Exercise 5: What Makes Populations Evolve? ntists have long believed that the 14
ID: 193643 • Letter: E
Question
Exercise 5: What Makes Populations Evolve? ntists have long believed that the 14 species of finches on the Galápagos Islands evolved from a single species of finch that the islands one to five milion years ago. Recent research suggests that the original finches came from the Caribbean Islands. Different species live on different islands. For example, the medium ground finch and the cactus finch live on one island The large cactus finch occupies another island. Among the major differences in finch species are their beak sizes and shapes Evolutionary changes occur by many processes, one of which is natural selection Choose the answer that best reflects how an evolutionary biologist would answer the following questions with natural selection in mind What is the best way to characterize the evolutionary changes that occur in a finch population over time? Select one a. The environment causes specific mutations in individual finches to help them survive and reproduce b. Mutations occur to meet the changing needs of the finches )c. The proportions of finches with aifferent traits in a populaion change over t d The traits of each individual finch in a popúlation change over time 2) ere to searchExplanation / Answer
All species of Darwin's finches are closely related, having derived recently (in geological terms) from a common ancestor. They live in the largely undisturbed environment in which they evolved, and none has become extinct as a result of human activity. Consequently, whatever we can learn about their ecology and evolution gives us insights into the process of speciation under entirely natural conditions. An important factor in the case of evolution of finches, is that environmental change is an observable driving force in the origin of new species. When the first finches arrived on Galápagos, they may have encountered a climate and vegetation more like those of modern-day Cocos Island: warmer, wetter, and more humid conditions, fostering rain forest from the coast to the island peaks. Further environmental change has influenced the opportunities for speciation and diversification of finches throughout their history: The number of islands has increased, the climate has cooled, and the vegetation and food supply have changed.
Hence a) The environment causes specific mutations in individual finches to help them survive and reproduce