1. For each pair of terms, explain how the meanings of the terms differ.
a. tegument and cuticle b. primary host and intermediate host c. schistosomiasis and trichinosis d. anus and cloaca e. scolex and mastax
2. Choose the term that does not belong in the following group, and explain why it does not belong: eyespot, flame cell, gastrovascular cavity, and proglottid.
3. Explain the relationship between proglottid and cyst.
4. Word Roots and Origins The word part roti-means "wheel," and the suffix -fera means "bearer." Using this information, explain why Rotifera is a good name for the phylum of organisms it describes.
Understanding Key Concepts
5. Explain how a flatworm can survive without a circulatory system or a respiratory system.
6. Describe the nervous system of a planarian.
7. Summarize reproduction in planarians.
8. Sequence the following steps in the schistosome life cycle in the correct order, beginning with the first step after sexual reproduction.
a. Tailed larvae swim through the water.
b. Ciliated larvae swim through the water.
c. Larvae penetrate the skin of a human.
d. Larvae reproduce asexually in the intermediate host.
e. Larvae burrow into a snail.
f. Larvae enter a blood vessel and develop into adults.
g. Fertilized eggs leave the primary host in the feces or urine.
9. Compare a primary host to an intermediate host.
10. Identify some adaptations of flukes to a parasitic way of life.
11. Explain how tapeworms are specialized for a parasitic way of life.
12. Relate how a person can avoid becoming infected by a beef tapeworm.
13. Compare the body plan of a nematode to that of a flatworm.
14. Name some features shared by roundworms and rotifers.
16. JX CONCEPT MAPPING Use the following □ □ □ terms to create a concept map that shows the major characteristics of the phylum Nematoda: roundworms, pseudocoelomates, digestive tract, cuticle, free-living, water, parasites, separate sexes, and eggs.
17. Applying Information The Aswan High Dam across the Nile River in Egypt was completed in 1970. The dam was built to increase the supply of irrigation water, control major flooding, and provide a source of hydroelectric power. Since the dam was built, however, there has been an increase in the incidence of schistosomiasis in the region. Why do you think this has happened?
18. Distinguishing Relevant Information A person infected with a tapeworm may show symptoms such as tiredness, loss of weight, and anemia, which could indicate any number of diseases. How might a doctor be certain that the symptoms are caused by a tapeworm?
19. Recognizing Relationships Hookworm infections are extremely common in China, where rice is grown in paddies that are periodically flooded. Considering what you know about how hookworms invade the human body, why do you think hookworm infections are so common in this part of the world?
20. Analyzing Patterns Some rotifers can survive being dried out for as long as four years. When they are placed in water again, they revive. For what kind of environment might this characteristic be adaptive?
21. Interpreting Graphics Identify the animal in the photograph below. Give reasons for your choice.
<¿9 Standardized Test Preparation
DIRECTIONS: Choose the letter that best answers the question.
1. What does a planarian use its pharynx for?
D. to respond to light
2. Where do blood flukes of the genus Schistosoma reproduce asexually?
F. in water
G. inside a snail
H. inside a cow's intestine
J. inside a human's blood vessels
3. What does a tapeworm use its scolex for?
A. to reproduce
B. to attach itself to its host
C. to eliminate excess water
D. to force food into its mouth
4. Which of the following is true of most rotifers?
F. They are parasitic.
G. They live in the soil.
H. They feed with the help of cilia.
INTERPRETING GRAPHICS: The figure below shows the internal structure of a planarian of the genus Dugesia. Use the figure to answer the questions that follow.
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