AP Environmental Science Eng 1 D Describe Food Chains and Food Webs and Their Constituent Members By Trophic Level Questions

Chickadees are a K-selected species of bird that eat insects and spiders. Spiders consume insects, and many insects consume plants as shown in the following food chain.

$$\mathrm{Plants}\rightarrow\mathrm{Insects}\rightarrow\mathrm{Spiders}$$

Chickadee habitat includes forests and residential yards. Residential yards often contain nonnative plants, which do not naturally exist in an area, but were introduced by humans.

Scientists measured the average number of insects and spiders as related to the percentage of nonnative plants (Figure 1). The scientists also measured the chickadees' average population growth rate (Figure 2) to determine the impact of nonnative plants on chickadee populations.