Why are molecular clocks important in the construction of cladograms?

• A. They help determine the metabolic rates of different species.
• B. They are used to identify the geographic locations where species evolved.
• C. They estimate the timing of evolutionary divergences by comparing genetic differences.
• D. They directly measure the physical traits of organisms to determine relatedness.

Answer: (C)

Verified step by step guidance

1. Understand the concept of molecular clocks: Molecular clocks are tools used in evolutionary biology to estimate the timing of evolutionary events. They rely on the assumption that genetic mutations accumulate at a relatively constant rate over time.
2. Recognize the role of genetic differences: Molecular clocks compare genetic differences between species to infer the time since their last common ancestor. This is based on the principle that more genetic differences indicate a longer time since divergence.
3. Connect molecular clocks to cladograms: Cladograms are diagrams that show evolutionary relationships among species. Molecular clocks provide a timeline for these relationships, helping to place divergence events in chronological order.
4. Clarify why molecular clocks do not measure physical traits or metabolic rates: Physical traits and metabolic rates are influenced by environmental factors and do not provide a consistent measure of evolutionary time. Molecular clocks focus on genetic data, which is more reliable for estimating divergence times.
5. Explain why molecular clocks are not used to identify geographic locations: Geographic locations are determined through fossil evidence and other historical data, not molecular clocks. Molecular clocks are specifically used for timing evolutionary divergences based on genetic differences.