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Campbell Biology : Concepts and Connections

Jane B. Reece, Martha R. Taylor, Eric J. Simon

Chapter 36

Population Ecology - all with Video Answers

Educators

Chapter Questions

10:52

Problem 1

Use this graph of the idealized exponential and logistic growth curves to complete the following.
a. Label the axes and curves on the graph.
b. Give the formula that describes the blue curve.
c. What does the dotted line represent?
d. For each curve, indicate and explain where population growth is the most rapid.
e. Which of these curves best represents global human population growth?
(IMAGE CAN'T COPY)

Dennis Howard
Dennis Howard
Numerade Educator
04:15

Problem 2

The graph below shows the demographic transition for a hypothetical country. Many developed countries that have achieved
a stable population size have undergone a transition similar to this. Answer the following questions concerning this graph.
a. What does the blue line represent? The red line?
b. This diagram has been divided into four sections. Describe what is happening in each section.
c. In which section(s) is the population size stable?
d. In which section is the population growth rate the highest?
(GRAPH CAN'T COPY)

Dennis Howard
Dennis Howard
Numerade Educator
01:53

Problem 3

After seeds have sprouted, gardeners often pull up some of the seedlings so that only a few grow to maturity. How does this practice help produce the best yield?
a. by increasing $K$
b. by decreasing $r$
c. by reducing intraspecific competition
d. by adding a density-independent factor to the environment

Dennis Howard
Dennis Howard
Numerade Educator
03:09

Problem 4

To figure out the human population density of your community, you would need to know the number of people living there and
a. the land area in which they live.
b. the birth rate of the population.
c. the dispersion pattern of the population.
d. the carrying capacity.

Dennis Howard
Dennis Howard
Numerade Educator
05:47

Problem 5

The term $(K-N) / K$
a. is the carrying capacity for a population.
b. is greatest when $K$ is very large.
c. is zero when population size equals carrying capacity.
d. increases in value as $N$ approaches $K$

Dennis Howard
Dennis Howard
Numerade Educator
01:07

Problem 6

With regard to its rate of growth, a population that is growing logistically
a. grows fastest when density is lowest.
b. has a high intrinsic rate of increase.
c. grows fastest at an intermediate population density.
d. grows fastest as it approaches carrying capacity.

Priya Manhas
Priya Manhas
Numerade Educator
06:58

Problem 7

Which of the following represents a demographic transition?
a. A population switches from exponential to logistic growth.
b. A population reaches zero population growth when the birth rate drops to zero.
c. There are equal numbers of individuals in all age-groups.
d. A population switches from high birth and death rates to low birth and death rates.

Noah Boudrie
Noah Boudrie
Numerade Educator
06:32

Problem 8

Skyrocketing growth of the human population appears to be mainly a result of
a. a drop in death rate due to sanitation and health care.
b. better nutrition boosting the birth rate.
c. the concentration of humans in cities.
d. social changes that make it desirable to have more children.

Noah Boudrie
Noah Boudrie
Numerade Educator
07:35

Problem 9

According to data on ecological footprints,
a. the carrying capacity of the world is 10 billion.
b. the current demand on global resources by industrialized countries is less than the resources available in those countries.
c. the ecological footprint of the United States is more than twice the world average.
d. nations with the largest ecological footprints have the fastest population growth rates.

Noah Boudrie
Noah Boudrie
Numerade Educator
03:14

Problem 10

What are some factors that might have a density-dependent limiting effect on population growth?

Dennis Howard
Dennis Howard
Numerade Educator
06:30

Problem 11

What is survivorship? What does a survivorship curve show? Explain what the three survivorship curves tell us about humans, squirrels, and oysters.

Noah Boudrie
Noah Boudrie
Numerade Educator
02:40

Problem 12

Describe the factors that might produce the following three types of dispersion patterns in populations. (FIGURE CANT COPY)

Dennis Howard
Dennis Howard
Numerade Educator
08:57

Problem 13

The mountain gorilla, spotted owl, giant panda, snow leopard, and grizzly bear are all endangered by human encroachment on their environments. Another thing these animals have in common is that they all have $K$ -selected life history traits. Why might they be more easily endangered than animals with $r$ -selected life history traits? What general type of survivor ship curve would you expect these species to exhibit? Explain your answer.

Caroline Jones
Caroline Jones
Numerade Educator
02:37

Problem 14

Another hypothesis for snowshoe hare population cycles proposes that they are caused by sunspot activity. According to this hypothesis, sunspot activity affects the chemicals present in the plants eaten by hares, which in turn affects the quality of the food. What testable predictions are generated by this hypothesis?

Dennis Howard
Dennis Howard
Numerade Educator
04:37

Problem 15

Many people regard the rapid population growth of developing countries as our most serious environmental problem. Others think that the growth of developed countries, though slower, is actually a greater threat to the environment. What kinds of environmental problems result from population growth in (a) developing countries and (b) developed countries? Which do you think is the greater threat? Why?

Dennis Howard
Dennis Howard
Numerade Educator