Questions from group GLOBAL presentations. Answer six of the following questions, not including the one submitted by your group (1.5 points each, 9 points total).

1. What is the most cost-competitive renewable energy resource discussed in class (circle the best answer):

a. Solar

b. Hydroelectric

c. Biomass

d. Wind (although I accepted hydroelectric - old dams are cost-competitive)

2. Which of the following chemicals are thought to contribute to global warming (choose all that apply)?

a. Methane

b. Argon

c. Carbon Dioxide

d. Ozone

e. Water

3. List one benefit and one risk of genetically modified crops (GMOs) to the environment.

Benefits: higher yield per acre, tolerance for various abiotic conditions, insertion of genes to protect crops or supply vitamins in food.

Risks: they could become invasive, rapid resistance of pests, loosing a new species into environment, could be available only to affluent nations or large farms.

4. List one benefit and one risk of water privatization.

Benefit: clean water becomes available, private companies may be more efficient than municipalities

Risks: water may become too expensive for poor, corruption, water exported, industry not accountable to citizens, ignores local control

5. List two potential environmental problems stemming from invasive species.

Loss of biodiversity, altered abiotic conditions, kill native flora and fauna, and others

6. How does the reproductive rate of a species affect its success as an invasive species?

A high reproductive rate allows a species to produce lots of offspring. Many invasive species with high reproductive rate are r-selected, so in their native habitat, there is also lots of mortality. However, in a new environment, where mortality factors are absent, a high reproductive rate allows an invasive species to outgrow native populations, consuming resources more quickly, and ultimately adversely affecting the native species.

7. In one sentence, describe one reason why trees are a vital part of any one of the following biogeochemical cycles: hydrologic, nitrogen, or carbon.

Trees are essential in moving, transporting, and transforming nutrients through food webs. This includes the conversion of carbon dioxide to carbohydrates, and nitrate to protein. These new organic forms then become available to other species. Trees as a carbon sink are also important in mediating carbon dioxide emissions caused by burning fossil fuels. As for hydrology, trees help keep that cycle going by the process of transpiration, which is essential for them to help bring nutrients up from their roots, but has the added ecosystem benefit of moving water from the soil to the atmosphere.

8. What is one global implication to the problem China has in dealing with its grain production?

If China cannot produce enough grain to feed its population, it will have to enter the global grain market. A high demand from them could cause economic chaos, drive prices up and result in shortages in many nations that may already have trouble feeding their populations. In addition, China may decide to convert more marginal land to agriculture, causing further desertification, with the resulting effect of more giant dust storms, which affect many neighboring and distant countries.

9. List two advantages of biodiesel as an energy source.

Biodiesel is renewable, it reduces dependence on foreign oil, it produces fewer emissions and less soot, and it biodegrades faster than fossil fuels.

10. What is the major reason for the high population growth rate in the United States as compared to the lower rates found in other developed countries?

In a word, migration. Plus the high TFR of immigrants once in the states.

11. List two environmental problems that currently have negative impacts on food production and world hunger?

Soil erosion, desertification, salinization, water shortages, global climate change, pest resistance, and more.

12. In one sentence, describe the relationship between eutrophication and hypoxia.

Eutrophication leads to algal blooms, which can cause hypoxia, or oxygen depletion, as the algae die and settle to the bottom of water bodies and bacteria use up the oxygen decomposing the algae.

Questions from Lecture and Textbook

13. What is the pesticide treadmill, and how is it related to natural selection (5 pts)?

Pesticides are used and some individual pests survive. If those pests survived because of some mutation they possessed, which conferred resistance to the pesticide, then when they reproduce, some or all of their offspring will also have that mutation. Then, a greater percentage of the population will be made up of resistant individuals, since they have higher fitness in that environment. So the farmer must spray higher doses of that pesticide, which selects even more strongly for that resistant form. Soon, the pesticide becomes less effective or ineffective as the mutation spreads via natural selection. The evolved pest population thus grows rapidly. Now the farmer must use a different, more toxic pesticide, to which the pest population evolves resistance, and the farmer is on the pesticide treadmill. The resistance trait must be present in the population for natural selection to act on it, and those that possess trait will pass on more of their genes relative to susceptible individuals.

