Which statement best distinguishes homologous traits from analogous traits?

Which statement best distinguishes homologous traits from analogous traits?

• A. Homologous traits arise from independent evolution with similar function.
• B. Homologous traits are present in a common ancestor, while analogous traits arise independently in separate lineages with similar function.
• C. Analogous traits are inherited from a common ancestor.
• D. Homologous traits occur only in fossils.

Answer: (B)

A key idea is ancestry paired with shared structure. Homologous traits come from a common ancestor and often keep a similar internal pattern (like bone structure) even if their functions differ today. That shared origin shows up in the forelimbs of humans, cats, whales, and bats—each uses the same basic set of bones, but they’ve adapted to very different lives. Analogous traits, on the other hand, arise when different lineages face similar environmental challenges and independently evolve similar functions. Their underlying structures aren’t from a recent common ancestor. Wings of birds and insects both let you fly, but their anatomy is different because they evolved separately. So the best distinction is that homologous traits reflect inheritance from a common ancestor, while analogous traits arise independently in separate lineages with similar function.

A key idea is ancestry paired with shared structure. Homologous traits come from a common ancestor and often keep a similar internal pattern (like bone structure) even if their functions differ today. That shared origin shows up in the forelimbs of humans, cats, whales, and bats—each uses the same basic set of bones, but they’ve adapted to very different lives.

Analogous traits, on the other hand, arise when different lineages face similar environmental challenges and independently evolve similar functions. Their underlying structures aren’t from a recent common ancestor. Wings of birds and insects both let you fly, but their anatomy is different because they evolved separately.

So the best distinction is that homologous traits reflect inheritance from a common ancestor, while analogous traits arise independently in separate lineages with similar function.