Martin Wikelski and L. Michael Romero (Body size, performance and fitness in Galápagos marine iguanas, Integrative and Comparative Biology 43 [2003]:376-86) measured the snout-to-vent (anus) length of Galápagos marine iguanas and observed the percent survival of different-sized animals, all of the same age. The graph shows the log snout-vent length (SVL, a measure of overall body size) plotted against the percent survival of these different size classes for males and females. Currently the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferably catch and eat slower iguanas are introduced to the island,
iguana body size is likely to _____ in the absence of other factors; the iguanas would then be under _____ selection.
A. increase; disruptive
B. decrease; disruptive
C. stay the same; stabilizing
D. decrease; directional
E. increase; directional
Ans: D. decrease; directional
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Taste cells that respond to sour specifically interact with ____
a. sodium ions b. hydrogen ions c. quinine d. sugars e. glutamate
Why is fat the body's preferred way of storing energy?
What will be an ideal response?
Zebra mussels were introduced into Lake St. Clair around 1988
The table lists the population densities (in grams dry weight per square meter of lake bottom) of native unionid mussels and exotic zebra mussels in the lake before and after this introduction. Both groups feed by filtering small particles from the water. Based on the information given, which of the following best describes the likely relationship between zebra mussels and unionids? Year Unionids Zebra mussels 1986 4.5 0.0 1990 3.7 4.6 1992 1.3 3.4 1994 0.1 3.2 A) Zebra mussels and unionids have no effect on each other. B) Zebra mussels exert a density-independent control on unionid populations. C) Zebra mussels exert a density-dependent control on unionid populations. D) Unionids exert a density-dependent control on zebra mussel populations. E) Unionids exert a density-independent control on zebra mussel populations.
Molecules that facilitate the work of enzymes by binding with them are ________
Fill in the blank(s) with correct word