Campbell Biology

Lisa A. Urry

Chapter 53

Population Ecology - all with Video Answers

Educators

Chapter Questions

Problem 1

Level 1: Knowledge/Comprehension
Population ecologists follow the fate of same-age
cohorts to
(A) determine a population's carrying capacity.
(B) determine the birth rate and death rate of
each group in a population.
(C) determine if a population is regulated by
density-dependent processes.
(D) determine the factors that affect the size of a population.

Rikhil Makwana

Rikhil Makwana

Numerade Educator

Problem 2

Level 1: Knowledge/Comprehension
A population's carrying capacity
(A) may change as environmental conditions change.
(B) can be accurately calculated using the logistic growth model.
(C) increases as the per capita population growth rate decreases.
(D) can never be exceeded.

Rikhil Makwana

Numerade Educator

Problem 3

Level 1: Knowledge/Comprehension
Scientific study of the population cycles of the snowshoe hare
and its predator, the lynx has revealed that
(A) predation is the dominant factor affecting prey population
cycling.
(B) hares and lynx are so mutually dependent that each species
cannot survive without the other.
(C) both hare and lynx population sizes are affected mainly by
abiotic factors.
(D) the hare population is $r$ -selected and the lynx population
is $K$ -selected.

Rikhil Makwana

Numerade Educator

Problem 4

Level 1: Knowledge/Comprehension
Analyzing ecological footprints reveals that
(A) Earth's carrying capacity would increase if per capita meat
consumption increased.
(B) current demand by industrialized countries for resources
is much smaller than the ecological footprint of those
countries.
(C) it is not possible for technological improvements to
increase Earth's carrying capacity for humans.
(D) the ecological footprint of the United States is large because
per capita resource use is high.

Rikhil Makwana

Numerade Educator

Problem 5

Level 1: Knowledge/Comprehension
Based on current growth rates, Earth's human population in
2019 will be closest to
(A) 2.5 million.
(B) 4.5 billion.
(C) 7.5 billion.
(D) 10.5 billion.

Rikhil Makwana

Numerade Educator

Problem 6

Level $2 :$ Application/Analysis
The observation that members of a population are uniformly
distributed suggests that
(A) resources are distributed unevenly.
(B) the members of the population are competing for access to
a resource.
(C) the members of the population are neither attracted to nor
repelled by one another.
(D) the density of the population is low.

Rikhil Makwana

Numerade Educator

Problem 7

Level $2 :$ Application/Analysis
According to the logistic growth equation
$$\frac{d N}{d t}=r N \frac{(K-N)}{K}$$
(A) the number of individuals added per unit time is greatest
when $N$ is close to zero.
(B) the per capita population growth rate increases as $N$
approaches $K .$
(C) population growth is zero when $N$ equals $K$ .
(D) the population grows exponentially when $K$ is small.

Rikhil Makwana

Numerade Educator

Problem 8

Level $2 :$ Application/Analysis
During exponential growth, a population always
(A) has a constant per capita population growth rate.
(B) quickly reaches its carrying capacity.
(C) cycles through time.
(D) loses some individuals to emigration.

Rikhil Makwana

Numerade Educator

Problem 9

Level $2 :$ Application/Analysis
Which of the following statements about human populations
in industrialized countries is incorrect?
(A) Birth rates and death rates are high.
(B) Average family size is relatively small.
(C) The population has undergone the demographic
transition.
(D) The survivorship curve is Type I.

Rikhil Makwana

Numerade Educator

Problem 10

Level 3: Synthesis/Evaluation
INTERPRET THE DATA To estimate which age cohort in a
population of females produces the most female offspring, you
need information about the number of offspring produced per
capita within that cohort and the number of individuals alive
in the cohort. Make this estimate for Belding's ground squirrels by multiplying the number of females allve at the start of the
year (column 2 in Table 53.1 by the average number of female
offspring produced per female (column 5 in Table 53.1). Draw a
bar graph with female age in years on the $x$ -axis $(0-1,1-2,$ and so on) and total number of female offspring produced for each
age cohort on the $y$ -axis. Which cohort of female Belding's
ground squirrels produces the most female young?

Rikhil Makwana

Numerade Educator

Problem 11

Level 3: Synthesis/Evaluation
EVOLUTION CONNECTION Contrast the selective pressures
operating in high-density populations (those near the carrying
capacity, $K$ ) versus low-density populations.

Rikhil Makwana

Numerade Educator

Problem 12

Level 3: Synthesis/Evaluation
SCIENTIFIC INQUIRY You are testing the hypothesis that
increased population density of a particular plant species
increases the rate at which a pathogenic fungus infects
the plant. Because the fungus causes visible scars on the leaves, you can easily determine whether a plant is infected.
Design an experiment to test your hypothesis. Describe your
experimental and control groups, how you would collect data,
and what results you would see if your hypothesis is correct.

Rikhil Makwana

Numerade Educator

Problem 13

Level 3: Synthesis/Evaluation
SCIENCE, TECHNOLOGY, AND SOCIETY Some people regard
the rapid population growth of less industrialized countries as
our most serious environmental problem. Others think that the
population growth in industrialized countries, though smaller, is actually a greater environmental threat. What problems result
from population growth in (a) less industrialized countries
and (b) industrialized nations? Which do you think is a greater
threat, and why?

Rikhil Makwana

Numerade Educator

Problem 14

Level 3: Synthesis/Evaluation
WRITE ABOUT A THEME: INTERACTIONS In a short essay
$(100-150$ words), identify the factor or factors in Figure 53.18
that you think may ultimately be most important for density-
dependent population regulation in humans, and explain
your reasoning.

Rikhil Makwana

Numerade Educator

Problem 15

Level 3: Synthesis/Evaluation
SYNTHESIZE YOUR KNOWLEDGE
Locusts (grasshoppers in the family Acrididae) undergo cyclic
population outbreaks, leading to massive swarms such as
this one in the Canary Islands, off the west coast of Africa.
Of the mechanisms of density-dependent regulation shown
in Figure 53.18 , choose the two that you think most apply to
locust swarms, and explain why.

Rikhil Makwana

Numerade Educator