The similarity of the embryos of fish, frogs, birds, and humans is evidence of ______.

• A. artificial selection
• B. common ancestry
• C. convergent evolution
• D. genetic drift

Answer: (B)

Verified step by step guidance

1. Understand the concept of embryology: Embryology is the study of the development of embryos from fertilization to birth. Similarities in embryonic development across different species can provide evidence of evolutionary relationships.
2. Define common ancestry: Common ancestry refers to the idea that different species share a common ancestor if they exhibit similar traits, such as embryonic development patterns, due to inherited genetic information.
3. Eliminate incorrect options: Artificial selection refers to human-driven breeding for specific traits, which is unrelated to natural embryonic similarities. Convergent evolution describes unrelated species developing similar traits due to similar environmental pressures, not shared ancestry. Genetic drift involves random changes in allele frequencies in a population, which does not explain embryonic similarities.
4. Focus on the correct explanation: The similarity in the embryos of fish, frogs, birds, and humans suggests that these species share a common ancestor. This is because the genetic instructions for early development are conserved and inherited from a shared lineage.
5. Conclude: The correct answer is 'common ancestry,' as it best explains the observed embryonic similarities among these species.