Homework 1: Environmental Ecology (100 points)

Each question is worth 15 points, unless otherwise stated

Due: Tuesday, August 14th, 2007

This assignment must be typed, except for the drawing (which may be done by hand).

  1. Explain how optimal foraging theory relates to ecological fitness and natural selection. (10 points)
  1. While walking down at the Goleta Slough, you notice that egrets and blue herons have very long legs. Assuming that these birds are descendants of birds with shorter legs, offer a hypothesis for the long leg phenotype that is consistent with optimal foraging theory. (Note: you do not need to look this up or even provide the correct reason, just a hypothesis that makes logical sense). Explain your reasoning.
  1. Describe how you would test your hypothesis from question #2. What are the weaknesses of your test?

The following questions refer to the supplemental reading Tilman et al., "Agricultural Sustainability and Intensive Production Practices" (Available on the course website. You must have Acrobat Reader to open it- if not print it from the ES lounge before the weekend).

4.  Draw a feedback loop of the interaction between pesticides and pathogens described in the “Disease and Pest Control” section of the article. The reader should be able to understand the interaction just by looking at your diagram. Is the feedback positive, or negative? Explain.

  1. According to the article: Insects often evolve resistance to insecticides within a decade. Resistant strains of bacterial pathogens appear within 1–3 years of the release of many antibiotics. Offer a plausible reason, based on natural selection, why bacterial pathogens become resistant more rapidly than insects.
  2. Outline the strategies that the authors offer for: increasing nutrient and water use efficiency, maintaining soil fertility, and managing diseases/pests on agricultural land.
  3. Following a discussion of hypoxia in the Mississippi River drainage, the author claims: “Current incentives favour increased agricultural production at the expense of ecosystem services.” Explain clearly what the author means by this statement. How could ‘incentives’ be changed to prevent this case of hypoxia from occurring? Think of an original example that illustrates the concept embodied in this statement.