Cheetahs are not a healthy species. Several million years ago they were widespread in Africa and Asia, but their numbers fell drastically during the last ice age and again when they were hunted to near extinction in the nineteenth century. Now, they
suffer from low survivorship (a large number of animals dying), poor sperm quality, and greater susceptibility to disease. Normally, an animal will reject tissue transplanted from another animal, but cheetahs will not reject tissue grafted on to them from another cheetah. What happened to the cheetah? How did their genetic variation change? Where does genetic variation ultimately come from? What mechanism can maintain and increase genetic variation in natural populations?
What will be an ideal response?
Cheetahs went through a bottleneck twice, once during the last ice age and again when they were hunted to near extinction. This caused a significant reduction in the genetic variation in their gene pool, and cheetahs now have very little genetic variation. With little genetic variation, the members of the species are all genetically very similar. Genetic variation ultimately comes from mutations, which produces new alleles. Genetic variation can be maintained and increased through gene flow.
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An advantage of sexual reproduction is to ____ among offspring.
A. produce new gene combinations B. reduce genetic diversity C. introduce new genes into a species D. None of the choices is correct.
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A) the continental United States B) the Pacific Ocean C) the Mississippi River D) Russia