Yamane and Gilman Worksheet

*I chose to read the “effects of body temperature on growth rates” result section of the Yamane and Gilman (2009) paper “Opposite responses by an intertidal predator to increasing aquatic and aerial temperatures”.

*Background. What information do the authors tell you to set the stage for their question(s)?

-Yamane and Gilman provide information regarding the effects of air and water temperature on the growth and feeding rates of Nucella ostrina.  Specifically they note that increased air temperatures reduce growth rates in these snails, and that increased water temperatures actually increase the feeding rates or “predation” rates in these snails (Yamane and Gilman 30).  They also note that these differences do not occur “linearly,” but instead occur at certain check point temperatures related to the physiological tolerances of these snails (Yamane and Gilman 31).  In the introduction, Yamane and Gilman also discuss how climate change is a very significant and well established variable in affecting the declination or general change of animal populations, and often even more so for predatory animals (Yamane and Gilman 1).  

* Question. What question do the authors ask?

-What environmental air and water temperature conditions create favorable or unfavorable conditions for Nucella ostrina?

*Method. What experimental design did they use to answer that question?

-This experiment was designed by Yamane and Gilman as a test of control group snails in their natural habitat versus experimental group snails.  The experimental snail groups were subjected to differing water and air temperatures to mimic the submersion and emersion conditions experienced by Nucella ostrina in their natural beach and saltwater habitats with rising and lowering tides.  Then Yamane and Gilman observed and recorded the growth and feeding rates of these snails in different air and water temperature conditions to determine if these artificially produced environmental variables had any noticeable and or significant effects on the growth and feeding rates of these snails.     

*Observation. What did they observe? (What is the result of their study?)

- Yamane and Gilman observed that higher air emersion temperatures, specifically beyond a certain cut off point above Nucella ocarina’s natural cellular temperature tolerance, causes the growth rates of these snails to significantly decrease to an unhealthy and worrisome level for these snails (Yamane and Gilman 30, 31, 32, 33).  

*Conclusion. What do they conclude from their observations?

-Yamane and Gilman concluded that a climate change which increased the natural coastal air temperature in the areas inhabited by Nucella ocarina could cause a significant decline in the health and population of these snails, but that a more likely simultaneous natural increase or change of both air and water temperatures would cause an essentially unpredictable result for intertidal species based just on this data alone (Yamane and Gilman 33, 34).  So Yamane and Gilman feel that this data serves as only a primary information base supporting their hypothesis that climate change can have effects on intertidal species, but that a precise projectable rate of temperature increase having such effects on precise species change is essentially undeterminable from the data produced in this study alone (Yamane and Gilman 34).  Therefore, they believe further more localized and precise studies must be done in order to make any specific conclusions or predictions regarding future onslaughts of climate temperature changes having any specific effects on specific intertidal species (Yamane and Gilman 34).   

*Was it easy to find the answers to these questions?

-I felt that it was fairly easy to find the answers to these questions in the results section, yet I was a little confused by what I perceived as the overlapping of the background information and observations when both of these were suppose to be found within the results section.  It seems to me that the background information should have really come from the abstract and introduction, not the results section.  But maybe this is just a misunderstanding of these terms on my part.