Global warming is causing more and more ice to melt each year at far-northern latitudes, exposing more bare ground than ever before. These vast areas of brown ground coloration make polar bears (which are white) much more conspicuous to their prey. Recently, an infant polar bear was born with brown fur. This polar bear survived to adulthood and has sired several offspring with brown fur. Which of the following is a plausible explanation of how the brown fur trait appeared in these polar bears? (a) A polar bear realized it would be better to be brown in order to hide more effectively. It induced mutations to occur in its fur pigment gene, which resulted in a change in pigment from white to brown fur. (b) One or more random mutations occurred in the fur pigment gene in an individual polar bear embryo, which resulted in a change in pigment from white to brown fur. (c) Increased temperatures due to global warming caused targeted mutations in the fur pigment gene in an individual polar bear embryo, which resulted in a change in pigment from white to brown fur. (d) A female polar bear realized it would be better for her offspring to be brown and therefore mated with a grizzly bear to achieve this result.

Global warming is causing more and more ice to melt each year at far-northern latitudes, exposing more bare ground than ever before. These vast areas of brown ground coloration make polar bears (which are white) much more conspicuous to their prey. Recently, an infant polar bear was born with brown fur. This polar bear survived to adulthood and has sired several offspring with brown fur. Which of the following is a plausible explanation of how the brown fur trait appeared in these polar bears? (a) A polar bear realized it would be better to be brown in order to hide more effectively. It induced mutations to occur in its fur pigment gene, which resulted in a change in pigment from white to brown fur. (b) One or more random mutations occurred in the fur pigment gene in an individual polar bear embryo, which resulted in a change in pigment from white to brown fur. (c) Increased temperatures due to global warming caused targeted mutations in the fur pigment gene in an individual polar bear embryo, which resulted in a change in pigment from white to brown fur. (d) A female polar bear realized it would be better for her offspring to be brown and therefore mated with a grizzly bear to achieve this result.