AGRON 405/505 Spring 2015
Problem Set 11
Due Tuesday, April 14, 2015.
Assigned April 7, 2015.
1. 12.1 in Campbell and Norman. Assume M = 40 W m−2 for both a human and a
mouse. Assume gv = gvs , where gv is the total water vapor conductance, and gvs is the
skin water vapor conductance. Assume that both a human and a mouse have body
and surface temperatures of 37◦ C.
2. Consider the following equation that relates metabolism (M), latent heat flux (λE),
and internal body temperature (Tb ) to the operative temperature (Te ) through the
boundary layer (gHa ), radiative (gr ), tissue (gHt ), and coat (gHc ) conductances (represented by gHr and gHb ).
(M − λE) =
gHr
cp (Tb − Te ) = g cp (Tb − Te )
1 + ggHr
Hb
(1)
(a) Draw a diagram that represents how gHa , gr , gHt , and gHc are “connected” in terms
of the flow path for heat leaving the body core and indicating which conductances
are in series or in parallel.
(b) What is the total conductance g if gHa , gr , gHt , and gHc are all 1 mol m−2 s−1 ?
(c) Which conductance should be 0.1 mol m−2 s−1 to maximize g if the other three
are 1 mol m−2 s−1 ?
(d) Which conductance should be 0.1 mol m−2 s−1 to minimize g if the other three
are 1 mol m−2 s−1 ?
3. 12.3 in Campbell and Norman. Assume a tissue conductance of 1 mol m−2 s−1 . Estimate coat conductance from Figure 12.4 in the text.
4. Read “Thermoregulation Keeps Creatures Cool in Hot Weather” on the course website.
This article appeared in the Ames Tribune.
(a) Give three examples of animal behaviors (not necessarily in the article) that allow
them to cope with hot weather.
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5. Read “Differences in Thermal Tolerance Among Sockeye Salmon Population,” doi:
10.1126/science.1199158.
(a) Define “aerobic scope.”
(b) The authors predicted that “migration distance... would exert the strongest selection pressure on aerobic scope.” Was this confirmed? See Figure 2.
(c) What is the name of the most challenging section of the Fraser River system?
(d) Define the variable Tp that is mentioned on page 112.
(e) Speculate what might happen if the water temperature at the river feature named
in Part 5c increases in the future.
(f) Which population of sockeye salmon appears to have the greatest tolerance for
climate change?
6. Read the section “Why does heat seem to bother (some) elites much less than the rest
of us?” in the “Elite Explainer” article on the syllabus.
(a) In general, is a bigger or smaller runner best able to deal with heat? Why?
(b) Name two things that happen as humans acclimate to heat and their sweating
efficiency increases, and why these changes are helpful.
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