Use this exam to review, and as a guide to what to expect for this year's midterm. Note that course content -- and information -- change from year to year, so if you see unfamiliar material or statistics here, go with what you've been told in class. You can click on Answers to jump to the answer key to this exam. You can also click on highlighted terms or phrases to jump to a place in the lecture notes where that topic was addressed.

1. A tree whose roots were weakened by road construction activities is uprooted in a storm and falls over, smashing a parked car. News reporters write, "A storm caused a tree to fall last night, smashing a parked car." What level of causation for the tree's falling are the reporters focusing on?
A. temporary
B. logistic
C. ultimate
D. proximate
E. sensationalist

2. Decomposition, nutrient cycling, and much of pest control in agricultural systems are examples of
A. negative feedback systems.
B. positive feedback systems.
C. ecosystem services.
D. resources that are priced according to their true value.
E. non-homeostatic regulation.

3. The article, "Human domination of Earth's ecosystems" by P.M. Vitousek and others suggests that (I can't give a web link -- take a look at the article again -- Course Documents on BlackBoard...)
A. human activities have ruined over 75% of the ice free land mass on Earth.
B. human activities use more than half of all Earth's accessible surface fresh water.
C. humans have diminished the availability of fixed nitrogen by about 50%.
D. humans have more than doubled the atmospheric concentration of CO2 in the last century.
E. humans have not yet had significant impacts on Earth's ecosystems, but are likely to within 50 years.

4. A "Cornucopian" tends to take a(an) ______ view of the consequences of continued growth of the human population, whereas a "Neo-Malthusian" takes a(an) ______ view of such consequences.
A. optimistic, pessimistic
B. pessimistic, optimistic
C. pessimistic, neutral
D. neutral, optimistic

5. Which of the parameters in the equation for calculating population growth over a time interval (G = rN), when multiplied by 100, gives the percentage rate of growth of a population?
A. G
B. r
C. N
D. None of these parameters will provide that information

6. If per capita birth rates (b) in a population decline, then r for that population must decline as well.
A. True
B. False

Use data from the following table to answer questions 7 - 9

Nation	Pop (millions)	Rate of natural increase (%)	Total Fertility Rate	% < 15 / % > 65
A	300	0.1	1.5	12 / 13
B	39	3.5	5.4	45 / 7
C	78	0.3	2.0	30 / 12
D	302	0.6	2.1	20 / 12
E	10	1.8	3.2	35 / 15

7. Which nation has reached zero population growth ("ZPG"), as defined by the UN?

8. Which nation most closely resembles the U.S. in mid-2007?

9. How many people will nation E add to its population (net addition; ignoring effects of migration) in the year for which data are provided?
A. 32,000,000
B. 320,000
C. 18,000,000
D. 180,000
E. Information given is insufficient to answer this question.

10. Which demographic parameter tells most directly the average number of children born per woman over her lifetime? (That is, which would tell you that number without your doing any calculations?)
A. Replacement level fertility
B. Crude birth rate
C. Total fertility rate
D. Rate of natural increase

The following two questions refer to
the figure on the right:

11. The population growth curve illustrated in the figure above reflects
A. logistic growth.
B. exponential growth.
C. deterministic growth.
D. multiplicative growth.
E. existential growth.

12. What is the carrying capacity of the environment for this population?
A. 100 people
B. 1,000 people
C. 10,000 people
D. 1,000,000 people
E. The graph provides no insights into the carrying capacity.

13. India has a very "triangular" age structure (many young people relative to a small number of older people). If total fertility rates in India decreased to replacement level right now, and remained at that level, what would happen to India's population size (ignoring effects of migration)? The population size would
A. begin to shrink immediately.
B. stabilize immediately.
C. keep growing indefinitely, but at a slightly lower rate.
D. increase for 2 - 3 generations, and then stabilize.
E. increase for 2 - 3 generations, and then shrink.

14. The age structure diagram to the right is most likely to represent
a(an) _________nation. (Sorry folks -- can't reproduce the graph here...click Answers to check!)
A. African
B. Asian
C. Middle-eastern
D. Latin American
E. European

15. Crop varieties developed as part of the "Green Revolution" have several characteristics that have contributed to increasing grain yields. What one of the following characteristics is important in allowing them to be so high yielding?
A. Their high levels of genetic diversity.
B. They can tolerate dry conditions without irrigation.
C. They yield well without additional fertilizer inputs.
D. Their flowering is very sensitive to changes in daylength.
E. They are dwarf plants that allocate more carbon to grain than to vegetative parts.

