This week’s lab focused on the thermoregulation and temperature regulations of organisms. Thermoregulation is defined as the ability of an organism to keep its body temperature within certain boundaries. The different temperatures of different ecosystems dictate the body temperature of organisms. Organisms that rely on external sources of energy to regulate their body temperature are considered ectotherms, and endotherms are organisms that rely on internally derived metabolic heat to control their body temperature. Factors, such as, size, shape, habitat, climate conditions, and presence of insulation also control how an organism regulates its body temperature. The significance of this lab is to see how environmental factors affect animal heating and cooling.
The main objective of this lab was to investigate a variable that could be controlled by heat. After choosing a variable, we were to create a testable hypothesis, and examine how fact our experimental animals took to heat and cool. For Part A, we were to create a cube out of aluminum foil, place it under a heat lamp, and record the temperature until it levelle off. The cube was placed under the heat lamp for 20 minutes without any changes in temperature, so we moved it 15 cm closer to the heat lamp to collect our data values. Part A of the lab allowed us to become comfortable in creating a test organism and recording temperatures for Part B.
What did you select for your study factor? Why is it interesting to scientists?
For our study factor of the temperature relations lab, we studied the thermoregulation in endotherms and ectotherms and how factors such as warming temperatures on an animal’s body effect insulation rates. This study factor is interesting to scientists because it allows them to examine the link between the two species and how climate change, which is an on-going issue, and a host of other factors, can potentially affect both species normal body temperatures.
How did you design the study to answer the question? What challenges did you encounter?
-Our study question focused on what type of organism, endotherm vs. ectotherm, would take longer to heat if the two types of animals were put under the same conditions. We created an animal that was most similar to a dolphin. The design plan was to create one organism to use in both trials. In one trial we would stuff the organism with a material, like paper or cotton balls, to act as an endotherm; we would then take out the material and conduct our ectotherm trial. At first, we created an organism that was made out of blue construction paper and aluminum foil, and held together with Elmer’s glue. This organism was uniform in shape and material, but we found it difficult to stuff with our paper towels, the chosen material for the endotherm. In the end, we recreated our organism giving it a more tube-shaped, elongated body. This allowed for the endotherm material to be easily put and removed into the organism.
The organism was placed 15 cm from the heat source for the first trial with the endotherm. After 3:29, we chose to move the organism 5 cm closer to the heat source because of a lack of change. After further analysis and discussion, we discovered that this was not abnormal characteristic for an endotherm. The trial for the endotherm lasted for a total of 20 minutes, and we took record of the temperature at every minute. At the end of 10 minutes, we removed the organism from the heat for another 10 minutes. These two intervals were done for each test organism and used to create heating and cooling curves.
What animal most closely represents your study animal in terms of thermoregulation (endotherm or ectotherm)? How did you design your animal to accurately reflect the proper thermoregulation?
The animal that most closely represents our study in terms of thermoregulation is an endotherm. Our constructed animal reflects this type of thermoregulation due to the cotton balls and tissue we utilized to test out our experiment. We used aluminium foil to construct the shape of a dolphin and stuffed the middle half of the animal with cotton balls in place of actual blubber, which is one of the mechanisms that keep them warm. This method confirmed our hypothesis that endotherms maintain a rather constant body temperature regardless of the fluctuation of outside temperatures, versus ectotherms, who depend on outside temperatures.
What did you find surprising about your results? How do your results inform our understanding of animal thermoregulation?
We found that the overall changes in temperature for both test organisms were the most surprising. The mean temperature for the endotherm was 28.68 ℃ which is only a 0.68℃ change in temperature from the initial temperature of 28.0℃. While conducting the experiment, we troubled with the lack of temperature change, but as we considered the prior information about endotherms this was no longer as shocking. Endotherms exchange heat more slowly with the environment and are well insulated; these organisms maintain a stable internal temperature—despite the fluctuations in temperature in their environment (Seebacher).
The ectotherm had a more drastic change in temperature. The initial temperature of the ectotherm was 27.0℃ and the average temperature was 29.85℃, and 2.85℃ change in temperature. This supports data and information found about ectotherms. These organisms exchange heat more rapidly with the environment and have little to no insulation. Ectotherms have very low metabolic rates, so they are unable to maintain a constant body temperature and it’s dependent on the environment for heat regulation.
Discuss how the findings in the article Shrinking dinosaurs and the evolution of the endothermy of birds relate to your own study on thermoregulation. As a science communicator, how might you relate the findings to a middle school student? A retiree?
What we found in the evolution of endothermy in dinosaurs article is that our results in comparison, pointed at the big picture of endotherms being a rather challenging species to pinpoint. While we were conducting our experiment, we were able to examine the metabolic cost and benefits of having a large sized body versus a small sized body. In the article regarding body size, it was stated that the starting size of larger bodied animals had a cheaper transition to endothermy versus ectotherms. Additionally, animals like dolphins manage to conserve enough heat so that their internal body temperature is higher than the temperature of the surrounding water. This phenomena ties in with the article and the discussion of dinosaurs having large enough bodies to be able to experience a shift in temperatures. Furthermore, as a science communicator, it is important to have information written in a way that is clear and successfully delivers one’s message. This way of communicating science is considered plain language, a term for communication that the audience can easily understand and use in future situations. One successful way this information could be related to a middle school student is through graphs. The article includes graphs, but some of these graphs would be considered difficult to interpret as they consist of hundreds of data points and an overwhelming amount of information. If these graphs were to be simplified into simple line graphs, scatterplots, or bar graphs, it would be more greater appeal and ease of reading to middle school students and other non-scientific audiences.
Reference: Seebacher, Frank. 15 June 2009. Responses to temperature variation: integration of thermoregulation and metabolism
in vertebrates. The Journal of Experimental Biology, Vol. 212, 2885-2891. doi:10.1242/jeb.024430
The introduction was completed by Nia Alston. Questions 1 and 3 were answered by Jayla Watkins. Alston also completed questions 2 and 4. Alston and Watkins completed the last question in collaboration along with creating the graphs and capturing the photos from experimentation.
The Eco 411 