The relative time of divergence from a common ancestor between two species can be estimated by which of the following methods?

• A. Comparing the number of molecular differences in homologous DNA or protein sequences
• B. Observing the physical similarities in adult morphology
• C. Counting the number of chromosomes in each species
• D. Measuring the rate of mitosis in somatic cells

Answer: (A)

Verified step by step guidance

1. Understand that estimating the relative time of divergence between two species involves comparing genetic or molecular data that accumulate changes over time.
2. Recognize that homologous DNA or protein sequences are sequences inherited from a common ancestor, and differences in these sequences can reflect the time since divergence.
3. Know that physical similarities in adult morphology can be influenced by environmental factors and convergent evolution, making them less reliable for precise divergence time estimation.
4. Realize that chromosome number alone does not provide information about the timing of divergence because species can have the same or different chromosome numbers regardless of their evolutionary distance.
5. Understand that the rate of mitosis in somatic cells is unrelated to evolutionary divergence and does not provide information about the time since two species shared a common ancestor.