Review Questions Chp 45 (population Ecology) Key

Review Questions - Chapter 45 “Population Ecology”

1. Be able to define: ecology, demographics, population, habitat, population size, population density, population distribution, age structure, and reproductive base.

See text 2. In a population, the pre-reproductive ages and the reproductive ages together are counted as the __reproductive base________ __________. 3. List and describe the three  patterns of  dispersion illustrated by populations  in a  habitat.  Members of a population living in clumps is very common for these reasons: a. Suitable physical, chemical, and biological conditions are patchy, not uniform. b. Many animals form social groups. c. Many offspring are not highly mobile and are forced to live “where they landed.” 2. Uniform dispersion is rare in nature; when it does occur, it is usually the result of fierce competition for limited resources. 3. Random dispersion occurs in nature if environmental conditions are rather uniform in the habitat and members are neither attracting nor repelling each other.

3. 4. Describe the "capture-recapture method" used by ecologists.

See PPP for details

5. Distinguish immigration from emigration; define migration.

See PPP

6. Define zero population growth and describe how achieving it would affect population size.

Zero population growth designates a near balance of births and deaths.

7. In the equation G = rN, as long as r holds constant, any population will show __

exponential ________ growth.

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8. Calculate a population growth rate (G); use values for birth, death, and number of individuals (N) that seem appropriate. See PPP 9. State how increasing the death rate of a population affects its doubling time.

It will decrease it. 10. ___ biotic potential __ _____ __________ is the maximum rate of increase per individual under ideal conditions. 11. The _actual _________ rate of increase in population growth depends on the age at which each individual reproduces, and how many offspring are produced.

12. List several examples of limiting factors and explain how they influence population curves. Limiting factors (nutrient supply, predation, competition for space, pollution, and metabolic wastes) are collectively known as the environmental resistance to population growth. These all limit population growth.

13. Explain the phrase "overshot the carrying capacity," as applied to a population of

organisms in an environment. See PPP 14. Understand the meaning of the logistic growth equation and know how to calculate values of G by using the logistic growth equation. Understand the meaning of rmax and K. Refer to PPP 15. Contrast the conditions that promote J-shaped growth curves with those that promote S-shaped curves in populations.

J shaped curves occur during periods of growth where limiting factors are less effective. S shaped curves occur in the presence of significant limiting factors.

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16. Define density-dependent control of populations; cite one example.

The main density-dependent controls are competition for resources, predation, parasitism, and disease. These factors exert their effects in proportion to the number of individuals present. 17. Define density-independent factors and list two examples; indicate how such factors affect populations.

Some events, such as weather, tend to increase the death rate without respect to the number of individuals present. Lightning, floods, snowstorms, and the like affect large populations as well as small groups.

18. Most species have a ___life history_______ __________ pattern in that its individuals exhibit particular morphological, physiological, and behavioral traits that are adaptive to different conditions at different times in the life cycle. [p.692] 19. Life insurance companies and ecologists track a __cohort________, a group of individuals from the time of birth until the last one dies. [p.692] 20. Understand the significance and use of life tables; be able to list and interpret the three survivorship curves. Refer to PPP 21. Explain how the construction of life tables and survivorship curves can be useful to humans in managing the distribution of scarce resources. Planning!

Estimate the # of schools, hospitals etc that a community will need in the future. Plan taxes and spending accordingly. 22. Guppy populations targeted by killifish tend to be larger, less streamlined, and more brightly colored and guppy populations targeted by pike-cichlids tend to be smaller, more streamlined, and duller in color patterning. Other life history pattern differences exist between the two groups. After consideration of the research results obtained by Reznick and Endler, provide an explanation for these differences. [p.693]

OMIT

Be able to list three possible reasons that growth of the human population is out of control 

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1.    Humans expanded into new habitats and climatic zones. 2. Agriculture increased the carrying capacity of the land to support humans and their animals. 3. Medical practice and improved sanitation conditions removed many population-limiting factors.

23. Most governments are trying to lower birth rates by ___family planning _______ __________ programs. 24. Define total fertility rate. The number of births per female per

life time.

25. What is the significance of the cohort of 78 million baby boomers? 26. More than a third of the world population is now in the broad __reproductive ________ base. [p.696] 27. List and describe the four stages of the demographic transition model.

Demographic Transition Model . In the demographic transition model, changes in population growth are linked to four stages of economic development: a. In the preindustrial stage, living conditions are harsh, birth and death rates are high; there is little increase in population size. b. In the transitional stage, living conditions improve, death rate drops, birth rate remains high. c. In the industrial stage, growth slows. d. In the post-industrial stage, zero population growth is reached; birth rate falls below death rate. 28. Differences in population growth among countries correlate with levels of __economic development________ development. [p.698] 29. Be able to generally compare the implications of the resource consumptions of India and the United States. Refer to text and PPP 30. In the final analysis, no amount of _human_________ intervention can repeal the ultimate laws governing population growth, as imposed by the __limitations

(limiting factors)________ __________ of the environment.

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