Biology Now, 2e

Caves of Death ■ 19

Leveling Up

(^13) What do you think? Insectivorous bats save the agriculture
industry billions of dollars each year because they eat insects that
damage crops. Other species of bats pollinate some crops. What
would you predict about crop yields in areas that are experiencing
heavy bat mortality from WNS? Does your prediction affect your
level of concern about WNS? Why or why not?
(^14) Doing science Although you are an expert on white-nose
syndrome in bats, you have been asked to contribute your
scientific expertise to understanding the fungal infection that
is decimating frog populations worldwide: Batrachochytrium
dendrobatidis, a.k.a. Bd.
a. Read the May 2013 National Geographic article on how Bd has
been spread around the world: http://news.nationalgeographic
.com/news/2013/13/130515-chytrid-fungus-origin-african
-clawed-frog-science.
b. The graph provided here, based on data from a scientific paper
published in 2013, shows that frog species with higher average
body temperatures tend to have lower Bd infection rates. It also
shows that, compared to males of the same species, females
tend to have higher average body temperatures and lower
Bd infection rates. Is this observational study descriptive or
analytical? Explain your answer.

0 10 20 30 40

Time body temperature is above 25°C (%)

10

20

30

40

50

60

Infection rate (%)

= Frog species 1

= Frog species 2

= Frog species 3

= Male

= Female

c. Propose a hypothesis to explain the results depicted in the

graph, and then identify a testable prediction from that

hypothesis. Design an experiment to test the prediction,

identifying your independent and dependent variables, the

control group, and the treatment conditions. Create a graph

to show the results you expect to find (1) if your hypothesis is

supported and (2) if your hypothesis is not supported.

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