BI301 MIDTERM EXAM 2013


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 in the questions below to jump to a place in the lecture notes where that topic was addressed (note that some topics are discussed in more than one place; I try to give a link to the primary place!).

(Sorry that the formatting in some of the answer choices is a little wacky in this web version! Also, figures -- graphs -- don't show up here.)

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BI301 MIDTERM EXAM 2013

NAME:__________________________ Total points: Fill in your answers on the computer scan form - use pencil. Please be sure to put your name on this first page! Good luck!!

80 Points (2 points each question)

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

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 had significant impacts on Earth's ecosystems, but will 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 parameter 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 (ignoring immigration)?

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 (unfortunately, I can't seem to make this show up as a table -- the column headers are given in the first row, then corresponding data for each nation are listed below those under "A," "B," and so on; I've separated items in each row with *** to clarify the breaks between them) to answer questions 7 - 9:

Nation ***Population (millions) ***Natural rate of 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 ***2.4 ***30 / 12

D.***314 ***0.5 ***1.9 ***20 / 13

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-2012?

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 below. (The figure does not show up, but the X-axis represented time and the Y-axis represented numbers of people in the population. The curve starts out increasing slowly with time, then increases more steeply, the rate of increase then slows, and the curve levels off at about 10,000 people.)

11. The population growth curve illustrated in the figure 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 (in 2013), and remained at that level, what would happen to India's population size (ignoring effects of migration)?

A. It would begin to shrink immediately.

B. It would stabilize immediately.

C. It would keep growing indefinitely, but at a slightly lower rate.

D. It would increase for 2 - 3 generations, and then stabilize.

E. It would increase for 2 - 3 generations, and then shrink.

14. The age structure diagram to the right (doesn't show up here, but was basically columnar -- similar proportions of young people as of older people) is most likely to represent a(an) _________nation.

A. African

B. Asian

C. Middle-eastern

D. Latin American

E. European

15. Which one of the following characteristics of "Green Revolution" crop varieties 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 usually 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.

The following two questions refer to the figure on the right (should be familiar, eh? [That comment was because it was the same figure as had showed up on a recent quiz, and most people missed the answer then. The figure showed time on the X-axis with one line ("Line 1") sloping basically down over time and the other ("Line 2") sloping basically up over time.)

17. What does Line 1 on the figure to the right represent? The trend in

A. per capita land area planted to grain

B. total land area planted to grain

C. total grain production

D. per capita fertilizer application

18. What does Line 2 on the figure to the right represent?

A. per capita land area planted to grain

B. total land area planted to grain

C. total grain production

D. per capita fertilizer application

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) likely "fertilization" of forests with unknown consequences?

A. Use of broad-spectrum, non-persistent pesticides

B. Expanded use of irrigation

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. "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 purpose (there is no point to their existence).

D. access water through numerous and diffuse routes.

22. Use of pesticides in agriculture has increased greatly over 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

23. Globally, we lose an annual 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.

24. 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").

Consider the following two scenarios for farm management when answering questions 25 to 27. 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.

25. Under which scenario would soils be expected to contain more humus?

26. Under which scenario would you expect nutrient retention in the soil to be highest?

27. Under which scenario would the need for inorganic fertilizer increase more from year-to-year?

Consider the following in answering questions 28 and 29. 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!

28. Which one of the following actions might he/she have taken to reduce 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

29. 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.

30. What is stored in the "doomsday vault" deep in the Norwegian permafrost?

A. Radioactive waste

B. CO2 captured from coal-fired power plants

C. Seeds of hundreds of varieties of agricultural crops (fruits and vegetables and grains)

D. Toxic pesticide wastes

31. Of all the grain (grain, not just corn) 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 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

33. 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

34. An unfenced stream flowing through a heavily grazed pasture will probably have

A. dense shrub cover along its margins.

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.

35. Which one of the following claims related to livestock production on public lands in the western US is true?

A. An EPA survey indicated recently that streams and riparian areas on grazed lands are in the best condition they've been in for over 100 years.

B. Approximately 50% of US beef production comes from animals that grazed for at least part of their lives on public lands.

C. Federal agencies that lease land for grazing profit greatly from the fees that they charge for grazing; that is, they earn significantly more money from the leases than they spend to administer them.

D. Livestock cause cover of "biotic crusts" to increase, because their manure fertilizes the species that comprise the crusts.

E. Livestock grazing is implicated as one of the leading causes in the western US for the listing of species as Threatened or Endangered.

36. 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

37. 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 most 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.

38. Farmer Jones is puzzled. His/her fields are covered with a whitish crust, and the soil is quite moist, yet the plants look like they are wilting! Farmer Jones' land is located in an area with a very dry climate year round, and he/she irrigates heavily. Which one of the following is the most likely cause of the white crust on the soil and the wilting plants?

A. Fertilizer residue remaining on the soil surface, because Farmer Jones uses too much.

B. Soil salinization

C. "Biotic crusts" of algae and lichens, which grow well because the fields aren't grazed.

D. Ash left over from the eruption of Mt. St. Helens volcano in the early 1980's.

E. DDT residues

39. Which one of the following actions would be least effective if you wanted to decrease water use in your irrigated farming system?

A. Use computers to deliver a set quantity of water on a set schedule.

B. Irrigate only during the cooler parts of the day.

C. Convert from overhead to dripper irrigation systems.

D. Transport water in cement-lined canals rather than in unlined canals.

E. Switch to growing crops that are relatively non-water demanding.

40. If a food is labeled as "100% organic," its constituents should have been produced without

A. use of fossil-fuel driven machines.

B. supplemental water.

C. use of biological control agents against diseases or pests (e.g., ladybugs to eat aphids).

D. use of synthetic organic pesticides.

E. addition of any source of fertility to soils, including organic matter (i.e., compost).

(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 Oct 27, 2013.

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