This assignment is worth up to 5 points extra credit. Read the source material below and then answer the questions, either by entering your answers into the text box, or by attaching a file. You do not need to re-write the questions, but please number your responses.
Diving Adaptations in Sea Nomads (HHMI Biointeractive)
“Enlarged Spleens Key to Diving Endurance of Sea Nomads” (Links to an external site.) (youtube video)
“The Secret To Deep Diving May Lie in the Spleen” (Links to an external site.) (NPR news article)
Questions:
1. What was the scientists’ main research question regarding the Bajau? Make sure to include the two competing hypotheses here. (Hint–this can be found in the Background Information section of the handout).
2. Why were the researchers interested in spleen size? How do the spleen sizes of the Bajau and the Saluan differ? Use data from the figure to support your response.
3. The scientists found that the difference in spleen size between the Saluan and Bajau populations remains significant even after accounting for other factors (such as gender, age, weight, height, and whether the individuals practiced freediving) through additional statistical analyses. The scientists also found that the spleen size difference between Bajau divers and Bajau nondivers is not statistically significant. In other words, Bajau nondivers generally still have larger spleens even though they do not do freediving themselves. Based on this information, explain why this supports the hypothesis that the difference is the result of natural selection.
4. The NPR article describes cultural changes occurring among the Bajau diving population. If the Bajau were to cease diving, what do scientists predict will happen to their spleen size?
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