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Exam 15: Conserving Biodiversity: Community and Ecosystem Ecology

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Question 1

Multiple Choice

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Although most biologists believe that many species are becoming extinct each year because of the activities of humans, relatively few species actually appear on compiled lists of extinct species. What is one reason why so few species are listed as extinct?

A) Many species are unknown to science and go extinct before they've been described.
B) There really aren't that many species that have become extinct.
C) Many species aren't listed because they aren't considered important.
D) Only extinctions that are naturally caused are listed.

E) A) and D)
F) All of the above

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Question 2

Multiple Choice

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Which organism comprises the largest and bottom base level of the trophic pyramid?

A) decomposers
B) producers
C) primary consumers
D) secondary consumers

E) None of the above
F) B) and D)

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B

Question 3

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Ants from the genus Pseudomyrmex live in bull's horn acacia trees, Acacia cornigera. The ants will attack any predators of the tree. In return, the ants live protected in the thorns of the tree and eat the nectar and protein-rich secretions of the tree. What term describes this relationship?

What role would an owl that eats a seed-eating mouse perform in a food chain?

Why is the preservation of ancestor species, such as Mexican teosinte (Zea diploperennis) , important in the context of human welfare?

Which animal is critically endangered in the United States?

In order to be considered extinct, a species can't be found

Which organism can be considered a predator?

Approximately what percentage of the species that have ever existed on Earth are represented by the estimated 10 million species that exist today?

How many species normally go extinct each year, as estimated by scientists?

What process recycles molecules from inorganic areas to living parts of an ecosystem?

Which threat to biodiversity isn't directly due to humans?

What process resulted in the loss of heath hens in North America?

What is the role a species plays in an ecosystem?

What describes the greater fitness of individuals who carry one copy of the sickle-cell allele in areas where malaria is common?

Which factor presents the greatest threat to biodiversity?

A researcher returns from the Amazon River with 10 individuals of a species of fish and establishes a small breeding colony in her laboratory. She maintains the colony for several years (many fish generations) , always maintaining the number of adult fish between 10 and 30. She notices that as generations of fish are bred, the reproductive rate decreases. What is the most likely reason for this?

Approximately 200 of the 300 native species of fish in Lake Victoria haven't been observed since the 1960s and are therefore probably extinct. Using the estimate of the background extinction rate, how many species of Lake Victoria fish would one expect to have naturally become extinct during the last 50 years?

During the last decade, the U.S. Fish and Wildlife Service has worked to reestablish the critically endangered California condor in its last stronghold, the mountains of southern California. Recently, the service has also tried to establish a second population in the Grand Canyon region of Arizona. Why would the Fish and Wildlife Service consider it a high priority to establish two populations that are geographically distant from each other?

Why is a woman more susceptible to vaginal yeast infections when taking antibiotics?