Which term describes structures that have a reduced function but were functional in ancestors?

Which term describes structures that have a reduced function but were functional in ancestors?

• A. Vestigial structures
• B. Analogous structures
• C. Homologous structures
• D. Adaptive traits

Answer: (A)

Vestigial structures are remnants of features that were functional in ancestors but have reduced or lost their function in the present. They help show evolutionary history because they originate from parts that once served a purpose in related species. Examples include the human appendix, the coccyx, and whale pelvic bones—each traceable to past needs that no longer apply in the same way today. This concept is distinct from analogous structures, which look similar and perform similar tasks but arose independently, and from homologous structures, which share a common origin even if their current roles differ. Adaptive traits describe features that improve fitness in the current environment, not leftovers from ancestors.

Vestigial structures are remnants of features that were functional in ancestors but have reduced or lost their function in the present. They help show evolutionary history because they originate from parts that once served a purpose in related species. Examples include the human appendix, the coccyx, and whale pelvic bones—each traceable to past needs that no longer apply in the same way today. This concept is distinct from analogous structures, which look similar and perform similar tasks but arose independently, and from homologous structures, which share a common origin even if their current roles differ. Adaptive traits describe features that improve fitness in the current environment, not leftovers from ancestors.