The Big Quiz

Fall 2002

Instructions: This midterm is worth 50 points (10% of your course grade) and will be due in class Tuesday, 10/22/02. No exceptions – late reviews will result in at least a 10% deduction. You may not consult any references or any other person while working on this review. Your signature at the bottom of the last page signifies that the work is yours alone and is pledged under the Honor Code. When you break the seal on the envelope you will have two hours to complete the review! Please print legibly; I can only grade what I can read! Alternatively, you may type your answers, but that doesn’t mean you can lengthen your answers. If you choose to type your midterm, turn in both the midterm and the typed answers, with your name on both.

For each question or part to a question, limit your answers to the space below each question, unless otherwise specified. Keep your answers within the limitations set forth in the question. If the question asks you to list something, list it – don’t write an essay! Any part of your answer outside of the space provided will not be graded.

Reminder: confine your answers to the space immediately below each question.

1. Define two of the following terms (4 pts – 2 pts each):

a. Ecotone: Transitional zone in which one type of ecosystem tends to merge with another ecosystem.

b. Biome: Terrestrial regions inhabited by characteristic types of vegetation and wildlife, determined by climate, and somewhat by latitude.

c. Biodiversity: Variety of different species within an ecosystem, genetic variability among individuals within a population, variety of habitats or ecosystems within a biome, or variety of functions within a community.

d. Gene pool: The sum total of all genes found in the individuals of the population of a particular species.

2. Match the biological polymer with it's monomer and it's class of compound (3 pts)?

a. DNA __A___ Nucleotide ___C__ Carbohydrate

b. Enzyme __C___ Simple sugar ___A__ Nucleic Acid

c. Cellulose __B___ Amino acid ___B__ Protein

3. Describe a simple model that can be used to assess environmental impact in developed versus developing countries (4 pts).

The model could vary, but it needed to be a model with well-defined parameters that could be used together to determine environmental impact, and be used also to compare developed vs. developing countries. The most common type, and what I had in mind when I wrote the question, was the model that uses population size or growth rate, per capita use of resources, and per capita impact of technology as a measure of environmental impact.

4. What do scientists need to know to determine rates of background extinction? How do we know if we're in the midst of a mass extinction (5 points)?

We need to know a couple of things to estimate background extinction rates. First, we need to know the total number of species and the average lifespan of species. This will allow us to calculate how many species, on average, go extinct over any time period (number of extinctions/decade/total number of species, for example). Alternatively, we could estimate background extinction rates by using data from the fossil record, by tracking the duration that individual species are found in rock strata, and how many disappear in any one layer compared to how many are found there. Both estimates lead to high bias, due to the extreme amount of error and variation involved in estimating the total number of species, their average lifespans, and the fossil record. We know if we're in a mass extinction if the current estimate is much higher than background estimates, and it is sustained at a high level (or increases). Our current estimates are so much higher than estimates of background rates, that even if we're off by large factors, the lowest current extinction rate estimate is higher than the highest estimate of normal background extinction rates.

5. List three root causes of environmental problems. For each, list two environmental problems that the root cause produces (6 pts)?

The five root causes, and environmental problems associated with them, are:

Poverty: overgrazing, habitat loss, land degradation, erosion, water shortages, loss of biodiversity, poor nutrition, overpopulation

Rapid population growth: waste, habitat loss, land degradation, erosion, pesticides, oil spills, air pollution, global climate change, extinction, etc.

Unsustainable resource use: waste, habitat loss, land degradation, erosion, pesticides, oil spills, air pollution, global climate change, extinction, etc.

Not including environmental costs: waste, habitat loss, land degradation, erosion, pesticides, oil spills, air pollution, global climate change, extinction, overfishing, toxic waste, etc.

Overmanagement and simplification of nature: habitat loss, degradation, erosion, biodiversity loss, others

6. What are life's support systems, and why may they, as a whole, be considered an artificial classification scheme? (5 pts).

The life support systems are the atmosphere, lithosphere, hydrosphere, and biosphere. Although each can be considered separately, the classification is artificial because, in reality, each is intimately connected with the others. These are systems because they are groups of related objects or forces (e.g., the hydrosphere includes all bodies of water, forms of water, and processes that move water).

Some students used energy from the sun, nutrient cycles, and gravity. While these are technically not systems, I did accept this answer for up to full credit (depending on the rest of the answer). These are somewhat artificial, too, in the sense that nutrient cycles depend on energy and gravity to drive the cycles.

7. List one preventative and one cleanup control to address one of the following pollution problems (4 pts):

a. ground-level ozone

Preventative controls include: reduce emissions from mobile sources and factories, switch to non fossil fuel energy sources, and others

Cleanup controls include: cleanup NO from emissions before they leave vehicle exhaust systems, plant trees to absorb pollutants, and others

b. greenhouse gasses

Preventative controls include: reduce emissions from mobile sources and factories, switch to non fossil fuel energy sources, and others

Cleanup controls include: plant trees to absorb carbon dioxide, and others

8. If the world warms up in the coming century, many things are predicted to happen. For two of the following resources or habitats, describe how one thing may change as temperature increases. Be specific (2 points each = 4 points).

a. Biodiversity: extinction of some plant and animal species, loss of habitats, disruption of aquatic life

b. Coastal habitats: rising sea levels, flooding of low-lying islands and coastal cities, flooding of estuaries, wetlands, and coral reefs, beach erosion, disruption of fisheries, saltwater contamination of coastal aquifers

c. Forests: changes in forest composition and locations, disappearance of some forests, increased fires from drying, loss of habitat and species

d. Human health: increased deaths from heat and disease, disruption of food and water supplies, spread of tropical diseases to temperate areas, increased respiratory disease, increased water pollution from coastal flooding

9. Select one type of grass-dominated biome and one type of tree-dominated biome (forest). Identify your choices. Compare the climates of those biomes, the predominant latitudes in which they're found, and the adaptations the dominant vegetation has to that climate (7 pts).

To receive full credit you had to describe the average annual climate conditions for both, or at least in a comparative way, and the range of latitudes in which they're found, either quantitatively or descriptively, such as near the equator or far from the equator. Finally, you had to list some adaptations that plants have for living in that particular climate. For instance, in dry, seasonal climates, broadleaf plants often lose their leaves once per year.

10. Select two biogeochemical cycles and discuss those chemicals' movement through three of four of Earth’s life support spheres. Use at least two processes and two forms of each chemical to illustrate the cycle, and list one means that humans are disrupting both cycles simultaneously (8 pts).

To receive full credit you had to identify two cycles and clearly relate the movement of those chemicals through three of four spheres (lithosphere, hydrosphere, biosphere, and atmosphere). I would've preferred if you all had identified forms associated with particular spheres (e.g., carbohydrates in biosphere and carbon dioxide in atmosphere for carbon), but not all of you did that. Processes had to be used to illustrate a change in form or movement between spheres or both. Finally, humans may disrupt BOTH cycles simultaneously by doing one thing - you needed to make that connection and not list disruptions separately.