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BIOLOGY 262, FALL 2003
IN-CLASS EXAMINATION #1 (PART 1)
Date
Key
MULTIPLE CHOICE.For the following multiple choice questions circle the letter in front of the
response that best answers the question or completes the sentence. (20%, 2% each)
1. Which of the following is an assumption
of scientific philosophy?
a. Different events cannot have the
same cause.
b. Only experimental observations can
prove hypotheses to be true.
c. Sense experience reflects reality.
d. The universe is disordered.
e. None of the above. (None are assumptions
of scientific philosophy)
2. In an experimental study, the group that
does not receive the treatment is the…
a. experimental group.
b. naturalistic group.
c. negative control group.
d. positive control group.
e. None of the above.
6. Currently, what is the most-significant
cause of species becoming endangered?
a. Commercial overexploitation
b. Effects of exotic organism
c. Habitat alteration (destruction)
d. Recreational disturbance &
overexploitation
e. None of the above
7. Which of the following best describes the
interaction between bean plants (legumes)
and nitrogen-fixing bacteria (Rhizobium)?
a. Amensalism.
b. Commensalism.
c. Competition.
d. Parasitism.
e. None of the above.
3. Which of the following would be the most
effective way to decrease the size of a
cockroach population in a house?
a. decrease d
b. decrease K
c. increase d
d. increase K
e. increase r
8. If a population of 1,000 is undergoing
exponential growth with a yearly intrinsic
rate of increase of 0.50, then what is the
size of the population after 2 years?
a. 500
b. 750
c. 1500
d. 2000
e. None of the above - 2250
4. Which of the following should have the
greatest species richness?
a. Baja California Peninsula.
b. Catalina Island (close to California)
c. Nunivak Island (close to Alaska)
d. San Clemente Island (far off
California)
e. Southern California.
9. Which of the following describes the
distribution of Cthalamus barnacles only
in the higher, dryer intertidal areas?
a. Exploitative competition.
b. Fundamental niche.
c. Interference competition.
d. Realized niche.
e. None of the above.
5. Which of the following habitat patches
should theoretically have the most interior
species? (assume all have equal area)
a.
b.
10. Which of the following is generally the
most photosynthetically productive (and
thus fisheries productive) area of the
ocean?
a. Above the continental shelf.
b. Bottom of the open ocean.
c. In deep ocean trenches.
d. Open ocean near the surface.
e. Open ocean far below the surface.
c.
d.
FILL-IN-THE-BLANK.For the following write the appropriate number(s), word(s), sketch(es),
or line(s) in the indicated spaces.(10%)
1. Fill in the empty cells in the life table
below for a cohort of sea turtles. (4.5%)
Age Number Survivorship. Mortality
Rate
3. Hypothesis: The presence of species A
reduces the population size of species B.
Data Based on Quadrat Samples
mean # of species B (no sp. A) = 543.5
mean # of species B (with sp. A) = 354.9
P-value = 0.06
0
5000
1.000
0.90
1
500
0.100
0.80
2
100
0.020
0.50
3
50
0.010
0.20
Explain why the hypothesis was supported
or rejected. (2%)
4
40
0.008
----
Means support the hypothesis.
2. Use the data above to complete the
survivorship line graph below. (1%)
survivor0.50
ship
0.00
0
Hypothesis supported or rejected? (1%)
REJECTED
However, the P-value shows the
differences were not significant.
4. Identify three (3) community interactions
that could explain why the presence of
one species reduces the population size
of another species. (1.5%)
Any Community interaction where
one species experiences a negative.
1
2
Age
3
Amensalism, Batesian mimicry,
Competition, Parasitism,
Parasitoidism, Predation
DEFINITIONS.For the following BIOLOGICAL words or phrases define them as accurately
and concisely as possible. (For indicated questions provide an example as well.) (20%, 4% each)
1. Science:
A belief that natural phenomena have natural causes that can be revealed by empirical
evidence.
2. Population:
Individuals of the same species in a single area.
3. Maritime Climate:
A more moderate climate when winds blow from ocean to land. (As contrasted with the
very variable continental climate.)
4. Ecological Succession (define AND provide an example):
Change in community structure over time (usually regulated by competition). SOME
EXAMPLES: oak forest to maple forest, pine forest to oak/hickory, tooth plaque and bacterial
change, sequence of colonization of newly formed oceanic islands, etc.
5. Müllerian mimicry (define AND provide an example):
Being poisonous or venomous and advertising in the same way as other poisonous or
venomous species. (a positive - positive interaction) EXAMPLES: bees & wasps, Heliconius
butterflies, etc.
