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Do Grasshoppers Sweat?

A Surprising Case of Evaporative Cooling



Co Authors:

John G. Cogan
Department of Chemistry and Biochemistry
The University of Ohio
cogan.1@osu.edu

Emily Hill
Health and Rehabilitation Sciences
The University of Ohio

Henry D. Prange
Medical Sciences Program
Indiana University Bloomington

Abstract:

There are many adaptive and evolutionary behaviors displayed in an organism's use of water. Although students generally have a superficial understanding of the importance of water to life (i.e., without water life cannot persist), this directed case study aims to deepen their understanding.  The storyline is centered on the research of Dr. Henry Prange using the Schistocerca nitens species of grasshopper. The case examines organisms' efficient water use in respiratory, metabolic, and homeostasis mechanisms, which in turn are possible because of water's structure and properties. A PowerPoint presentation is included that summarizes the structural, emergent, and temperature-buffering properties of water and is used to supplement the entertaining examples of cooling mechanisms introduced in the associated videos, which make the case suitable for a flipped classroom. The case study handout is in a worksheet format that features application questions and small group problem-solving discussions. This case study was written for an introductory biology course, and could be used for majors and non-majors alike.

Objectives:
  • Compare and contrast different cooling mechanisms employed for survival, as well as provide examples (behavioral vs. physiological).
  • Define evaporative cooling and apply this definition to specific examples/predictions.
  • Identify the important properties of water that allow for evaporative cooling to occur (i.e., emergent properties of water).
  • Apply new information that is provided to answer questions about temperature regulation (i.e., ventilation, metabolism).
  • Interpret graphs and data and identify correlative and causal relationships.
  • Use scientific inquiry, deductive reasoning, and the data provided to come to conclusions.
Keywords: Water; emergent properties of water; homeostasis; evaporative cooling; grasshopper; adaptation; evolution; Schistocerca nitens;
Topical Area: N/A
Educational Level: High school, Undergraduate lower division
Formats: PDF, PowerPoint
Type/Method: Directed, Discussion
Language: English
Subject Headings: Biology (General)   Biochemistry   Science (General)   Physiology  
Date Posted: 4/30/2018
Date Modified: N/A
Copyright: Copyright held by the National Center for Case Study Teaching in Science, University at Buffalo, State University of New York. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

Teaching Notes


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Answer Key


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Supplemental Materials


The PowerPoint presentation below summarizes the structural, emergent, and temperature-buffering properties of water to supplement the examples of cooling mechanisms introduced in the pre-class videos. The podcast and article further below are also recommended.

  evaporative_cooling_sup.pptx
  Panting, Perspiration, and Puddles
This podcast features discussions of how we lost the fur of our primate ancestors in favor of sweaty skin and the peculiar ways in which some ectotherms stay cool. Podcast created by Science Friday. Running time: 16:52 min. Date: August 11, 2017.
  How Do Animals Keep Their Cool?
Humans are among the few mammals that sweat; other animals employ a whole host of mechanisms to keep cool. This article provides a brief look at how animals— including us—have evolved to beat the heat. Johanna Mayer, Science Friday, August 25, 2017.

Videos

The following video(s) are recommended for use in association with this case study.

  How Israeli Zoo Animals Cool Off in Summer
This video includes examples of zoo animals, primarily large mammals (endothermic), utilizing different behavioral mechanisms to cope with heat. Running time: 2:32 min. NTDTV, 2011.

  The Sidewinder Snake Slithers at 18 MPH
This video offers another unique example of a behavioral adaptation in a desert ectotherm. Running time: 3:09 min. Smithsonian Channel, 2015.

  Planet Earth—Season 1—Episode 5: Deserts
This video introduces multiple aspects of cooling (behavioral, evaporative, radiation) through specific mammal examples. Running time: 48:00 min. Produced by BBC, 2013. The 6:30 minutes from 12:30–19:00 in the video are the most relevant. This video is not currently open access, but is widely available from streaming services and libraries.




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