Charles Darwin concluded that the 13 species of finches on the Galapagos Islands
A. Were identical to 13 species in northwestern South America
B. Probably evolved from one ancestral South American species
C. Had adapted to the same food source
D. All migrated to the island for temperate weather
The Correct Answer and Explanation is:
The correct answer is B. Probably evolved from one ancestral South American species.
Explanation:
Charles Darwin’s studies of finches on the Galápagos Islands played a pivotal role in the development of his theory of natural selection. When Darwin visited the islands in 1835, he observed 13 species of finches, each exhibiting unique characteristics, such as differences in beak size and shape. These finches were adapted to the specific environments and food sources available on the various islands. However, their similarities suggested a common origin, leading Darwin to hypothesize that they all likely evolved from a single species of finch that had migrated from the mainland of South America.
Darwin noted that the finches’ adaptations, particularly their beaks, were suited to different ecological niches. Some species had larger, stronger beaks for cracking hard seeds, while others had smaller, finer beaks suited for picking insects or feeding on flowers. This variation in beak structure seemed to be the result of natural selection, with each species adapting to the specific food sources available on their respective islands. Darwin’s observations led him to propose that these finches descended from a single ancestral species that arrived on the islands from South America, and over time, they evolved into distinct species due to different environmental pressures.
While the finches did indeed adapt to different food sources, Darwin did not conclude that they adapted to the same food source (as suggested by answer choice C). Moreover, Darwin did not claim that the finches were identical to species in northwestern South America (answer choice A) or that they migrated to the island solely for temperate weather (answer choice D). Instead, he recognized that geographic isolation, different food sources, and environmental pressures contributed to the speciation of these finches. This observation helped Darwin develop his theory of evolution by natural selection, which emphasized adaptation to local environments as a driving force in the formation of new species.