Question

Which of the following is an example of homologous structures that provide evidence for evolution?

• A. Wings of a bird and wings of an insect
• B. Forelimbs of a human and wings of a bat
• C. Fins of a fish and flippers of a whale
• D. Stingers of a bee and spines of a porcupine

Hint:

Distinguish homologous structures (same origin, different functions) from analogous structures (different origins, similar functions). Homologous structures, like vertebrate forelimbs, support common ancestry.

Answer 1

The Correct Option is B

Homologous structures, found in different species, originate from a common ancestor and exhibit similar anatomical foundations, though divergent evolution may lead to disparate functional roles. For example, human forelimbs and bat wings are homologous. Their shared skeletal framework (humerus, radius, ulna, digits) signifies derivation from a common tetrapod ancestor. Despite this shared origin, human forelimbs are adapted for manipulation, while bat wings are adapted for flight.
The other comparisons are not of homologous structures:
- Bird wings and insect wings are analogous; they perform the same function (flight) but have distinct anatomical origins (feathers versus chitinous structures).
- Fish fins and whale flippers are analogous; they facilitate similar functions (swimming) but develop from different embryonic tissues (mesoderm in fish fins, tetrapod limb buds in whale flippers).
- Bee stingers and porcupine spines are not homologous, possessing different origins and functions (modified ovipositors in bees, modified hairs in porcupines).
Therefore, the homology between human forelimbs and bat wings serves as evidence for evolutionary relationships.