Which of the following pairs of structures are considered homologous?

• A. The wing of a butterfly and the wing of a bird
• B. The fin of a shark and the flipper of a dolphin
• C. The eye of an octopus and the eye of a human
• D. The wing of a bat and the arm of a human

Answer: (D)

Verified step by step guidance

1. Understand the concept of homologous structures: Homologous structures are anatomical features in different species that share a common evolutionary origin, even if their functions differ. These structures arise from a shared ancestor and often have similar underlying anatomy.
2. Analyze the given options: Compare the anatomical features of each pair to determine if they share a common evolutionary origin. Homologous structures are not defined by their function but by their shared ancestry and structural similarity.
3. Focus on the correct answer: The wing of a bat and the arm of a human are homologous because both structures share a similar bone arrangement (humerus, radius, ulna, carpals, metacarpals, and phalanges) and originate from a common ancestor, even though their functions differ (flight vs. manipulation).
4. Contrast homologous structures with analogous structures: Analogous structures, like the wing of a butterfly and the wing of a bird, perform similar functions but do not share a common evolutionary origin. They arise due to convergent evolution rather than shared ancestry.
5. Conclude the analysis: Homologous structures provide evidence for evolutionary relationships and shared ancestry, which is a key concept in understanding the diversity of life on Earth.