14. There are several agricultural practices that lead to soil degradation. What are two environmental consequences of these practices? What is a sustainable practice or method that would help alleviate at least one these consequences (6 pts)?

Consequences of soil degradation include soil erosion, salinization, desertification, loss of nutrients. There are sustainable practices that would alleviate one or more of these consequences, including strip cropping, intercropping, crop rotation, wind breaks, drip irrigation, and others.

15. Describe, specifically, how human actions have changed wetlands in the Mississippi R. delta, and how the changes have caused a loss of an ecosystem service to residents of New Orleans (6 pts).

Humans, specifically, the Army Corps of Engineers, have channelized the Mississippi R. and built levees around New Orleans. Channelization has caused a loss of sedimentation to the wetlands in the delta of the Mississippi. This is a renewal process necessary for wetlands that are subject to erosion from waves and land subsidence. The loss of wetlands has caused a loss of an ecosystem service, that of wetlands absorbing storm surges and large waves, which might have prevented some of the damage to New Orleans.

16. What are the primary and secondary pollutants that are relevant to photochemical smog, when and where is this type of smog a problem, and what can we do to reduce this type of smog (6 pts)?

Primary pollutants relevant to photochemical smog are NO and VOCs (hydrocarbons). Secondary pollutants are NO2, O3 (ozone), PANs (peroxyacyl nitrates). This type of smog is produced primarily in large urban areas that have lots of automobiles during the late mornings and early afternoons of warm, sunny days. We can reduce this type of smog by carpooling, telecommuting, using flexible work schedules, biking, riding a scooter(!), and using mass transit.

17. Briefly present evidence from two different areas of scientific inquiry (biology being one of them) that supports the conclusion of many scientists that Earth’s climate is changing rapidly (6 pts).

Biological evidence includes earlier flowering of many plants and emergence of various insects, poleward range expansions, decoupling of biological interactions, and bleaching of coral reefs. All of these things point to a warmer climate. Other evidence includes a rise in sea levels, recession of mountain and northern glaciers, thinning of polar ice caps, rapid rise of atmospheric carbon dioxide, warmer oceans and stronger storms, rapidly rising atmospheric temperatures, shorter winters and longer summers, and more.

18. Describe the pros and cons of either geothermal or hydrogen power (6 pts).

Geothermal pros include lower greenhouse gas emissions, renewability, low cost. Cons include potential salt corrosion, loss of hotspots, and geographic limitations.

Hydrogen power pros include never running out of H2, it's clean and nontoxic with no GH gas emissions, it's convenient, safe, and efficient, and has flexible applications. The cons are that it takes energy to produce H2, and this energy might come from fossil fuels, hydrogen emissions may have some effects on the upper stratosphere that we're not aware of yet, and it may be costly to convert our society and infrastructure to hydrogen power.

19. Discuss how predictions of global climate change within the next 20 years could or should change the way we think about drilling in ANWR (6 pts).

Global climate change is predicted to lead to warmer temperatures in the next 20 years. This could further disrupt ANWR's delicate ecosystem, which could be stressed so much that drilling could have much worse impacts than predicted now. In addition, the mere fact that climate is changing and burning fossil fuels is the likely cause of the rapidity of the change begs the question: why are we continuing to rely on fossil fuels at all? The rapid change in climate caused by rapidly rising greenhouse gas concentrations should make us think harder about alternative energies, not more drilling.

ON THE OTHER HAND, warmer temperatures will lead to rises in sea levels, possibly putting ANWR's coastline underwater. We then won't need to worry about effects of drilling along those edges of ANWR because it will now be offshore drilling. Of course, we'd need a pretty serious rise in sea levels for this to happen, but with drilling technologies the way they are, it may be that oil under the land can be reached from the sea. Offshore drilling is not without its environmental impacts, too, so we'd still need to be careful. Warmer temperatures might also lead to rapid loss, degradation, or disruption of ANWR's ecosystem, so then it won't matter what further disruption drilling causes. Wow, this sounds grim, maybe we ought to get out of the fossil fuel business now...

Return to CP's BIOLOGY 103 Page

Return to CP's Home Page