In the early 1900s, many people, particularly in the southern U.S., suffered from infections
with parasitic hookworms. Many of these hookworms feed on blood cells of the host and thus
also consume iron that is found in red blood cells. A symptom of a heavy infection is a
craving to eat dirt—particularly clay-like soils with a high iron content. Thus, for these
people, iron is a __________.
a. tradeoff
b. constraint
c. part of the organism’s niche
d. nonlimiting resource
B
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In the figure above, which of the following survivorship curves implies that an animal may lay many eggs, of which a regular number die each year on a logarithmic scale?
A) curve A B) curve B C) curve C
In studying the medium ground finch on Daphne Major, the Grants noted that each generation of finches had beaks
A. best suited for their parents' environment. B. best suited for their current environment. C. smaller than those of the previous generation. D. larger than those of the previous generation.
A population of wolf spiders exemplifies a
____ population distribution. a. clumped b. random c. uniform d. constant e. homogeneous
Isolating mechanisms leading to speciation have been documented by ________
A) geographic isolation B) polyploidy C) temporal isolation D) a mutation in a single gene E) All of the above.