Populations Practice
Population Density
#1. What is the population density of 10 easter bunnies spread out over 50 m2?
#2. What is the population density of 17 daisies over an area of 2m2?
#3. If you have a population of 67 mice in a field with a total population density of 9.8 mice/m2, how big is the field?
#4. If there are 22 fish in a tank filled with 3m3 of water, what is the population density?
#5. Estimate the size of a population of apple trees spread over a field 78m2 if there are 4.1 trees/m2.
#6. If there are 67 cats in a 3 block area of 56m2, how many cats can we expect to find over an area of 78m2?
Population Growth
#1. What is the population growth of a community of 1000 that experiences 50 births, 45 deaths, 20 immigrations and 5
emigrations?
#2. Calculate the population growth of a community that has 46 births, 4 immigrations, 34 deaths and 35 emigrations.
#3. A community of 9780 has 19 deaths, 3 immigrations, 88 births and 44 emigrations. What is the change in
population growth?
#4. Calculate the population growth of a community that experiences no births, 3 deaths and 78 immigrations.
Percent Population Growth
#1. What is the percent growth of a community of 1009 that experiences 3 deaths and 4 emigrations?
#2. Calculate the percent growth of a community of 876 that has a +3.4 person change in population.
#3. Calculate the percent growth of a community of 44 that experiences 2 deaths and 5 births in addition to an 8 person
immigration.
Per Capita Growth Rate
#1. What is the per capita growth rate of a population who grows to 90 000 from 60 000 in 2 years?
#2. Calculate the per capita growth rate of a deer population that grows from 4500 to 6732.
#3. What is the per capita growth rate of an elk population that grows to 9800 from 9780 in 2 months?
#4. A population of cougars that shrinks to 887 from 900 in 2 months due to a lack of resources and overabundance of
competition. What is the per capita growth rate?
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K – selected species vs. r-selected species
#1. List the six factors that affect biotic potential.
#2. List the ONE characteristic that allows you to differentiate between K-selected and r-selected species.
#3. What is K?
#4. What is r?
#5. Draw a J curve.
#6. Draw an S curve.
Use the following information to answer the next three questions.
A sheep farm in central Alberta is located on a plot of land 3.00 km by 2.00 km. There are
858 female sheep and 42 male sheep on the farm. The farmer has constructed shelters for the
sheep and provides them with food and water to supplement the graze that is naturally
available.
1. Which statement describes the likely effect of the intervention by the farmer on the sheep
population growth rate (r)?
A.
r would be negative because b would increase and d would decrease.
B.
r would be negative because b would decrease and d would increase.
C.
r would be positive because b would increase and d would decrease.
D.
r would be positive because b would decrease and d would increase.
Numerical Response
05. Calculate the population density (sheep/km2) of the sheep on this farm.
(Record your answer rounded to three significant digits in the numerical-response section of the
answer sheet.)
Answer: _______
2. The sheep liver fluke is an organism that lives in the intestines, liver, brain, and lungs of sheep
and causes tissue damage in these organs. Which statement best describes the likely effect of a
severe infestation of sheep liver flukes on a sheep population?
A. Commensalism would reduce the carrying capacity of the sheep population.
B. Parasitism would reduce the carrying capacity of the sheep population.
C. Commensalism would reduce the density of the sheep population.
D. Parasitism would reduce the density of the sheep population.
2
Use the following information to answer the next two questions.
Populations of Yeast and Paramecium
A suspension of yeast cells was added to a sucrose solution (nutrient medium) and incubated
at 25°C for 16 days. On the fifth day, a small culture of the ciliate Paramecium was added.
Each day, a 10 mL sample was withdrawn, the number of organisms present was
determined, and the sample was returned to the mixture. The data collected were recorded
on the following graph.
3. The two factors that were likely responsible for the fluctuations in the population of yeast from
day 4 to day 16 were
A. predation and limited food supply
B. temperature intolerance and predation
C. limited food supply and overcrowding
D. overcrowding and temperature intolerance
4. A likely cause of the change in the yeast population from day 7 to day 9 was
A. an increase in nutrient concentration
B. an increase in environmental resistance
C. a decrease in the Paramecium population
D. a decrease in population density of the yeast
3
Use the following information to answer the next question.
Hypothetical Population Growth Curves
Numerical Response
06. Select the set of four numbers from the graph that correctly completes the
following statement.
Plotting uncontrolled, rapid population growth results in the curve labelled ____.
However, the effect of environmental resistance, labelled ____ normally limits
growth, resulting in the curve labelled ____. The population size becomes stable
when the carrying capacity, labelled ____, is reached.
(Record your four-digit answer in the numerical-response section of the answer sheet.)
Answer: _______
4
Use the following information to answer the next two questions.
Sickle cell anemia is caused by an allele (HbS) that codes for abnormal hemoglobin-S.
Heterozygous individuals produce both normal hemoglobin and a small percentage of
hemoglobin-S. These individuals are more resistant to malaria than individuals who are
homozygous for the allele for normal hemoglobin (Hb A). In areas where malaria is common,
the frequency of the allele for hemoglobin-S is higher than in areas where malaria is
uncommon.
Malaria is a sometimes fatal disease caused by the micro-organism Plasmodium falciparum,
which is injected by certain mosquitoes into the bloodstream of humans. In Africa, the
frequency of the HbS allele relates directly to the presence of malaria-causing organisms. In
western Africa, the frequency of the HbS allele is 0.15; in central Africa, the frequency is
0.10; and in southern Africa, the frequency is 0.05.
9. The relationship between humans and Plasmodium falciparum is called
A.
B.
C.
D.
parasitism
mutualism
competition
commensalism
Use the following information to answer the next question.