16. Before the green revolution, most increases in global agricultural production were caused by increases in cultivated acreage. Since the green revolution began in the 1940's,
A. increases in cultivated acreage have remained the main cause of global increases in production.
B. increases in cultivated acreage have continued to contribute to global increases in production, but have been less important than changes in crop varieties and agricultural practices.
C. total global cultivated acreage has declined steadily.

17. Which statement about total global grain production matches reality? Total production is currently
A. declining, as it has been since 1990.
B. increasing at essentially the same rate that prevailed from 1950 - 1980.
C. increasing twice as fast as human population is increasing.
D. increasing, but more slowly than it did between 1950 and the 1980's.
E. increasing faster than it did between 1950 and the 1980's.

18. What does the figure to the right represent? The trend in (Again, sorry -- can't put the figure in this web version -- just be sure to review the handout from class that includes these figures, and see Ag Trends.)
A. global irrigated acreage (total, not per capita).
B. global grain acreage (total, not per capita)
C. global grain acreage per capita.
D. global inputs of fertilizer per hectare.
E. global inputs of pesticides per hectare.

19. Which one of the following agricultural practices is most directly associated with all of the following: (1) large "dead zones" at the mouths of many rivers, including the Mississippi River; (2) fossil fuel intensity; (3) degraded soil structure and inherent fertility; and (4) "blue baby syndrome" (caused by production of methemoglobin in response to a water contaminant).
A. Use of broad-spectrum, non-persistent pesticides
B. Heavy application of phosphorus fertilizer
C. Heavy application of nitrogen fertilizer
D. Use of narrow-spectrum, persistent pesticides
E. Use of broad-spectrum, persistent pesticides.

20. Yields of corn per hectare in the US have increased tremendously in recent decades. Over this time, the energy efficiency of US corn production (the ratio of energy contained in the harvested corn to energy put into its production) has
A. doubled.
B. increased, but only by a small amount.
C. decreased.
D. remained the same.

21. If you wanted to increase input of nitrogen into your garden without using inorganic fertilizer, what kind of plant would make the largest contribution of fixed nitrogen?
A. Potatoes
B. Corn
C. Wheat
D. A legume

22. "Nonpoint" sources of water pollution are sources that
A. do not have important influences on water quality.
B. enter rivers through pipes, such as from industrial sources.
C. have no mission (there is no point to their existence).
D. access water through numerous and diffuse routes.

23. Use of pesticides in agriculture has increased greatly during recent decades. During this time, crop losses to pests, on a percentage basis, have generally ____________, compared to pre-pesticide levels.
A. dropped by about 10%
B. dropped by about 50%
C. increased by about 50%
D. remained about the same

Consider the following two scenarios for farm management when answering questions 24 to 26. Do not make assumptions about farming practices other than those described in the scenarios! Answer each question with "A" or "B," depending on which scenario is the appropriate choice.

Scenario A. Fields are planted with wheat every year. After the grain is harvested, the straw is baled and removed for sale. In the fall, fields are plowed and then fertilized with the maximum dose of inorganic fertilizer generally recommended for fields in the area. Fields are sprayed with herbicide in the fall and again in the spring so that weeds don't grow in them.

Scenario B. Fields are planted with wheat every other year, and with a legume in alternate years. After the grain (or seeds, for the legume) are harvested, the residue is left on the fields and cows are put on the fields to eat the residue. Fields are plowed in the spring, and inorganic fertilizer is applied in some years, depending on results from soil testing. Quantities applied are based on test results.

24. Under which scenario would soils be expected to contain more humus?
25. Under which scenario would you expect nutrient retention in the soil to be highest?
26. Under which scenario would the need for inorganic fertilizer increase more from year-to-year?

27. Where would you expect to find the highest concentration of a persistent pesticide (or its residue), such as DDT (or its breakdown product, DDE)?
A. Grass in a pasture
B. Insect that eats the grass in the pasture
C. Milk of cow that grazes on the grass in the pasture
D. Milk of woman who drank the milk and ate the meat of the cow that grazed on grass in the pasture

28. The term that best describes the phenomenon behind your choice of answer for the question just above (number 27) is
A. mineralization
B. immobilization
C. biomagnification
D. bioremediation

29. Globally, we lose an average of 30 to 48% of the crops we produce because of
A. pests and diseases.
B. excessive soil erosion
C. natural disasters.
D. drought
E. nitrogen saturation.

