The transitional fossils of whales support the theory of evolution by natural selection by providing evidence of the gradual development of whales from land-dwelling mammals to fully aquatic creatures. For example, through studying fossils such as Pakicetus, Ambulocetus, and Basilosaurus, scientists have been able to observe the changes in the anatomical structure and behavior of animals that occurred during this evolutionary process. They have observed the gradual transformation of their limbs into flippers, the migration of their nostrils to the top of their heads to create blowholes, and the adaptation of their bodies for swimming and diving. These characteristics demonstrate how different anatomical features of whales evolved over time and helped them adapt to their changing environment. The existence of transitional fossils provides evidence of the evolution of species over long periods of time, thus supporting the theory of evolution by natural selection.
