After studying this section you should be able to address the following:

1. Define niche.
2. Would competition between animals or plants in the same ecological niche be more severe than between animals or plants that live side by side, but that are in two different ecological niches?  Explain.
3. What is the Competitive Exclusion Principle?
4. Imagine an age-structure diagram for a human population in which the diagram looks like an inverted pyramid.  Provide an explanation for such an age structure in a population.  Predict what the age-structure of the population will be after 50 years.
5. Do you expect the number of herbivores to be greater, equal to, or less than the number of carnivores in an area?
6. If you were the president of a developing country which had a rapidly growing population which of the following strategies to produce food for your population would you support and why?
• Use the land to graze animals and eat primarily an animal based diet
• Use the land to grow crops like wheat or rice, and eat primarily a vegetarian diet.
7. What determines the point at which an S-shaped (sigmoidal) growth curve levels off?
8. What types of selection pressures would contribute to the evolution of species that produce many and fast-growing offspring? few and slow-growing offspring?  Draw a survivorship curve that is typical of each of these types of species.
9. Why are producers the lowest level on a trophic pyramid?
10. If 100,000 kcal of energy is contained within the producers in an ecosystem, how many different trophic levels of consumers can be supported by those producers?  Explain how you arrived at your answer.