C.F.M. Synnerton, a naturalist in Zimbabwe, studied how eyespots on the wings of
butterflies protected the butterflies from predation by sparrows. By moving its wings, the
butterfly makes the eyespots resemble the eyes of an owl, a natural predator of sparrows.
10. The presence of eyespots on the wings of butterflies is an example of
A.
B.
C.
D.
mimicry
mutualism
camouflage
competition
Use the following information to answer the next question.
Some grey whales have barnacles living on their backs. As the whales move from one
location to another, the barnacles are exposed to new sources of their food, plankton. Whales
are unaffected by the presence of the barnacles.
11. The relationship between the barnacles and the whales is one of
A.
B.
C.
D.
predation
parasitism
mutualism
commensalism
5
Use the following information to answer the next two questions.
The Changes in a Daphnia Population Over Time
The graph represents a population of Daphnia (water fleas) cultured in a stable nutritional
environment.
—from Campbell
12. The region labelled X on the graph represents
A.
B.
C.
D.
exponential growth
the carrying capacity
the establishment phase
environmental resistance
Numerical Response
08. The density of Daphnia on day 80 is ________/mL.
(Record your answer rounded to two decimal places in the numerical-response section of the
answer sheet.)
Answer: __________
6
Use the following information to answer the next five questions.
From 1968 to 1990, the population of snow geese nesting near Churchill, Manitoba, increased
from about 2 000 pairs (4 000 individuals) to about 22 500 pairs (45 000 individuals) with a
nesting density of around 1 000 nests per square mile. Snow geese winter along the coasts of
Texas and Louisiana. Prior to 1960, marshes along these coasts provided the main food
sources (reeds, roots, and tubers) for the geese. Destruction of these marshes and increased
crop production of rice, corn, and soybeans has occurred since that time. The stubble from
these crops and spilled grains are easily obtained food sources for the snow geese. Reduction
in hunting and greatly increased food supplies from cultivation near their wintering ground
has cut mortality rates of snow geese in half over this period.
The high nesting density of the snow geese has left little foraging or nesting space for other
species of birds, and a decline in several duck species and shore birds has been observed.
Simultaneously, intensive foraging by the snow geese erodes and dries out patches of Arctic
soil, reduces regrowth of grasses and sedges, and greatly increases soil salinity.
—from Brodie, 1997
Numerical Response
07. Based on the information provided, what is the per capita growth rate of the snow
goose population between 1968 and 1990?
(Record your answer rounded to one decimal place in the numerical-response section on the
answer sheet.)
Answer: __________
13. Prior to 1960, the winter food sources in the marshes controlled the growth of the snow goose
population. The available supply of reeds, roots, and tubers in the marshes was
A.
B.
C.
D.
an example of a community of climax species
an example of a community of pioneer species
a density-dependent limiting factor for snow geese
a density-independent limiting factor for snow geese
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14. Given a further increase in the snow goose population, in the Churchill, Manitoba nesting area
A.
B.
C.
D.
interspecific competition will increase because of decreased species diversity
interspecific competition will increase and intraspecific competition will decrease
intraspecific competition will increase because available food supplies are decreasing
intraspecific competition will decrease because fewer snow geese will be able to find nesting
sites
15. To preserve the diversity of this ecosystem, the first logical human intervention would be to
A.
B.
C.
D.
extend the hunting season and increase collection of snow goose eggs
replant or reseed grasses and sedges depleted by snow goose foraging
reintroduce the duck species and shore bird species that have disappeared from the coastal
marshes
prevent soil erosion by introducing plant species adapted to high salinity in order to anchor
the top soil
16. Based on the information provided, it would be reasonable to conclude that the snow goose
population
A.
B.
C.
D.
has increased its biotic potential
has a higher mortality than natality rate
is in the growth phase and environmental resistance is increasing
has reached the carrying capacity of the ecosystem and environmental resistance is
decreasing
Use the following information to answer the next question.
Examples of Ecological Relationships
1Tropical acacia trees are hosts to a particular species of ants. The ants are provided with
shelter and nutrients from the trees. The trees are protected from other predatory insects by
the ants.
2 The protozoan Opalina ranarum lives in the digestive tract of some frogs and obtains
nutrients in this way without harming the frog.
3 The protozoan Plasmodium is the cause of malaria. Plasmodium lives in the bloodstream of
humans and reproduces inside red blood cells causing the red blood cells to burst.
Numerical Response
08. Match the ecological relationships, as numbered above, with the types of symbiosis
given below.
(Record your three-digit answer in the numerical-response section on the answer sheet.)
Ecological Relationship: __________
__________
Type of Symbiosis: Commensalism Mutualism
__________
Parasitism
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Populations Practice Answers
Population Density:
#1. 0.2 bunnies/m2
#2. 8.5 daisies/m2
#3. 6.8 m2
#4. 7.3 fish/m3
#5. 319.8 trees
#6. 93.3 cats
Population Growth:
#1. 20
#2. -19
#3. 28
#4. 75
Percent Population Growth:
#1. -0.69%
#2. 0.39%
#3. 25%
Per Capita Growth Rate:
#1. 0.5
#2. 0.50
#3. 0.002
#4. -0.015
K-selected species vs. r-selected species:
#1. Age of onset of sexual maturity, gender ratio, estrous cycles, mate availability, litter/clutch size,
fecundity.
#2. Young require parental care
#3. Carrying capacity
#4. Biotic potential
#5.
#6.
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Diploma Practice Answers
1. C
NR#5
150
2. D
3. A
4. C
NR#6
2,4,5,3
9. A
10. A
11. D
12. A
NR#8
NR#7
0.60
10.3
13. C
14. C
15. A
16. C
NR#8
2,1,3
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