SCIENTIFIC THINKING In 1954, workers at Michigan State University began spraying the elm trees on campus annually with DDT to kill disease-carrying bark beetles. In the spring of 1955, large numbers of dead robins were found on the campus. Observers thought perhaps the robins died after eating earthworms contaminated by DDT the previous spring. Suggest how scientists could have investigated the scientific validity of this idea.

Verified step by step guidance

1. Identify the hypothesis: The hypothesis in this scenario is that the robins died due to consuming earthworms that were contaminated with DDT.
2. Design an experiment: Set up a controlled experiment where two groups of robins are observed. One group is fed earthworms from areas where DDT was sprayed, and the other group is fed earthworms from areas without DDT exposure.
3. Collect data: Monitor the health and mortality rates of the robins in both groups over a suitable period of time to gather sufficient data on the effects of DDT-contaminated earthworms.
4. Analyze the data: Compare the health outcomes of the two groups using statistical methods to determine if there is a significant difference in mortality rates and health issues between the robins fed with DDT-contaminated earthworms and those that were not.
5. Draw conclusions: Based on the analysis, determine whether the initial hypothesis that DDT-contaminated earthworms caused the death of the robins is supported by the experimental data.

Key Concepts

Hypothesis Testing

Hypothesis testing is a fundamental aspect of scientific inquiry where researchers formulate a testable statement based on observations. In this case, scientists could propose a hypothesis that the robins died due to DDT-contaminated earthworms. They would then design experiments to collect data that either supports or refutes this hypothesis, allowing for a systematic investigation of the cause of the robins' deaths.

Ecological Impact of Pesticides

Understanding the ecological impact of pesticides like DDT is crucial for assessing their effects on wildlife. DDT is known to bioaccumulate in the food chain, meaning that organisms at higher trophic levels, such as robins, can suffer from toxic effects after consuming contaminated prey. This concept helps scientists evaluate the potential pathways through which DDT could harm bird populations.

Experimental Design

Experimental design refers to the planning of an experiment to ensure that it effectively tests a hypothesis. Scientists could design a study that includes control and experimental groups, where one group of robins is exposed to DDT and another is not. By comparing the health and mortality rates of both groups, researchers can draw conclusions about the relationship between DDT exposure and robin mortality.