NAME______________________________
FINAL EXAMINATION
MS 103 MARINE ECOLOGY
1(20)______________6(20)____________
FALL 2004
2(15)______________7(25)____________
GRAHAM, GELLER, HUGHES
3(10)______________8(10)____________
4(30)______________9(15)____________
5(20)______________
TOTAL (165)____________
Note: You will have three hours for this examination, which contains 9 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. Community
b. Foundation Species
c. Trophic cascade
d. Net primary productivity
NAME______________________________
e. Hermatypic
f. Adaptive bleaching
g. Redox potential discontinuity zone.
h. Facilitation
i.. Maximum sustainable yield
j. Ballast water
NAME______________________________
2 (15). It is predicted that over the next 100 years: (a) global sea levels will rise, (b) El Nino / La
Nina events will increase in frequency and intensity, and (c) exploitation of marine resources will
double. How might each of these processes affect terrestrial food webs on a series of circular
islands in the Gulf of California?
NAME______________________________
3 (10). Using a diagram, describe the life-cycle of giant kelp. Label all parts as appropriate.
Which life-history stage is the only one that is capable of dispersal?
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4 (30). Recall the paradigmatic role of sea otters and sea stars in structuring rocky subtidal and
intertidal communities, respectively, and how the strength of this role varies latitudinally.
Compare and contrast how local extinction of (i) sea otters and (ii) sea stars would have different
effects on their associated communities between (iii) the Pacific Northwest
(Aleutians/Washington) and (iv) southern California (i.e. describe 4 scenarios). In explaining the
rationale behind your answer, discuss the key information (specific studies or data) that
demonstrates this latitudinal gradient in predatory effects.
Subsequently, what do you think the utility of the keystone species concept is?
NAME______________________________
5 (20).
A (5/20) Briefly describe the structure of a coral reef, with focus on patterns of zonation and the
types of organisms in each zone.
B (15/20). Would you argue for a primary role for positive or negative interactions in structuring
coral reef communities? Or would you argue that neither have primacy? Take and defend
position..
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6 (20).
Rocky shores and salt marshes are both characterized by striking zonation patterns, which
prompts ecologists to ask whether vertical distributional patterns are controlled by similar
processes.
A (5/20). Describe zonation in a typical New England salt marsh and compare the controls on
vertical limits to those on a rocky shore.
B (15/20). The relative importance of positive interactions in any community has been
hypothesized to be related to levels of physical stress. Describe this relationship, and give
examples from salt marsh communities to illustrate such patterns.
NAME______________________________
7 (25).
The concept of amensalism is critical to our understanding of the structure of marine soft
sediment communities.
A (5/25). What is amensalism? How does amensalism differ from competition?
B (10/25). Describe amensalism in the context of mobility, and trophic functional groups.
C (10/25). Experimental removal of predators in soft sediment communities often leads to
increases in diversity, just the opposite of such experiments on rocky shores. Explain why this
might be, and what evidence exists to support your argument.
NAME______________________________
8 (10). Both the Georges Bank and Caribbean coral reefs have been subjected to intense human
exploitation, characterized as “fishing down the food web.” In both cases, sea urchins become
targets for exploitation as fishes were depleted. Compare the consequences of urchin removal in
these systems with respect to the initial “pristine” state for each.
NAME______________________________
9 (15). One of the greatest challenges in community ecology is the development of predictive
models for species invasions. Highlighting the difficulty of prediction, it is known that some
successful invading species had been frequently released in marine systems (usually
unintentionally) long before they became established.
A (6/15). Mechanistically, why might a repeatedly released species change from unsuccessful to
successful? Propose several hypotheses.
C (9/15), Choose one of your hypotheses and design an experiment to test one such hypothesis.