Final answer:
Relative dating is used to determine the sequence of geological events and the relative ages of fossils by examining their placement within rock layers, not their exact age in years.
Step-by-step explanation:
Using relative dating techniques to determine the geological ages of fossils so they can calculate the rate of speciation of early organisms implies comparing the placement of fossils within rock layers. Relative dating is a method used by geologists to infer which of two fossils is older or younger by examining their placement within the sedimentary layers. This is based on certain principles such as the law of superposition, which states that in undisturbed layers of sedimentary rocks, the oldest layers are at the bottom and the youngest are on top. Another key principle is the principle of lateral continuity, suggesting that layers are continuous and any interruption indicates a subsequent event. By applying these principles, scientists do not determine the exact age in years but can order events sequentially.