Reference no: EM133280143

In years when abundant rain exists a biologist who studies plants on two remote islands separated from each other by over 500 miles notices that there are two variants of a single plant species (variant A and variant B) that both exist in similar proportions (50/50) on both islands. Both variants have thorns that discourage birds from eating their seeds, but the thorns of variant A plants are longer than those of variant B plants. The biologist returns every year to study the prevalence of these plants on both islands, and after 15 years of drought conditions on only one of the islands she notices that variant A now makes up 80% and variant B makes up only 20% of the total number of plants of that species on the island with the drought. What evolutionary principle is likely responsible for the observations regarding the prevalence of each variant after the prolonged drought? Develop a hypothesis to explain the observations discussed in this example.