What term describes structures that share a common ancestry, such as the wing of a bird and the arm of a human?

• A. Analogous Structures
• B. Homologous Structures
• C. Vestigial Structures
• D. Adaptive Structures

Answer: (B)

The term that describes structures like the wing of a bird and the arm of a human is "homologous structures." Homologous structures are anatomical features that have a similar origin and development due to shared ancestry, even though they may serve different functions in different species. For example, the underlying bone structure in both the human arm and the bird wing reflects their common evolutionary heritage, with variations that adapt them to different environments and uses.

This concept highlights the idea of divergent evolution, where related species evolve different traits to adapt to their specific environments. In contrast, analogous structures arise from convergent evolution, where unrelated species develop similar traits independently, often due to similar environmental pressures, but do not share a common ancestral origin. Vestigial structures are remnants of features that were functional in ancestral species but have lost their original function. Adaptive structures refer to traits that have evolved over time to enhance survival and reproductive success in specific environments, but do not specifically indicate a shared ancestry.