Interpreting Graphed and Tabular Data

1. The use of DDT for malaria control stopped being funded by the World Health Organization (WHO) in the 1980s. The World Bank required a ban on DDT for developing countries seeking loans. At the same time there has been an increase in the resistance of the malarial parasite to the most common antimalarial drugs. Since 2001, WHO has allowed the spraying of DDT in Africa on interior walls to kill mosquitoes?

Review the graph in Figure 1 and information provided and then answer the following questions.

What is the independent variable?

Why was a bar graph selected to present these data? Could the authors have used a line graph?

Figure 1

Write a statement summarizing the results. Specifically address trends from 1972-1992, 1995-2000 and 2001-2004.

2. Review the experimental conditions for the monarch butterfly and milkweed experiment in Exercise 1.2. Recall that adult butterflies lay their eggs on milkweed plants and that the caterpillars that hatch feed on the milkweed leaves. Adult monarch butterflies are often infected by a protozoan parasite that affects their survivability and growth. Some milkweeds (A. curassavica) produce high concentrations of anti-parasitic compounds that reduce parasitic infections in monarch butterfly offspring.

Scientists hypothesized that infected monarch butterflies preferentially lay their eggs on milkweeds that reduce parasite infection (A. curassavica). In the experiment, the investigators measured the proportion of eggs laid on A. curassavica by infected and uninfected adult monarch butterflies.

If the butterflies showed no preference for the A. curassavica plants what would be the expected proportion?

The results of this experiment are shown in Figure 2. Do the results support or falsify the hypothesis? Explain your answer using the data presented.

In a second experiment scientists hypothesized that parasite. Infected caterpillars would consume a greater proportion of their diet from the anti-parasite (A. curassavica) milkweed. In the experiment, caterpillars were given the choice of feeding on milkweed leaves with high concentrations of anti-parasite compounds (A. curassavica) or another milkweed with low concentrations.

Figure 2

Figure 3

The results of the caterpillar feeding experiment are shown in Figure 3. Do these results support of falsify the hypothesis? Explain your answer using the data presented.