Natural and artificial selection — practice question

Scientists examined how strongly the founder effect and natural selection influenced evolutionary change. Fig. 5.1 shows the brown anole lizard, $Anolis\ sagrei$. These lizards occur on several Caribbean islands and eat many kinds of invertebrates and other small animals. $A.\ sagrei$ spends much of its time perched (resting) on, or travelling along, branches of shrubs and trees. The width of the branch on which $A.\ sagrei$ perches is called the perch diameter. There is a positive correlation between perch diameter and hind limb length of $A.\ sagrei$. In 2004, a hurricane killed all the $A.\ sagrei$ lizards on seven islands. In 2005, researchers randomly took seven male and seven female lizards from a source population on a nearby island and founded new populations on each island. Fig. 5.2 shows the variation in vegetation between the source island and the seven experimental founder islands.