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Biology 30
Unit D
Unit D Exam
Chapters 21, 22, 23
Name: __________________
Date: __________________
Multiple Choice: Read the question carefully and choose the best answer possible.
1. Which of the following is true?
a. Both individuals and populations evolve.
b. Individuals evolve but species do not.
c. Populations evolve but species do not
d. Populations evolve but individuals do not.
In a population of snakes, 216 are RR with yellow stripes, 288 are Rr with yellow
stripes, and 96 are rr with red stripes.
2. What are the population allele frequencies?
a. R=0.4, r = 0.6
b. R=0.6, r = 0.4
c. R=0.72, r = 0.48
d. R=0.84, r = 0.16
3. Does the population of snakes described in question appear to be in Hardy
Weinberg equilibrium?
a. Yes; the allele frequency will not change in the next generation.
b. No; the allele frequency will change in the next generation.
c. Yes; the allele frequency is changing over time
d. No; at equilibrium, the frequency of R will equal the frequency of r.
4. Which of the following is not a property of the Hardy Weinberg principle?
a. Mates are chosen at random.
b. There is migration in the population.
c. There are not net mutations.
d. There is no natural selection.
5. In randomly mating populations of kangaroo rats, one out of every 100 rats
has stunted legs, which is a recessive trait. Determine the percentage of
genotypes that are heterozygous for this trait.
a. 81%
b. 50%
c. 18%
d. 1%
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6. The founder effect occurs when which of the following takes place?
a. A geographic barrier is removed.
b. Small populations become isolated.
c. A large population is able to move into a new environment.
d. There is gene flow between two previously separated populations.
7. Which of the following is true in small populations?
a. Chance leads to increased homozygosity.
b. Alleles have little chance of becoming fixed in the population.
c. Genetic drift is rare and has little influence over population change.
d. Bottlenecks result in an increase in genetic diversity in the
populations.
8. A change in allele frequencies related to chance events that are often seen in
small populations is called
a. Gene flow
b. Mutation
c. Founder effect
d. Genetic drift
9. Rats tend to be found next to barns and silos but not in the middle of fields.
Which of the following best describes the population dispersion of rats?
a. Clumped
b. Uniform
c. Random
d. Scattered
10. Which of the following is an example of a closed population?
a. A group of frogs living in a marsh in British Columbia
b. A herd of dairy cows living on an Alberta farm
c. A pride of lions living in the African savannah
d. A flock of geese in a large field.
11. Population growth in an open population can be calculated using the equation:
a. (natality + mortality) – (immigration + emigration)
b. (natality + immigration) – (mortality + emigration)
c. (natality + emigration) – (mortality + immigration)
d. (mortality + emigration) – (natality + immigration)
12. What is the term for the number of offspring a population could produce if no
limits were placed on it?
a. Natality
b. A density-independent limiting factor
c. Biotic potential
d. A density-dependent limiting factor
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13. A population of swift fox in southern Alberta contains 250 individuals. During
the years there are 46 births, 18 deaths, 12 immigrations and 7 emigrations.
The per capita growth that year is:
a. 13.2%
b. 18.0%
c. 9.2%
d. 33.2%
14. When does stable population size occur?
a. When natality and immigration are greater than mortality and
emigrations.
b. When mortality and emigration are greater than natality and
immigration.
c. When there is no emigration or immigration.
d. When natality and immigration are equal to mortality and emigration.
15. Which of the following will cause a population to increase?
a. A decrease in natality
b. An increase in mortality
c. Limiting factors
d. An increase in biotic potential
16. A graph representing a population that is limited by a definite carrying
capacity is shaped like which letter?
a. S
b. J
c. L
d. U
17. A population reached a certain size, levelled off, and became stable. Which of
the following is most appropriate description?
a. Natality and mortality were equal.
b. The biotic potential of the environment decreased.
c. The population reached the carrying capacity of the environment
d. Another species in the same niche competed with the population.
18. Which of the following is a density independent factor that limits population
growth
a. A tornado destroying a stand of pine trees
b. Two species competing for the same food source
c. A disease passing through a population of pigs on a farm
d. Snowy owls preying on arctic hares
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19. Which of the following is most true about interspecific competition?
a. It involves interaction between individuals of the same species.
b. It is the greatest between organisms that occupy different ecological
niches.
c. It is the greatest between organisms that physically share similar
ecological niches.
d. It increases with resource partitioning.
20. Which of the following is true in relation to predation?
a. The predator is negatively affected and the prey is positively affected.
b. The predator population always increases and the prey population
always decreases in size.
c. The predator-prey population cycle exhibits a sinusoidal pattern on a
graph.
d. The snowshoe hare and lynx cycling study demonstrated that predator
prey cycling is not influenced by any other factors.
