Question

which of the following examples includes a genetic bottleneck?
overhunting of the american bison caused the population to decrease from millions to a few hundred by the late 1800s. conservation efforts brought the population back up, but there is little genetic diversity.
a mistake during dna replication causes the offspring of a yellow flowering plant to have blue flowers. the blue flower trait is passed on to successive generations.
some individuals in a population of bears have very thick coats that help them conserve heat and energy during cold winters. after several generations, the proportion of bears with thick coats increases.
some of the rare, red - winged finches from a small island fly to a nearby island to feed. they mate with the native brown - winged finches, which results in an increase in the red - wing allele frequency on the new island.

Explanation:

A genetic bottleneck occurs when a population is drastically reduced in size, leading to a loss of genetic diversity. In the case of the American bison, overhunting caused a severe population decline. Even though the population was later restored, the lack of genetic diversity indicates a genetic bottleneck. The other options do not involve a severe population reduction. The second option is a mutation, the third is natural selection, and the fourth is gene flow.

Answer:

Overhunting of the American bison caused the population to decrease from millions to a few hundred by the late 1800's. Conservation efforts brought the population back up, but there is little genetic diversity.