Chapter 7: Test Review Questions

Chapter 7: Test Review Questions Page 312

Complete questions 1-8, 10, 11, 13, 15, 16b, 17, 18, 22, 26

Answers to Review:

1. An ecosystem includes all the interacting parts of a biological community and its environment.

2. To endure means to continue in the same state. Sustainable ecosystems endure, but they also support a wide variety of organisms. All organisms require sustainable ecosystems for survival.

3. Students may choose to use the ruby-throated hummingbird or other migratory birds, American eels, the beluga whales in the St. Lawrence River, or peregrine falcons to show how ecosystems are connected. In the case of migratory birds many terrestrial ecosystems are connected, such as those in Canada, where the birds spend the summer breeding, and those in Central or South America, where the birds spend the winter, to every location in between where they may stop to rest and eat while migrating. The beluga whales and peregrine falcons are examples of how terrestrial and aquatic ecosystems are connected. Chemicals contained in run-off can biomagnify in the tissues of aquatic organisms, leading to heavy concentrations in the tissues of consumers higher in the food chain.

4. Competing for resources takes energy. Energy expended on competition is energy that is taken away from other important life processes, such as growth and reproduction.

5. The chemicals, such as those from industry, could bioaccumulate and undergo biomagnification, resulting in high concentrations in the tissues of consumers higher in the food chain. This could weaken the immune system of the organisms, leading to illness or death. It could also affect reproductive rates. Chemicals from agriculture could lead to eutrophication and an algae bloom. This could kick off a series of events that ultimately leads to the death of aquatic organisms, such as fish. In either case, all of the organisms connected to the organisms directly affected can also be affected due to changes in the food web as well as to the abiotic conditions of the ecosystem.

6. These locations have similar abiotic and biotic characteristics that support temperate deciduous forests.

7. Populations stay within their carrying capacities due to limiting factors, such as light, space, food availability, competition, predation, and symbiosis. 8. Density-independent factors are usually abiotic and include natural phenomena, such as weather events—extreme storms, droughts, floods, fires, cold snaps, and heat waves. Density-independent factors are usually biotic factors such as disease, parasites, predation, and competition.

10. No two species can occupy the exact same ecological niche or provide the exact same services to their ecosystem, because no two species live in exactly the same way.

11. Sustainable use of a resource is use that does not cause long-term depletion of the resource, or affect the diversity of the ecosystem from which the resource is obtained. An example of sustainable use would be to reduce our use of fossil fuels as much as possible in every aspect of our lives, including reusing, recycling, and reducing our consumption of products that require fossil fuels to make.

13. An ecological footprint is a measure of the impact of a human individual or population on the environment.

15. One possible cause is the Industrial Revolution.

16. (b) To meet the terms of the Protocol, countries can reduce emissions or get credits for removing carbon dioxide from the atmosphere by planting trees in nonforested areas.

17. Trophic efficiencies are usually quite low—they average only about 10 percent and often much less. This is because organisms use much of the energy from the biomass they consume for their life functions, and they produce wastes as well. Energy is also lost as heat from the bodies of organisms.

18. PCBs (polychlorinated biphenyls) were previously used by industries. PCBs entered water, air, and soil while they were being used and disposed of. The concentration of PCBs is biomagnified in higher-level consumers in a freshwater ecosystem such as a lake. Peregrine falcons were affected by both DDT and PCBs. After PCBs were banned, peregrine falcons were brought back from the brink of extinction by having captive birds produce young.

22. The carrying capacity is approximately 1.6 million. In real life, populations can exceed the carrying capacity, but then they will run out of food. Once they number less than the carrying capacity, their predators will run out of food and begin to die, allowing the population to grow to exceed the carrying capacity again.

26. Canadians use more electricity; consume more oil; and have more highways, which probably indicates more vehicle use. Canada is a colder country and requires more energy to keep warm.