Q: A conservation biologist is studying a population of grizzly bears in Yellowstone National Park. If there are 40 breeding females and 10 breeding males, what is the effective population size ($$N_e$$)? Use the formula $$N_e = \frac{4N_f N_m}{N_f + N_m}.$$

$$N_e = \frac{4 \times 40 \times 10}{40 + 10} = \frac{1600}{50} = 32$$

Question 1

Which of the following best describes the concept of ecosystem services?

Accepted Answer

The processes by which natural ecosystems help sustain human life, such as pollination, water purification, and climate regulation.

Question 2

A conservation biologist is studying a population of grizzly bears in Yellowstone National Park. If there are 40 breeding females and 10 breeding males, what is the effective population size ($$N_e$$)? Use the formula $$N_e = \frac{4N_f N_m}{N_f + N_m}.$$

Accepted Answer

$$N_e = \frac{4 	imes 40 	imes 10}{40 + 10} = \frac{1600}{50} = 32$$

Question 3

Which of the following is NOT a major threat to biodiversity as identified in conservation biology?

Accepted Answer

Natural selection

Question 4

A population of birds is declining due to inbreeding and genetic drift. This situation is best described as:

Accepted Answer

An extinction vortex

Question 5

Which of the following scenarios illustrates biological magnification?

Accepted Answer

Herring gulls in the Great Lakes lay eggs with PCB concentrations 5,000 times greater than in phytoplankton.

Question 6

Which community is more diverse: Community 1 (A: 25%, B: 25%, C: 25%, D: 25%) or Community 2 (A: 80%, B: 5%, C: 5%, D: 10%)? Why?

Accepted Answer

Community 1, because it has greater evenness among species.

Question 7

Which of the following best explains why estimates of the number of species on Earth vary so widely?

Accepted Answer

Many species, especially in tropical rainforests and deep sea environments, remain undiscovered.

Question 8

A conservation biologist must decide between preserving one large patch of habitat or several small patches. Which is a likely advantage of preserving several small patches?

Accepted Answer

They allow protection of different types of habitat that may house different species.

Question 9

Which of the following is an example of an ecosystem service provided by biodiversity?

Accepted Answer

Pollination of crops by bees

Question 10

Which of the following statements about endangered and threatened species is correct?

Accepted Answer

Endangered species are at risk of extinction throughout all or much of their range.

Question 11

Which of the following is a consequence of habitat fragmentation?

Accepted Answer

Some species adapted to forest interior are severely affected by edges and need large patches.

Question 12

A river drains fertilizers into the ocean, causing phytoplankton blooms. What is the likely consequence for aquatic life?

Accepted Answer

Decomposition of blooms causes anoxic 'dead zones' where aquatic life cannot survive.

Question 13

Which of the following is a real-world example of an introduced species causing biodiversity loss?

Accepted Answer

The brown tree snake in Guam led to the extinction of several bird and lizard species.

Question 14

Which equation is used to estimate the effective population size ($$N_e) in $$conservation biology?

Accepted Answer

$$N_e = \frac{4N_f N_m}{N_f + N_m}$$

Question 15

Which of the following is a reason why large organisms with low reproductive rates are more susceptible to overharvesting?

Accepted Answer

They cannot quickly recover their population numbers after being harvested.

Question 16

Which of the following best describes the role of DNA analysis in conservation biology?

Accepted Answer

It helps identify the source of illegally obtained animal products.

Question 17

Which of the following is a direct effect of burning fossil fuels on global ecosystems?

Accepted Answer

Release of CO$$_2$$ into the atmosphere, contributing to climate change.

Question 18

Which of the following is a critical consideration when reintroducing cloned or genetically assisted species to the wild?

Accepted Answer

Whether suitable habitat exists for their survival.

Question 19

Which of the following is a take-home message from conservation biology?

Accepted Answer

Healthy ecosystems are important for human health.

Conservation Biology: Biodiversity, Threats, and Strategies

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