21. What is the term for a plant or animal species introduced into a community
where it may disrupt the balance in an ecosystem and threaten biodiversity?
a. Parasite
b. Predator
c. Indigenous species
d. Exotic species
22. Birds find shelter and build nests in trees without harming the trees. What is
the symbiotic relationship between the birds and the trees?
a. Mutualism
b. Parasitism
c. Commensalism
d. Predation
23. A beetle called the locust borer has black and yellow stripes on its body and
buzzes like a bee when picked up. The defensive strategy used by the locust
borer maybe called:
a. Camouflage
b. Chemical defence
c. Mimicry
d. Protective coloration
24. Which of the following interactions is a win-win relationship?
a. Symbiosis
b. Parasitism
c. Commensalism
d. Mutualism
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25. Which of the following statements about succession is NOT true?
a. Pioneer plant species are larger than climax species
b. Secondary succession occurs after a fire or other devastation
c. Primary succession occurs in an area where no community existed
previously
d. The total number of species increases dramatically during the early
stages of succession.
26. As succession proceeds
a. The number of species decreases
b. Biomass increases for about 100 years and then decreases sharply
c. Net productivity increases and then levels off after about 40 years
d. The number of species increases and then levels off after about 40
years.
Short Answer: Read the articles carefully and answer the questions following in a
couple sentences.
Article 22.2 Carrying capacity
Carrying capacity refers to the maximum abundance of a species that can be sustained
within a given area of habitat. When an ideal population is at equilibrium with the
carrying capacity of its environment, the birth and death rates are equal, and size of the
population does not change. Populations larger than the carrying capacity are not
sustainable, and will degrade their habitat.
Carrying capacity for humans
Humans are clever at developing and using technologies; as a result they have an
unparalleled ability to manipulate the carrying capacity of the environment in support of
their own activities. When prehistoric humans first discovered that crude tools and
weapons allowed greater effectiveness in gathering wild foods and hunting animals, they
effectively increased the carrying capacity of the environment for their species. The
subsequent development and improvement of agricultural systems has had a similar
effect, as have discoveries in medicine and industrial technology.
Humans have also increased the carrying capacity of the environment for a few other
species, including those with which we live in a mutually beneficial symbiosis. Those
companion species include more than about 20 billion domestic animals such as cows,
horses, pigs, sheep, goats, dogs, cats, and chickens, as well as certain plants such as
wheat, rice, barley, maize, tomato, and cabbage. Clearly, humans and their selected
companions have benefited greatly through active management of Earth's carrying
capacity.
In addition, there are increasingly powerful indications that the intensity of environmental
exploitation required to sustain the large populations of humans and our symbionts is
causing important degradations of carrying capacity. Symptoms of this environmental
deterioration include the extinction crisis, decreased soil fertility, desertification,
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deforestation, fishery declines, pollution, and increased competition among nations for
scarce resources. Many reputable scientists believe that the sustainable limits of Earth's
carrying capacity for the human enterprise may already have been exceeded. This is a
worrisome circumstance, especially because it is predicted that there will be additional
large increases in the global population of humans. The degradation of Earth's carrying
capacity for humans is associated with two integrated factors: (1) overpopulation and (2)
the intensity of resource use and pollution. In recent decades human populations have
been growing most quickly in poorer countries, but the most intense lifestyles occur in
the richest countries.
Source Citation: Freedman, Bill. "Carrying capacity." Gale Encyclopedia of Science.
Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 3rd ed. Detroit: Gale, 2004. Science
Resource Center. Thomson Gale. 14 December 2006
Document Number: CV2644030418
Use Article 22.2 to answer questions 27, 29 & 29.
27. Some people argue that diseases like AIDS, West Nile Virus, and Bird flu are
‘nature’s way’ of controlling the population. Which population determining
factor is affecting growth if this hypothesis is correct? Explain how will this
slow the growth of the human population.
28. While raising the carrying capacity of our environment, we have raised the
carrying capacity for many other species, as well. Explain how agriculture has
had this effect.
29. What two factors have degraded the Earth’s carrying capacity?
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Scenario 21.1 Hardy-Weinberg Principle
“Known as the Hardy-Weinberg Principle, this mathematical relationship shows that
allele frequencies will not change from generation to generation, as long as certain
conditions are met.” (from, Nelson, Biology 30, p. 718)
Use Scenario 21.2 to answer questions 30, 31 & 32.
30. The allele for sickle-cell anemia is constant in Africa, as predicted by HardyWeinberg. Hypothesize as to why its frequency is decreasing in North
America
31. Explain how migration changes the predictions of the Hardy-Weinberg
Principle.
32. If humanity suddenly decided that blue eyes were a desirable trait, predict
what would happen to the frequency of the (recessive) allele for blue eyes.
