Caretakers versus Exploiters: Impacting Biodiversity in the Age of Humans

Teaching Activities and Strategies

Statistics quantifies the world. I want my students to understand and apply the key statistical concepts outlined by the College Board in the AP Statistics course and exam description. I also want my students to experience as many aspects of the statistical processes, from experimental design, sampling, data analysis, inference, and communicating results. Many of the examples and practice problems used in statistics classes are based on published journal articles and studies. Student understanding of statistical concepts in relation to the context of a given situation is emphasized throughout the course. These sample activities will have students practice interpreting the methods and results based on data in existing studies regarding domoic acid along the California coastline. A culminating project I have planned include having students investigate seafood eating habits among their peers and families in our community and developing media to raise awareness of seafood toxicity in the local community. Potential field trips to local coastline to conduct sampling would depend on funding for transportation and coordination with local and state agencies.

Activity: Interpreting Correlation

California sea lions are regularly exposed to domoic acid through their diet which poses exposure risks to developing fetuses of pregnant sea lions. In the 2018 study “Domoic acid in California Sea lion fetal fluids indicates continuous exposure to a neuroteratogen poses risks to mammals” Lefebvre et al. measured domoic acid levels in fetal samples of California sea lions.

Domoic acid levels are quantified using enzyme-linked immunosorbent assay (ELISA) kits and using Liquid Chromatography Mass Spectrometry (LC/MS-MS) methods. ELISA tests are more sensitive to detection than LC/MS-MS methods, but using multiple testing types can help confirm presence of domoic acid in samples.

A total of ten fetal fluid samples are analyzed to detect levels of domoic acid using both ELISA and LC/MS-MS methods. Linear regression of domoic acid levels quantified via ELISA and LC/MS-MS on the ten samples results in a p-value of  and an R-square value of 0.69.

Questions

1. Is there a significant relationship between the quantified values of domoic acid using ELISA versus LC/MS-MS? Explain how you know.
2. Compute the correlation coefficient and interpret the value in the context of the problem.
3. Interpret the R-square value in the context of the problem.

Activity: Interpreting Confidence Levels

The Marine Mammal Center in Sausalito, California, works to rescue California sea lions stranded on central California beaches suspected of domoic acid poisoning. Using the data collected from 2010 to 2013, a 95% confidence interval of 64  21 sea lions per year admitted to the Marine Mammal Center is constructed to provide insight on the number of expected stranded sea lions due to domoic acid poisoning each year.

Questions

1. What is the mean number of California sea lions stranded on beaches between 2010 and 2013?
2. Identify the margin of error. What is the range of expected California sea lions each year?
3. In 2014, there 229 California sea lions were treated for domoic acid poisoning at the Marine Mammal Center. Was this number expected based on the confidence interval? What does this tell you about the amount of domoic acid in along the central California coastline in 2014?

Activity: Errors in Sampling – Dungeness Crabs

Using the example of domoic acid testing in Dungeness crab at the California Department of Public Health Students will examine the sampling techniques currently used in California to measure levels of toxins in seafood supplies and the surveys given to patients of suspected seafood poisoning used to determine whether government actions are needed to maintain a safe food supply.

Prompt: Health officials are testing domoic acid levels in Dungeness crabs from San Francisco Bay. Domoic acid is a neurotoxin that causes Amnesic Seafood Poisoning (ASP), which can cause memory loss and death If levels of domoic acid are above 20 mg/kg in the Dungeness Crab, the health officials issue a warning and crab fishing in San Francisco Bay must stop and sales of crab is banned. If levels are below the accepted amount, crab fishing can continue.

Questions

1. Identify the parameter and population.
2. Write the null hypothesis and alternative hypothesis.
3. What implications are there if there is a no warning, but levels of domoic acid are above the safety threshold? What type of error is this?
4. What implications are there if there is a warning, but levels of domoic acid are below the safety threshold? What type of error is this?

Project: Seafood Safety in the Local Community

Based on the responses to the questions from the previous activities, students will take their understanding of sampling and address the issue of seafood safety in the local community. Students will work in groups of 3 to 4 students to investigate the community’s awareness of seafood toxicity. Each group will be assigned a specific species of seafood currently monitored for domoic acid, such as Dungeness crab, clams, mussels and conduct a survey to gather information regarding the proportion of students aware of seafood toxicity and how many have recently eaten that particular type of seafood. Using this information, students will use the data to estimate what proportion of students at our school are aware of seafood toxicity and the proportion of students and their families that eat the species of seafood. They will then create visual media in the form of a poster, image, or video, that communicates the danger of domoic acid and how to minimize risks through safer seafood preparation and consumption methods. Groups will communicate their findings in writing, present their work in class to their peers and potentially other faculty members and community members.