Name
Key
BIOLOGY 262, FALL 2003
IN-CLASS EXAMINATION #1 (PART 2)
Date
FREE RESPONSE QUESTIONS/PROBLEMS. Address each question in as concise and lucid a
manner as possible. (50%)
1. A population of 100 guppies (small fish) in a pond is growing logistically and has a yearly
intrinsic rate of increase of 0.95. The carrying capacity is 10,000. What is the size of this
population after one year? After two years? Show your calculations. At what population size
will this population be adding the greatest number of individuals per unit time? (10%)
* ∆N/∆t = 0.95 (100) [(10000-100)/10000] = 94.05 (rounding is OK)
size after 1 year = 100 + 94.05 = 194.05
(4%)
* ∆N/∆t = 0.95 (194.05) [(10000-194.05)/10000] = 180.77 (rounding is OK)
size after 2 years = 194.05 + 180.77 = 374.082
(4%)
* The population would grow most rapidly at ½ K ( ½ carrying capacity) which
would be at 5,000. (2%, students could either explain or provide the number 5000)
2. Briefly provide explanations for why it is warm at the equator and cool at the poles, also
explain why it is wet at the equator and dry at 30° N and S latitude. (Feel free but do not feel
obliged to use a sketch as part of your answer.) (10%)
* It is warm at the equator because the sunlight strikes the earth more directly
there. It is cooler at the poles because the sunlight strikes the earth more indirectly
(obliquely) there. (5%)
* This wet dry pattern is due to air circulation cells (also called the intertropcal
convergence). The equator is warmer thus the warmer and wetter air at the
equator rises. As it rises it cools releasing its moisture as rain. The air moves at
high altitude to 30°N and S latitude where it descends and warms. As it warms its
moisture capacity increases and it absorbs moisture from the land. (The air then
moves at low altitude back towards the equator.) (5%)
3. You are given the task of managing a population of quail and other species of game birds in an area
near a fully protected national park. The populations of game birds outside the park were depleted
through habitat destruction and over hunting. You can protect only a limited area of habitat as a
protected preserve and you cannot completely prohibit hunting (although you can impose some
hunting limitations). a.) Where would you place your preserve with respect to the National
Park and how would you shape your preserve? Why? b.) Which individuals in the
populations of these bird species would you protect from hunting to ensure a growing
population? Why? (10%)
a.) It would be best to shape the preserve compactly and place it close to or adjacent to
the National Park. (It would also be good is students shaped the preserve in a noncompact , elongate way if it is “pressed up against” the National Park. ) Compactness
would reduce “edge” habitat and increase interior habitat. Proximity to the park
would increase the recolonization rate (island biogeography) or would allow the
national park to serve as a source population if the preserve starts to act as a sink
population. (5%)
b.) It would be best to protect individuals of higher reproductive value such as females or
individuals of an age right before first reproduction. This would ensure that the
population would continue to grow since the individuals removed by hunting are not
those with the greatest ability to contribute to population growth. (5%)
4. The following is a summary of the results of a study of coyotes (Canis latrans) in western Texas.
Rodents and jackrabbits consume plants. Both coyotes and mustelids are rodent predators. Coyotes
also consume some plant material, jackrabbits, and very rarely mustelids. Coyotes are frequently shot
by ranchers who fear coyotes will prey on young sheep or cattle.
Four 5000 hectare sites were studied. In two sites coyotes were removed. Despite removal of large
numbers of coyotes, removal was only partially effective and large numbers of immigrant coyotes
kept the coyote population at about 50% of the size it was in the test areas where the coyotes were not
removed. (A real study conducted in 1990-1992.) (20%)
# Rodent Species
Total # of Individual
# Mustelid Species
Total # of Individual
Total # of Individual
Rodents sampled
(weasels, skunks, etc.)
Mustelids Sampled
Jackrabbits Sampled
6768
5
233
235
5649
5
254
342
Coyotes remain
1 -Ord's kangaroo rat
9087
5
556
1540
Coyotes removed
1 -Ord's kangaroo rat
7839
5
690
3280
Coyotes removed
a. Identify the trophic “levels” (or trophic classification) of (i) the plants, (ii) the rodents, (iii) the
jackrabbits, (iv) the mustelids, and (v) the coyotes.
b. Briefly, in a sentence, explain the relationships among coyote subpopulations (i.e., the
relationship of the surrounding areas to the areas from which coyotes were removed.
c. If you were managing an area in west Texas as a wildlife preserve (with a goal of maintaining
as much biodiversity as possible), would it be better to remove or retain coyotes? Why?
(Or… to put “Why?” another way… Explain the effect that coyotes have on the species
richness of west Texas?)
d. Provide two (2) possible explanations for why the areas with fewer coyotes have more total
rodents and jackrabbits but have fewer species of rodents? In both possible explanations
mention at least one community interaction that could cause this result?
Coyotes remain
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a.) i. plants) primary producers or photosynthesizers (1%); ii. rodents) primary
consumers or herbivores (1%); iii. jackrabbits) primary consumers or herbivores (1%);
iv. mustelids) secondary consumers or carnivores (1%); iv. coyotes) omnivores (1%)
b.) The areas where coyotes were continuously removed .were sink populations (requiring
immigrants) and the surrounding areas were source populations (producing
immigrants). (3%)
c.) It would be better to retain them because they are functioning as a keystone species
(students could also explain what a keystone species does rather than simply using the
phrase). (4%)
d.) (8%; 4% for each of 2 possible explanations)
ONE EXPLANATION – Ord’s kangaroo rat and jackrabbits competitively exclude the
other rodent species except when its numbers are reduced by predation by coyotes.
ANOTHER EXPLANATION – Mustelids preferentially predate upon other rodents in
preference to Ord’s kangaroo rat or jackrabbits. Reduction of coyote predation on
mustelids allowed mustelids to increase in numbers and thus prey upon the other
rodent species until they were no longer found in the area.
ANOTHER EXPLANATION (very unlikely but acceptable)– Jackrabbits have an amensal
relationship with most species of rodents (except for Ord’s kangaroo rat). Removal of
coyotes allowed an increase in jackrabbit populations which caused a decrease in
the number of species of rodents.
ANOTHER EXPLANATION (very unlikely but acceptable)– Coyotes consume plant
material that is preferred by Ord’s kangaroo rat and jackrabbits. Removal of coyotes
made more of this available to the kangaroo rats and jackrabbits which then
increased in population size and were able to competitively exclude the other rodent
species.
Any other possible scenarios.