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Problem 1
Fill in the blanks in the table below summarizing the interspecific interactions in a community.
- Fill in the blanks in the table below summarizing terrestrial nutrient cycles.
Problem 2
Problem 3
Which of the following groups is (are) absolutely essential to the functioning of an ecosystem?
a. Producers
b. Producers and herbivores
c. Producers, herbivores, and carnivores
d. Producers and decomposers
Problem 4
To ensure adequate nitrogen for a crop, a farmer would want to decrease _________ by soil bacteria.
a. Nitrification
b. Denitrification
c. Nitrogen fixation
d. a and c
- Which of the following organisms is mismatched with its trophic level? a. algae—producer b. phytoplankton—primary consumer c. carnivorous fish larvae—secondary consumer d. eagle—tertiary or quaternary consumer
Problem 5
Problem 6
Which of the following best illustrates ecological succession?
a. A mouse eats seeds, and an owl eats the mouse.
b. Decomposition in soil releases nitrogen that plants can use.
c. Grasses grow in a deserted field, followed by shrubs and then trees.
d. Imported pheasants increase in numbers, while local quail disappear.
Problem 7
The open ocean and tropical rain forests contribute the most to Earth's net primary production because
a. Both have high rates of net primary production
b. Both cover huge surface areas of Earth
c. Nutrients cycle fastest in these two ecosystems
d. The ocean covers a huge surface area, and the tropical rain-forest has a high rate of production
- Explain how seed dispersal by animals is an example of mutualism in some cases.
Problem 8
Problem 9
What is rapid eutrophication? What steps might be taken to slow this process?
- In Southeast Asia, there's an old saying: 'There is only one tiger to a hill.' In terms of energy flow in ecosystems, explain why big predatory animals such as tigers and sharks are relatively rare.
Problem 10
Problem 11
For which chemicals are biogeochemical cycles global? Explain.
- What roles do bacteria play in the nitrogen cycle?
Problem 12
Problem 13
An ecologist studying plants in the desert performed the following experiment. She staked out two identical plots, which included a few sagebrush plants and numerous small, annual wildflowers. She found the same five wildflower species in roughly equal numbers on both plots. She then enclosed one of the plots with a fence to keep out kangaroo rats, the most common grain-eaters of the area. After two years, to her surprise, four of the wildflower species were no longer present in the fenced plot, but one species had increased dramatically. The control plot had not changed. Using the principles of ecology, propose a hypothesis to explain her results. What additional evidence would support your hypothesis?
Problem 14
"In a classic study, John Teal measured energy flow in a salt marsh ecosystem. The table below shows some of his results.
a. What percentage of the energy in sunlight was converted into chemical energy and incorporated into plant biomass? What term describes this new biomass?
b. What percentage of the energy in plant biomass was incorporated into the bodies of the primary consumers? What became of the rest of the energy (see Figure 37.16A)?
c. How much energy is available for secondary consumers?
Based on the efficiency of energy transfer by primary consumers, estimate how much energy will be available to tertiary consumers."
