1. Population Ecology Chapter 53 Eric Ribbens Western Illinois University
Questions prepared by
Eric Ribbens Western Illinois University
John Zarnetske Hoosick Falls Central Schools

2. Which of the following sets of measurements is the most useful when studying populations?
gene frequency over time and the ratio of reproductive to nonreproductive individuals
density, dispersion, and demographics of a population
minimum and minimum amounts of precipitation and annual temperature extremes
ratio of predators and the number of immigrants and emigrants
annual precipitation averages and mean annual temperatures
Answer: b

3. Population ecologists are primarily interested in
understanding how biotic and abiotic factors influence the density, distribution, size, and age structure of populations.
the overall vitality of a population of organisms.
how humans affect the size of wild populations of organisms.
studying interactions among populations of organisms that inhabit the same area.
how populations evolve as natural selection acts on heritable variations among individuals and changes in gene frequency.
Answer: a

4. Dispersion patterns tend to be highly dependent on the spatial scale of the observer. For example, football players lined up on the scrimmage line are clumped at the scale of 100 yards but uniformly dispersed at the scale of a meter. An example of animals that are likely to be clumped at a large scale but uniformly distributed at a small scale is
buffalo grazing on a prairie.
bluegills swimming in a northern lake.
ant nests in an abandoned field.
red-winged blackbirds in a cattail marsh.
all of the above.
Answer: e

5. A mark-recapture study would be a good way to find out how many
queens live in a beehive.
cubs that black bears in Minnesota are likely to have.
pine trees live in a forest.
fish live in a lake.
people speed on an interstate.
Answer: d

6. Look at the table in the next slide, a life table for Belding’s ground squirrels. One important thing missing from this table before we can completely understand their population dynamics is
why females live longer than males.
how many offspring females produce each year.
whether the reasons for mortality change as the squirrels get older.
what research technique was used, and whether it affected the squirrels’ behavior.
whether males are promiscuous or form pair-bonds with females.
Answer: b

8. Imagine that a species of fish used to be a broadcast spawner (producing many eggs that then get no subsequent parental care) but has evolved to be a mouth brooder (holding the eggs in the parent’s mouth until they hatch and then caring for the young for a while). We would expect the survivorship curve of this species to shift
from Type I to Type II or III.
from Type II to Type I.
from Type III to Type I or II.
from Type II to Type III.
The survivorship type would vary unpredictably.
Answer: c
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9. “The fundamental idea that evolution accounts for the diversity of life is manifest in a broad range of life histories found in nature.” You know that natural selection keeps genotypes that produce the most surviving offspring and discards genotypes that produce fewer surviving offspring. Therefore, you can predict that species that have evolved semelparity have done so because
semelparous parents produce more offspring if they invest all of their resources in reproduction than they would if they saved enough resources to survive until they can reproduce again.
semelparous parents produce offspring that are more likely to survive than offspring produced by iteroparous parents.
iteroparous parents are less likely to provide parental care than semelparous parents.
semelparous parents and iteroparous parents are equally likely to produce offspring; semelparity evolved for other reasons.
iteroparous parents are more likely to die before they can reproduce than are semelparous parents.
Answer: a

10. The exponential growth model describes the increase in population size of a population that is not constrained by resources or space. The graph shows the elephant population in Kruger National Park, which appears to have been reproducing exponentially from 1900 to From this graph, you can tell that
none of the elephants died.
a female elephant living around was more likely to have a baby than a female elephant living around 1920.
the elephants adapted to the new park conditions around 1955.
the vegetation the elephants eat could support more than 5,000 elephants.
the more elephants there are, the more tourists will visit the park.
Answer: d

11. The logistic model incorporates the idea of K, the carrying capacity, which is the maximum number of individuals the ecosystem can sustain over time. Essential to this idea is the concept that population growth rates are reduced when the population size approaches K. Look at the graphs on the next slide. Both Paramecium and Daphnia have population dynamics that stabilize around K. However, Daphnia overshot their carrying capacity, but Paramecium did not. This is probably because
a) Paramecium are a single-celled organism.
b) Daphnia live in water.
c) the Daphnia had to learn what their carrying capacity was.
d) the Paramecium population had a bigger K (about 800) than Daphnia (about 120).
e) something about Daphnia responds differently to K than Paramecium.
Answer: e

13. From the following graph you can tell that
families in Mexico are still more likely to be bigger than families in Sweden.
more people live in Mexico than in Sweden.
birth rates and death rates do not appear to be correlated.
a Swedish person born in is more likely to be dead than a Mexican person born in 1900.
these populations are probably far away from their carrying capacity.
Answer: a

14. The graph shows the percent increase in the global human population
The graph shows the percent increase in the global human population. There is a sharp dip around 1960, which the legend says is due mainly to a famine in China in which 60 million people died. The graph also predicts that the percent increase is dropping and will continue to drop throughout the 21st century. Which of the following statements is true?
The famine in China and the 21st-century decline are both examples of density-independent factors.
The famine in China and the 21st-century decline are both examples of density-dependent factors.
The famine in China was density-independent, but the 21st-century decline is density dependent.
The famine in China was density-dependent, but the 21st-century decline is density independent.
Because the causes of the famine and the 21st-century decline are different, you cannot tell whether they are density dependent.
Answer: b

15. Most ecologists agree that people should not be using more than 1
Most ecologists agree that people should not be using more than 1.7 ha of resources if they want to be sustainable. People in the United States use an average of 10 ha. This implies that
the ecological footprint concept is flawed.
the United States has more land than other countries do.
U.S. rates of resource consumption are too high.
U.S. people are happier.
U.S. people are less likely to emigrate.
Answer: c