The Galápagos finches are an example of an array of species that:

• A. are genetically identical but show different behaviors
• B. arose independently on each island through convergent evolution
• C. were introduced to the islands by human activity
• D. evolved from a common ancestor through adaptive radiation

Answer: (D)

Verified step by step guidance

1. Understand the concept of adaptive radiation: Adaptive radiation refers to the process by which organisms diversify rapidly into a variety of forms to adapt to different environmental niches. This often occurs when a single ancestral species colonizes a new area with diverse habitats.
2. Recognize the role of the common ancestor: The Galápagos finches evolved from a single ancestral species that arrived on the islands. This ancestor gave rise to multiple species, each adapted to specific ecological niches on the islands.
3. Identify the environmental factors: Different islands in the Galápagos have unique environments, such as variations in food availability (e.g., seeds, insects). These environmental pressures led to the evolution of distinct beak shapes and feeding behaviors in finches.
4. Clarify why other options are incorrect: The finches are not genetically identical; they have distinct genetic differences corresponding to their adaptations. They did not arise independently through convergent evolution, as they share a common ancestor. Additionally, they were not introduced by humans but naturally colonized the islands.
5. Conclude with the correct explanation: The Galápagos finches are an example of species that evolved from a common ancestor through adaptive radiation, driven by natural selection and environmental pressures on the islands.