Final answer:
Fossils are crucial in providing evidence for the divergence of species from a common ancestor by showing the progression of evolutionary changes over time in the fossil record, including morphological differences and the ability to hybridize.
Step-by-step explanation:
Fossils provide evidence for the divergence of two species from a common ancestor by showcasing gradual evolutionary changes. When scientists find fossils of an ancestral species, they can observe the traits that persist, diverge, or adapt in species over time through the fossil record. If divergent evolution has occurred, the record will illustrate how each species has developed unique characteristics from a shared ancestor, despite starting from a similar genetic blueprint. Fossils may also show that over time, two species that have diverged maintain the ability to hybridize, which indicates that they are closely related. This evidence is seen in the morphological similarities and differences among the fossils, the determination of their ages, and their geographic distribution, which tells the tale of their evolutionary paths.