In a pond ecosystem, mosquito larvae feed on photosynthetic algae. Other larvae, such as dragonfly larvae, feed on the mosquito larvae. The dragonfly larvae are, in turn, consumed by fish, which can be preyed upon by raccoons. How many different organisms in this ecosystem get their energy from the food they consume? 1. One 2.TWO 3.Three 4.Four

INTERPRETING DATA Scientists estimate that only 10 percent of the energy present at each level of the food chain is available to the next level. Scientists also estimate that only 1 percent of the light energy from the sun that reaches photosynthetic organisms is converted to chemical energy during photosynthesis. Use this information and the two food chains below to answer the questions that follow. Food chain A Human vegetarians Food chain B Human meat eaters Cattle Read each question, and write your answer in the space provided 1. Assume that 1 million kilocalories (kcal) of energy from the sun is available to the autotrophs in the food chains above. Determine the amount of energy that will be available at every level of each food chain.

Do larval mosquitos or adult mosquitos have more nutritional value in the context of a food chain? Why?

Where on a food web would you typically find humans (near the bottom with the producers, at the top with carnivores, or somewhere in between?