SCIENTIFIC THINKING Researchers studied active and abandoned pika colonies at two sites (one in southeast Oregon and one in northwest Nevada) to understand how elevation might influence pika range (see Module 38.0 and Module 38.11). Sites were classified as old (no longer occupied) or current. How would you summarize the findings? Does this study support the hypothesis that pika ranges are shifting to higher elevations due to climate change? What are some limitations to describing patterns in nature as compared to doing a controlled experiment?

Verified step by step guidance

1. Examine the graph to understand the data presented. The y-axis represents the elevations of pika colonies in meters, and the x-axis represents two different sites: Hart Mountain, OR, and Sheldon, NV. The key indicates that red bars represent old (no longer occupied) colonies, and blue bars represent current colonies.
2. Observe the elevation ranges for both old and current colonies at each site. Note that at Hart Mountain, OR, the old colonies are at higher elevations compared to the current colonies. In contrast, at Sheldon, NV, the old colonies are at lower elevations compared to the current colonies.
3. Summarize the findings by stating that at Hart Mountain, OR, pikas have moved to lower elevations, while at Sheldon, NV, they have moved to higher elevations. This suggests a shift in pika ranges, but the direction of the shift varies by location.
4. Evaluate whether the study supports the hypothesis that pika ranges are shifting to higher elevations due to climate change. The data from Sheldon, NV, supports this hypothesis, but the data from Hart Mountain, OR, does not. Therefore, the support for the hypothesis is mixed.
5. Discuss the limitations of describing patterns in nature compared to doing a controlled experiment. In natural studies, there are many uncontrolled variables that can influence the results, such as differences in local climate, habitat, and other environmental factors. Controlled experiments allow for the isolation of specific variables to determine their direct effects, which is not possible in observational studies of natural patterns.