 Extended Response
Standardized Test Prep
Extended Response
Base your answers to parts A & B on the information below.
Sponges reproduce asexually in a number of ways.
Part A Describe three forms of asexual reproduction in sponges.
Part B Explain how reproducing asexually is advantageous to sponges.

56. Extended Response, continued
Chapter 33
Standardized Test Prep
Extended Response, continued
Answer:
Part A: Sponges can reproduce sexually or asexually by budding or producing gemmules, which are internal buds with a protective coating and internal food supply. A third way is by regeneration, in which a tiny piece of sponge grows into a new, complete sponge.
Part B: Sponges are sessile and unable to search for mates for sexual reproduction. Reproducing asexually also helps sponges survive certain conditions.