[Campbell Biology P.42] Which of the following best describes the principle of a "molecular... | Practice Question
Which of the following best describes the principle of a "molecular clock" as used in evolutionary biology?
A: It is a method used to estimate the absolute time of evolutionary change based on the observation that some genes evolve at constant rates.
B: It measures the rate of gene duplication within a genome over an organism's lifetime.
C: It is a metaphorical term for the predictable changes in species due to natural selection over long periods.
D: It is a tool used to determine the exact geological age of fossils by analyzing radioactive decay.
Explanation
A molecular clock is a technique used in molecular evolution to estimate the time when two species diverged from a common ancestor. It relies on the assumption that mutations accumulate in DNA sequences at a relatively constant rate over time.