30. According to OSU's Sustainability Coordinator, Brandon Trelstad, which energy efficient technology will OSU's "New Energy Center" use to modernize the steam heat system on campus? (Can't give web notes link for this guest lecture -- click on Answers to find out!)
A. Wind turbines
B. Combined heat and power (CHP)
C. Fuel from biomass
D. Greenhouse gas absorption system (GGAS)

31. Of all the grain grown in the US, the largest percentage is
A. lost to pests.
B. exported to lesser developed nations.
C. used to manufacture ethanol.
D. used to feed livestock.
E. used to feed US citizens directly, as grain and products made from grain, such as bread.

32. Which one of the following is most likely to force a decreased reliance on chemical pest controls, not just in the US, but globally, in the future?
A. Environmental concerns about nontarget effects of pesticides.
B. Consumer concerns about decreased feedback regulation.
C. Farmer and consumer concerns about health effects associated with pesticides.
D. Pest resistance to pesticides (the "evolutionary arms race").
E. Evidence that some pesticides are hormone mimics ("gender benders").

33. Which one of the following increases the need to apply fertilizer in agriculture, causes silt build up in streams and reservoirs, and increases crop's vulnerability to drought?
A. Excessive soil erosion.
B. Excessive use of insecticides.
C. Reliance on relatively few crop varieties
D. Populations being smaller than carrying capacity.
E. Changed energy efficiency of agricultural production.

Consider the following in answering questions 34 and 35. A farmer grew corn every year on his/her fields for 10 years, and relied heavily on chemical insecticides to control insect pests in those fields. The farmer decided to not use the pesticides this year, as he/she became concerned about their economic, ecological, and human health costs. However, the consequences were not good - more of the corn crop was lost to insects this year than before he/she began using pesticides in the first place!

34. Which one of the following actions might have reduced the severity of crop losses to pests in this first pesticide-free year?
A. Irrigate more heavily than usual
B. Fertilize with more nitrogen and less phosphorus than usual
C. Plant the corn without plowing or cultivating the fields in advance
D. Plant a crop other than corn
E. Fertilize with less nitrogen and more phosphorus than usual

35. Why were the farmer's losses worse in the first pesticide-free year than they were before he/she began using pesticides 10 years ago?
A. Secondary pests had all been killed.
B. Pesticide exposure turned the corn pests into "super bugs," which ate more than usual.
C. Populations of predators of the pests had been diminished by pesticide exposures.
D. Pesticides enhanced negative feedback systems so losses to pests spiraled out of control.
E. Pesticide exposure caused mutations in the corn, which weakened its defenses against pests.

36. Which of the following federal agencies manages the most land in the US?
A. US Forest Service
B. US Fish and Wildlife Service
C. National Park Service
D. Bureau of Land Management

37. An "increaser" is a(an)
A. insect that becomes increasingly pesky after pesticides are used.
B. plant whose abundance increases as grazing increases.
C. plant whose abundance decreases as grazing increases.
D. insect population whose genetic resistance to pesticide increases after pesticide is used.
E. Plant whose abundance increases as grazing decreases.

38. What is an "AUM" in the context of livestock grazing?
A. American User Mission
B. American Unit Mitigator
C. Animal Usage Metric
D. Animal Unit Month
E. Available Usage Monitor

39. A stream flowing through a heavily grazed pasture will probably have
A. dense shrub cover along its margins, since cattle don't eat shrubs.
B. almost no silt covering the naked gravels on its streambed.
C. cooler water temperatures than expected for its location.
D. relatively low levels of dissolved nitrogen in the water.
E. relatively low levels of dissolved oxygen in the water.

40. Rates of soil erosion (in tons of soil per hectare per year) from agricultural lands in the US are, on average,
A. greater than erosion rates anywhere else in the world.
B. lower than those being sustained anywhere else in the world.
C. higher than those that prevailed during the "Dust Bowl" of the 1930's.
D. enough to deplete our topsoil resource by 50% every year.
E. no problem; no losses exceed rates of soil formation.

41. Which one of the following statements concerning use of irrigation in agriculture is true?
A. When there is competition between farmers and cities for water, farmers usually win.
B. Expansion of irrigated acreage in the future will be easy, because many major aquifers have yet to be utilized.
C. Most irrigation systems are very efficient in their use of water.
D. Irrigation has been very important in allowing increases in crop production over recent decades.

(Click on Answers to jump to the key for this exam, on Final Exam to move to that exam, on "Contents" (below) to return to the master Table of Contents for this BI 301 home page, or click "navigate" here for reminders on how to move within and among these documents.)

This page is maintained by Patricia Muir at Oregon State University. Page last updated Nov. 12, 2008.