Which type of reproductive isolation most likely played a key role in the speciation of Galápagos finches?

• A. Temporal isolation, such as breeding at different times of year
• B. Gametic isolation, where sperm and egg cannot fuse
• C. Mechanical isolation, such as incompatible reproductive organs
• D. Behavioral isolation, such as differences in mating songs

Answer: (D)

Verified step by step guidance

1. Understand the concept of reproductive isolation: Reproductive isolation refers to mechanisms that prevent different species or populations from interbreeding and producing viable offspring. It is a key factor in the process of speciation, where new species arise.
2. Review the types of reproductive isolation: Temporal isolation occurs when species breed at different times, gametic isolation happens when sperm and egg cannot fuse, mechanical isolation involves physical incompatibilities in reproductive organs, and behavioral isolation involves differences in behaviors, such as mating calls or rituals, that prevent interbreeding.
3. Analyze the context of the Galápagos finches: The finches are known for their diverse adaptations, including differences in beak size and shape, as well as unique mating songs. These differences in mating songs are a form of behavioral isolation.
4. Connect behavioral isolation to speciation: Behavioral isolation prevents interbreeding between populations with different mating songs, leading to reduced gene flow. Over time, this can result in the formation of distinct species.
5. Conclude that behavioral isolation is the most likely mechanism: Based on the information provided, differences in mating songs among Galápagos finches played a key role in their speciation, making behavioral isolation the correct answer.