Biology: Concepts and Investigations

Marielle Hoefnagels

Chapter 37

Populations - all with Video Answers

Educators

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Chapter Questions

Problem 1

List some of the ways you have interacted with your surroundings today. Categorize each item on your list as a population-, community-,or ecosystem-level interaction.

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Christie Gilbert

Numerade Educator

Problem 2

Chapter 39 describes biomes, the major types of ecosystems. Pick a biome and discuss a community that might be found in that biome. What populations may be included in the community you selected?

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Christie Gilbert

Numerade Educator

Problem 3

Describe the difference between population density and distribution. Why aren't organisms always distributed evenly throughout their habitat?

Courtney Burson

Courtney Burson

Numerade Educator

Problem 4

Why might an ecologist be interested in studying population dynamics?

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Christie Gilbert

Numerade Educator

Problem 5

Calculate the anticipated size of the rotifer population in figure 37.6 after 21 days. Explain your answer.

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Christie Gilbert

Numerade Educator

Problem 6

Refer to the logistic model of population growth shown in figure 37.8 What would be the growth rate $(G)$ of the population if the population size $(N)$ equaled the carrying capacity $(K) ?$ Explain your answer

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Christie Gilbert

Numerade Educator

Problem 7

Suppose that in a population with an equilibrium life history, $60 \%$ of individuals are younger than reproductive age. Is the population likely to grow, remain stable, or decline? Why? Why might this question not apply to a population with an opportunistic life history?

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Christie Gilbert

Numerade Educator

Problem 8

Define the following terms: per capita rate of increase, environmental resistance, and carrying capacity.

Courtney Burson

Courtney Burson

Numerade Educator

Problem 9

Use the Internet to find a species that is growing out of control and a species that is endangered. Compare their birth rates, death rates, and other factors that are leading to the differences in the populations' fates. What techniques do researchers use to study each species?

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Christie Gilbert

Numerade Educator

Problem 10

Cite three recent environmental upheavals that may have had a density-independent influence on wildlife populations.

Courtney Burson

Courtney Burson

Numerade Educator

Problem 11

Some animal behaviors seem at odds with survival and reproduction. For example, when food is scarce, a female scorpion may consume her offspring. In addition, section 35.7 describes a male spider that offers his own body for his mate to consume. Explain each of these behaviors in terms of the trade-offs described in section 37.4A.

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Christie Gilbert

Numerade Educator

Problem 12

Distinguish between opportunistic and equilibrium life histories, and give an example of an organism with each type of life history.

CG

Christie Gilbert

Numerade Educator

Problem 13

Consult the websites for the U.S. Census and $C I A$ World Factbook. What sorts of demographic information do these two sites compile? Why might it be important to understand human population trends within the United States and in the rest of the world?

Courtney Burson

Courtney Burson

Numerade Educator

Problem 14

What is the relationship between the human population and the ecological footprint? Why does the ecological footprint vary around the world? Overall, humans are using many resources at a faster rate than they can be replenished. What actions would be necessary to reduce humanity's ecological footprint to a sustainable level?

Courtney Burson

Courtney Burson

Numerade Educator

Problem 15

Search the Internet for an ecological footprint calculator. What is your ecological footprint? What can you do to reduce the size of your footprint?

CG

Christie Gilbert

Numerade Educator