Practice AP Environmental Science questions on biodiversity levels, species richness, habitat comparisons, ecological benefits, and resilience after disturbance.
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.
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.
Figure 1. Percentage of Nonnative Plants and Average Number of Individual Spiders and Insects
Figure 2. Chickadee Population Average Growth Rate and Percentage of Nonnative Plants
Respond to parts A, B, C, D, E, F, G, and H, and all subparts.
Based on the data in Figure 1, identify the number of spiders per sample at 25\% nonnative plants.
Based on the data in Figure 1, describe the trend in the number of insects per sample in relation to the percentage of nonnative plants.
Insect biodiversity is important to maintain ecosystem health. A group of students was interested in learning about factors that affect ant biodiversity. They located two study sites near their school: a frequently mowed urban park and an unmowed grassland. The students used traps designed to collect ants. They loaded 10 of these traps with the same food and placed them randomly at different locations within each site. Students collected the traps after 24 hours and counted the number of different ant species in each trap to determine species richness.
Identify a likely scientific question for the students' investigation of ant diversity.
Identify the dependent variable in the students' investigation.
The data from the student investigation of ant diversity are shown in the following table. An "X" in the table indicates that the species was present at that site.
Ant Species Present in an Urban Park and Unmowed Grassland
Explain why the ant community of the unmowed grassland would be more likely to recover from a disturbance, such as a flood or fire, than the ant community in the mowed urban park would.
Explain how the results of the investigation could have been altered if students had measured ant biodiversity at a paved playground rather than in the grassland.