In a species of salamander, there are two forms, red and yellow. As the yellow form becomes less common due to predation and the red form more common, the yellow form becomes less likely to be eaten and more likely to survive and reproduce. The yellow form then becomes more common and roles of red and yellow forms reverse. This maintains both forms in the population. This would be an example of
A. negative frequency-dependent selection.
B. directional selection.
C. disruptive selection.
D. balancing selection.
E. negative frequency-dependent selection and balancing selection are correct.
E. negative frequency-dependent selection and balancing selection are correct.
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Sexual selection affects male characteristics more than female characteristics. Sexual selection operates by which of the following methods?
A. Intrasexual selection, where one sex directly competes with each other for the opportunity to mate with the opposite sex. B. Intersexual selection, where females select mate on the bases of their physical attributes. C. intersexual selection, cryptic female choice. D. Intrasexual selection where one sex directly competes with each other for mates and intersexual selection where females select their mate because of physical attributes and through cryptic female choice. E. Predatory sexual selection, where females only choose mates that can avoid predators.
Individual plant cells typically gain or lose water mainly via ____
a. facilitated diffusion
b. symport c. guttation d. osmosis e. bulk flow
Which molecule is a six-carbon compound?
A. PEP B. PGAL C. Glucose-6-phosphate D. Pyruvate E. Phosphoglycerate (PGA)
As part of your research project, you travel to an island to learn more about the habitats and relationships of spiders, centipedes, and insects. You and your assistant plot out five different areas of the island and count the numbers of spiders, centipedes, and insects living in each plot. Your results show the following: Plot Insects Spiders Centipedes1300254242617103147152147397805791393The most plausible explanation for the high number of spiders in plot 4 is:
A. The flies and spiders worked together to eliminate the centipedes. B. There are no centipedes to prey on the spiders and there are abundant flies upon which to feed. C. There are too many flies overall. D. The spiders preyed on the centipedes and ignored the flies.