Martin Wikelski and L

question 51

Multiple Choice

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.
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Examine the figure. What type of selection for body size appears to be occurring in these marine iguanas?

• A) directional selection
• B) stabilising selection
• C) disruptive selection
• D) You cannot determine the type of selection from the above information.

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