CVJI 7

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Question 1 of 20
Joseph Connell’s “intermediate disturbance hypothesis” proposes that:
A. species diversity is highest at intermediate frequencies of disturbance.
B. species diversity is lowest at intermediate frequencies of disturbance.
C. population growth rates are highest at intermediate frequencies of disturbance.
D. competitive exclusion is fastest at intermediate levels of disturbance.
Question 2 of 20
A “community” is defined as:
A. a group of organisms that all make their living in a similar way.
B. a group of individuals of a single species inhabiting a defined area.
C. the portion of a defined area that supports life.
D. an association of interacting species inhabiting a defined area.
Question 3 of 20
In most ecological communities:
A. most species are extremely rare.
B. few species are very abundant.
C. most species are moderately abundant.
D. both few species are very abundant, and most species are moderately abundant.
Question 4 of 20
Robert MacArthur’s study of forest warblers suggested that:
A. fewer warbler species can survive in more complex habitats.
B. warbler species diversity increases with habitat complexity.
C. warbler species diversity decreases with habitat complexity.
D. most warblers have rather similar foraging niches.
Question 5 of 20
Niches of single-celled algae, such as diatoms, seem most often to be distinguished by their requirements for:
A. different combinations of inorganic nutrients.
B. different light environments.
C. different water-flow environments.
D. different water temperatures.
Question 6 of 20
In the Amazon forest, slight changes in soil properties tend to be correlated with:
A. similar, slight differences in plant communities.
B. no detectable differences in plant communities.
C. dramatic differences in plant communities.
D. dramatic differences in plant communities only if the soil property in question is moisture.
Question 7 of 20
In Robert Paine’s studies of the Washington intertidal community, which organism proved to be a keystone species?
A. The whelk Thais
B. Acorn barnacles
C. Chitons
D. The starfish Pisaster
Question 8 of 20
In the Washington intertidal community studied by Robert Paine, the most important limiting resource is:
A. space.
B. light.
C. plankton.
D. nitrogen.
Question 9 of 20
We can infer a statistically significant difference between two population means when:
A. our estimates of the two means are different.
B. the variances of the two means do not overlap.
C. the standard deviations of the two means do not overlap.
D. the 95% confidence intervals for the two means do not overlap.
Question 10 of 20
Weaver ants provide effective protection of citrus trees because they:
A. remove harmful soft-scale insects (mealybugs).
B. remove all plant-feeding insects.
C. cultivate soft-scale insects, but do not allow them to feed on the trees.
D. cultivate soft-scale insects, but still allow them to be attacked by parasitoids and predators.
Question 11 of 20
The Nile perch population explosion has been accompanied by:
A. a decrease in the dissolved oxygen in the shallowest portions of Lake Victoria.
B. a decrease in the dissolved oxygen in the deepest portions of Lake Victoria.
C. an increase in the dissolved oxygen in the deepest portions of Lake Victoria.
D. an increase in the dissolved oxygen in the shallowest portions of Lake Victoria.
Question 12 of 20
Based on studies by Jane Lubchenko, what influence does the population density of the herbivorous intertidal snail, Littorina littorea, have on the number of algal species?
A. As snail density increases from low to medium, the number of algal species increases.
B. As snail density increases from medium to high, the number of algal species increases.
C. As snail density increases from medium to high, the number of algal species decreases.
D. Both as snail density increases from low to medium the number of algal species increases and as snail density increases from medium to high, the number of algal species decreases.
Question 13 of 20
Teja Tscharntke simplified the food web associated with the wetland reed Phragmites australis by dividing the species into the following major trophic levels?
A. Plant, herbivore, piscivore, and granivore
B. Herbivore, carnivore, detritivore, and consumer
C. Herbivore, parasite, carnivore, and detritivore
D. Plant, herbivore, parasite, and carnivore
Question 14 of 20
Net primary productivity is the primary productivity of an ecosystem, after subtracting energy lost in:
A. dead plant tissues.
B. inedible plant tissues.
C. respiration by primary producers.
D. respiration by primary consumers.
Question 15 of 20
“Actual evapotranspiration” for an ecosystem refers to the amount of water that:
A. is taken up from soils by plant roots.
B. evaporates from soils.
C. is transpired by plants.
D. evaporates from soils plus the amount transpired by plants.
Question 16 of 20
Leibig’s “Law of the Minimum” stated that:
A. the lowest primary productivity occurs in the coldest ecosystems.
B. primary productivity is typically controlled entirely by climate.
C. primary productivity is typically controlled by both climate and soil nutrients.
D. a single soil nutrient typically limits primary productivity.
Question 17 of 20
Experimental fertilizations in the Baltic Sea suggest that primary productivity there is normally limited by:
A. phosphorus.
B. nitrogen.
C. iron.
D. potassium.
Question 18 of 20
The “trophic cascade hypothesis” emphasizes the role of:
A. nutrients in controlling primary productivity.
B. nutrients in controlling primary consumption.
C. grazing by herbivores in controlling primary productivity.
D. grazing by herbivores in controlling ecosystem nutrient levels.
Question 19 of 20
In Hubbard Brook Experimental Forest, the largest “standing stock” of energy is represented by biomass of:
A. living plant tissues.
B. dead plant tissues.
C. invertebrate herbivores.
D. vertebrate herbivores.
Question 20 of 20
An increase about 1,000 years ago in 13C content of human collagen from archeological sites in eastern North America probably records:
A. replacement of vegetables and grains in the diet by meat.
B. replacement of corn by beans and squash in the diet.
C. increasing consumption of corn.
D. increasing levels of 13C in soils.