Chapter 54

Which of the following events would move energy and material from a detritivore into a higher trophic level in a food web? a. A beetle eats the leaves of a living plant. b. An earthworm eats dead leaves on the forest floor. c. A robin catches and eats an earthworm. d. A falcon eats a robin. e. A bacterium decomposes the feces of an earthworm.

The total dry weight of plant material in a forest is a measure of the forest's: a. gross primary productivity. b. net primary productivity. c. cellular respiration. d. standing crop biomass. e. ecological efficiency.

Which of the following ecosystems has the highest rate of net primary productivity? a. open ocean b. temperate deciduous forest c. tropical rainforest d. desert and thornwoods e. cultivated land

Some freshwater and marine ecosystems exhibit an inverted pyramid of: a. biomass. b. energy. c. numbers. d. turnover. e. ecological efficiency.

Which process moves nutrients from the available organic compartment to the available inorganic compartment? a. respiration b. erosion c. assimilation d. sedimentation e. photosynthesis

Which of the following materials has a sedimentary cycle? a. water b. oxygen c. nitrogen d. phosphorus e. carbon

Nitrogen fixation converts: a. atmospheric molecular nitrogen to ammonia. b. nitrates to nitrites. c. ammonia to molecular nitrogen. d. ammonia to nitrates. e. nitrites to nitrates.

Endothermic animals exhibit a lower ecological efficiency than ectothermic animals because: a. endotherms are less successful hunters than ectotherms. b. endotherms eat more plant material than ectotherms. c. endotherms are larger than ectotherms. d. endotherms produce fewer offspring than ectotherms. e. endotherms use more energy to maintain body temperature than ectotherms.

The amount of energy available at the highest trophic level in an ecosystem is determined by: a. only the gross primary productivity of the ecosystem. b. only the net primary productivity of the ecosystem. c. the gross primary productivity and the standing crop biomass. d. the net primary productivity and the ecological efficiencies of herbivores. e. the net primary productivity and the ecological efficiencies at all lower trophic levels.

If you were growing a vegetable garden, identify the factors that might affect its primary productivity. How would you increase productivity? Identify some possible consequences of your gardening activities to nearby ecosystems.

A lake near your home became overgrown with algae and pond-weeds a few months after a new housing development was built nearby. What data would you collect to determine whether the housing development might be responsible for the changes in the lake?

Some politicians question whether the recent increase in atmospheric temperature results from our release of greenhouse gases into the atmosphere. They argue that atmospheric temperature has fluctuated widely over Earth's history, and the changing temperature is just part of a historical trend. What information would allow you to refute or confirm their hypothesis? In addition, describe the pros and cons of reducing greenhouse gases as soon as possible versus taking a a "wait and see" approach to this question.

If you could design the ideal farm animal-one that was grown as food for humans-from scratch, what characteristics would it have?

Design an experiment to test the hypothesis that predators in an aquatic ecosystem regulate the ecosystem's primary productivity. Establish as many experimental ponds as you wish, and imagine stocking them with organisms at different trophic levels. If the hypothesis is correct, describe the results you would expect to record from each of your experimental treatments.