Download Example Midterm 04

NAME______________________________
MIDTERM EXAMINATION
MS 103 MARINE ECOLOGY
1(20)______________6(30)____________
FALL 2004
2(5)_______________7(30)____________
GRAHAM, GELLER, HUGHES
3(10)______________8(25)____________
4(10)______________9(20)____________
5(10)______________10(20)___________
TOTAL (180)____________
Note: You will have three hours for this examination, which contains 10 questions. Each
question will be independently graded (the value of each question is in parentheses, and is also an
estimate of the maximum number of minutes it should take to answer). Attempt to answer each
question in the space provided (if you need more, use the opposite side).
1 (20). Define the terms below using 2 sentences (1 point for definition; 1 point for contextual
example)
a. Pseudoreplication
b. Paradigm
c. Mensurative experiment
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d. Meta-population
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Question 1 (definitions) continued:
e. Allee effect
f. Upwelling relaxation
g
h. FST
i. Effective population size
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j. Cryptic species
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2 (5). What is the difference between interference competition and exploitative competition?
3 (10). Why is recruitment limitation less likely for barnacle populations in Oregon compared to
those in California? Would you expect this geographic difference in recruitment
limitation to increase or decrease during El Nino conditions? Why (be brief)?
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4 (10). Discuss the pro’s and con’s of using (a) systematic and (b) random designs for
interspersing experimental treatments, and how these two designs may give different results
depending on whether the underlying environmental spatial pattern is patchy or uniform. What
other type of treatment interspersion design would be useful when the underlying environmental
spatial pattern is in the form of a gradient?
5 (10). Briefly explain the rocky intertidal zonation paradigm: what determines the upper vs.
lower limits of species boundaries?
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6 (30). The Monterey Bay National Marine Sanctuary Research Activity Panel (RAP) is
concerned that kelp canopy harvesting inside Monterey Bay may significantly impact blue
rockfish populations. Blue rockfish larvae are planktotrophic and spend many weeks in the
plankton before settling preferentially into canopies of the giant kelp Macrocystis pyrifera. As
they grow older, the juveniles lose their strict association with the canopies, although schools of
juvenile and adult blue rockfish continue to aggregate in coastal kelp forests in Monterey Bay.
Furthermore, based on surface current patterns, it has been proposed that blue rockfish from
Monterey Bay form a closed population relative to blue rockfish along the open coast of the
Sanctuary.
a) Define open vs. closed populations and discuss how differentiation between the two is relevant
to the theory of metapopulation dynamics
b) Briefly describe field demographic studies that would need to be conducted to determine if
blue rockfish from Monterey Bay do in fact form a closed population
c) Briefly describe how genetic methods could be used to determine if the population is closed
d) If the Monterey Bay blue rockfish population is closed, would it be more or less vulnerable to
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kelp harvesting? Why?
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7 (30). While exploring the high intertidal at Hopkins Marine Station, you make the following
observation: although there is a high % cover of bare rock, periwinkle snails (Littorina) appear to
aggregate around the base of clumps of red algae (Endocladia).
a) Using this observation, design a study to demonstrate your knowledge of the processes of the
scientific method that occur after OBSERVATION and prior to INTERPRETATION (as
discussed in Underwood 1997).
b) Assuming your observation was accurate and that the experiment you described was
completed, discuss the first step you would take after both (1) retaining your null hypothesis, or
(2) rejecting your null hypothesis.
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c) What is the benefit of developing many alternative models?
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8 (25). You have just initiated a study to determine the interaction strength between an intertidal
predator (the dogwhelk Nucella) and its sessile prey (the barnacle Balanus). Your created many
replicates of your treatments at four locations: high and low tidal heights (within the tidal range
of both species), at both wave exposed and protected sites.
a) Briefly describe what type of manipulation you would have done, and how
interaction strength can be estimated from the data
b) Based on the various general models discussed in class, predict the ranking of interaction
strength to be observed among the four locations (i.e. high exposed vs. low exposed vs. high
protected vs. low protected), and discuss why this ranking is likely.
c) What factors other than predation might confound your results, and how might you control for
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these confounding factors?
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9 (20). Molecular data can be used to analyze gene frequencies in populations, as well as the
genealogical relationships of genes. These two approaches to genetic analysis allow us to make
inferences about population connectivity, local adaptation, and demographic history.
a) From direct observation of the movements of larvae, we know that two hypothetical
populations are rarely exchanging propagules. Yet, molecular data tell us that the two
populations are very similar genetically. What are “equilibrium” and “non-equilibrium”
explanations for this result?
b) Dispersal results in gene flow, and this limits the extent of local adaptation that is possible for
a population. Barnacles, for instance, have great dispersal ability and have large geographic
ranges. Yet, we do see morphological variation within the range of one species in Baja
California, Chthamalus anisopoma. In some places, barnacles grow in peculiar hooded shape,
whereas in others they grow in a typical conical form. How can this morphological variation
occur given high gene flow in this species?
c) How can patterns of coalescence be used to infer an historical range expansion?
d) Coalescent theory predicts different shapes for phylogenetic trees from persistently large
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populations and those that experience frequent population crashes. How should these trees differ
(make a sketch if you like), and why
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10 (20). Modern biotas are shaped by invasion, in situ evolution, and extinction. Discuss how
these factors have interplayed in the evolution of the northern hemisphere temperate marine
biota, using examples drawn from lecture, textbook, and supplemental readings.