Which type of structures indicates shared ancestry between species?

Which type of structures indicates shared ancestry between species?

• A. Analogous structures serve similar functions but evolved independently.
• B. Vestigial structures are reduced remnants that once had function.
• C. Homologous structures share a common ancestor and may have different functions.
• D. All organisms have the same structures.

Answer: (C)

Shared ancestry is revealed by homologous structures. These are body parts that share the same underlying anatomy because they come from a common ancestor, even if they are used for different functions today. For example, the forelimbs of humans, cats, whales, and bats all have the same basic bone arrangement (similar patterns of humerus, radius and ulna, carpals, metacarpals, and digits) despite being adapted for grasping, walking, swimming, or flying. This shows divergence from a common developmental plan over time. Analogous structures look similar because of function rather than shared ancestry, arising through convergent evolution. Vestigial structures are remnants of features that once had a function in ancestors but are reduced or unused now. The idea that all organisms have the same structures isn’t accurate.

Shared ancestry is revealed by homologous structures. These are body parts that share the same underlying anatomy because they come from a common ancestor, even if they are used for different functions today. For example, the forelimbs of humans, cats, whales, and bats all have the same basic bone arrangement (similar patterns of humerus, radius and ulna, carpals, metacarpals, and digits) despite being adapted for grasping, walking, swimming, or flying. This shows divergence from a common developmental plan over time.

Analogous structures look similar because of function rather than shared ancestry, arising through convergent evolution. Vestigial structures are remnants of features that once had a function in ancestors but are reduced or unused now. The idea that all organisms have the same structures isn’t accurate.