1.An expanse of beach measures 50 meters by 100 meters. In a one square meter grid a team of volunteers count 10 horseshoe crabs. Estimate the total number of crabs on the beach. What method did you use to estimate the population size? How could you make a more accurate estimate?

2. Compare and contrast the concepts of a food chain and a food web. Why are food webs a more realistic way of portraying ecosystems than food chains?

3. How does the amount of energy available change from one level of the ecological pyramid to the next level up? Why does this happen?

4. Describe the flow of energy from the sun through the following food chain.

Sun, flower, insect, snake, hawk What form is the energy in at each step? What process converts it from one form to another?

5. What is photosynthesis and where does it take place? Where does the energy for photosynthesis come from? What form is it in? How and in what form does a plant store the energy it receives from the sun?