Which statement best describes studying fossil sticklebacks for evolutionary research?

• A. Fossils allow direct DNA analysis
• B. Fossils provide no information about evolutionary rates
• C. Fossils can only show superficial morphology
• D. Studying fossils enables analysis of evolutionary rates across geologic time scales

Answer: (D)

Fossil data provide a time-stamped record of how traits change, so researchers can quantify how fast evolution occurs over long periods. When we examine fossil sticklebacks from different geologic layers, we can compare their morphology across known time intervals and calculate rates of change per unit time. This long-term perspective is exactly what lets scientists study evolutionary rates across geologic time scales.

Direct DNA analysis from fossils is not generally possible for most fossil records, especially across deep time, which is why the statement about obtaining DNA from fossils isn’t reliable. Fossils also reveal more than just superficial features; preserved skeletal and other morphological details can show meaningful evolutionary differences that inform rate calculations.