Which methods provide important evolutionary insights?

• A. Observing weather patterns
• B. Analyzing only modern species' behavior
• C. Comparing genomes of a single population at one time
• D. Comparing fossils of different ages and locations, living populations under different selective pressures, and fossils to living populations

Answer: (D)

To understand how evolution occurs, you need evidence from both the present and the past, across multiple populations. Fossils give snapshots of organisms at different times and places, showing how traits appear and change over long periods. Comparing fossils with living species helps map out lineages and see when adaptations arose. Studying living populations that face different selective pressures shows how natural selection can shape traits in real environments, illustrating divergence and adaptation as it happens. Putting these lines of evidence together—fossil records, fossil-to-living comparisons, and variation among living populations under different pressures—provides the richest understanding of evolutionary processes. In contrast, weather patterns don’t reveal heritable changes; focusing only on modern behavior misses historical context; and examining just one population at one time lacks the temporal dimension needed to trace evolutionary history.