An earthquake decimates a ground-squirrel population, killing 98 percent of the squirrels The surviving population happens to ha
ve broader stripes on average, than the initial population. lE broadness of stripes is genetically determined, what effect has the ground-squirel population experienced during the earthquake?
A) directional selection
B) disruptive selection
C) a genetie bottleneck
D) gene flow
E) a founder event
Before the earthquake the gene pool of the parent population was bigger and carried different alleles for a lot of genes.
After the killing of 98% of the population, the surviving one has an incomplete representation of the original gene pool. We can think of this as a gene bottleneck; the new allele frequencies will be different that the parental population. IE: broadness of stripes has a higher frequency after the earthquake.
Answer: Where would the blood come from if there were a blockage just posterior to the middle cerebral artery on the left? If blood could not get to the middle cerebral artery through the posterior circulation, the blood would flow around the circle of Willis to reach that artery from an anterior vessel.