Justify your prediction.
33. There has been an “alarming six-fold increase in the rate of antibiotic
resistance in Canada between 1995 and 1999.” You hear a parent complaining
to their child’s doctor that modern medicine has “created a monster” by
making new bacteria that are resistant to antibiotics. Criticize their statement,
correcting their misconception.
Article 23.1 Introduced species
Introduced species (also called invasive species) are those that have been released by
humans into an area to which they are not native. These releases can occur accidentally,
from places such as the cargo holds of ships. They can also occur intentionally, and
species have been introduced for a range of ornamental and recreational uses, as well as
for agricultural, medicinal, and pest control purposes. Introduced species can have
dramatically unpredictable effects on the environment and native species. Such effects
can include overabundance of the introduced species, competitive displacement, and
disease-caused mortality of the native species.
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Although introduced species are usually regarded with concern, they can occasionally be
used to some benefit. The water hyacinth is an aquatic plant of tropical origin that has
become a serious clogging nuisance in lakes, streams, and waterways in the southern
United States. Numerous methods of physical and chemical removal have been attempted
to eradicate or control it, but research has also established that the plant can improve
water quality. The water hyacinth has proved useful in the withdrawal of nutrients from
sewage and other wastewater. Many constructed wetlands, polishing ponds, and waste
lagoons in waste treatment plants now take advantage of this fact by routing wastewater
through floating beds of water hyacinth.
Due to the difficulties and expense required to protect native species and to eradicate
introduced species, there are not many international laws and policies that seek to prevent
these problems before they begin. Thus customs agents at ports and airports routinely
check luggage and cargo for live plant and animal materials to prevent the accidental or
deliberate transport of non-native species. Quarantine policies are also designed to reduce
the probability of spreading introduced species, particularly diseases, from one country
to another.
Source Citation: Vedagiri, Usha and Smith, Douglas. "Introduced species."
Environmental Encyclopedia. Ed. Marci Bortman and Peter Brimblecombe. 3rd ed.
Detroit: Gale, 2003. Science Resource Center. Thomson Gale. 14 December 2006
Document Number: CV2644150746
Use Article 23.1 to answer 34 & 35.
34. Many people consider introduced species as harmful to the environment.
Using the example of the water hyacinth, explain how invading species may
benefit their new environment.
35. Before the construction of the Confederation Bridge linking Prince Edward
Island to the mainland, the only access to P/E.I. was by ferry boat. Car wheels
and the underside of cars were washes well before being loaded onto a boat
for the Island. Cars from P.E.I. were not treated this way. Hypothesize the
reason for washing the undersides of cars before they were allowed on Prince
Edward Island.
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Article 23.2 Old-growth forest
Which is more important: a lumberman's job or the survival of the northern spotted owl?
That question highlights one of the most dramatic ecological debates going on in the
United States today. The debate centers on old-growth forests, which are ecosystems
dominated by large, old trees, usually representing many species. The physical structure
of old-growth forests is very complex, and includes multiple layers and gaps of foliage
within the canopy, great variations of tree sizes, and many large, standing dead trees and
dead logs lying on the forest floor.
Old-growth forests provide a habitat with very special ecological characteristics. These
features are not present or as well developed in forests that are younger than old-growth
forests. Some wildlife species require these specific qualities of old-growth habitats. As a
result, they need extensive areas of old-growth forest as all or a major part of their range.
Some well-known, North American examples of species considered to be dependent on
old-growth forests are birds such as the northern spotted owl, marbled murrelet, and redcockaded woodpecker, and mammals such as marten and fisher. Some species of plants
may also require or be much more abundant in old-growth forests than in younger,
mature forests. Examples include Pacific yew and various species of lichens occurring in
old-growth Douglas fir forests of western North America.
The controversy over jobs versus owls arises because old-growth forests contain many
very old, very large trees of highly desirable species. Lumber companies can realize very
large economic profits from the cutting and removal of old-growth trees.
The destruction of old-growth forests presents two problems. In the first place, the loss of
such forests destroys the habitats of many animals, such as the spotted owl and the
marbled murrelet. Additionally, such forests are unlikely to be replaced. They develop
over hundreds or thousands of years when left entirely untouched. In an age when
humans are eager to harvest as much mature wood as possible, the chances of new oldgrowth forests developing are relatively small.
Source Citation: "Old-growth forest." U*X*L Science. Online Edition Detroit: U*X*L,
2004. Science Resource Center. Thomson Gale. 14 December 2006
Document Number: CV2646000715
Use Article 23.2 to answer questions 36 & 37.
36. In terms of succession, how would old-growth forest be classified? Quote the
line in the article that lead to this conclusion.
37. The trees in an old-growth forest are very big and very old, in general. Why
are lumber companies interested in these trees?
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