Based on the topic of the research, the anatomical structure that will be discussed is the pelvic bone of the modern whale, and the evidence of evolution that exists in the structure that lost its vestige. According to an online article by Brian Switek for the “Smithsonian”, an estimated 375 million years ago (mya) vertebrates that had arms and legs, known as the first tetrapods, made their out from one ecosystem (swamp) to another (terrestrial), to roam about. Dinosaurs remained the superior invertebrates during the time (Eocene period), the first group of mammals had evolved an estimated 200mya; during this interval, they became diverse, but small in size until terrestrial dinosaurs became extinct 65mya. Due to this incident, the major radiation (derived from the term, “Evolutionary Radiation”, is defined as the increase of diverse species from an ancestral species into different forms) occurred, which led to the first whales to evolve from the tetrapods that made their way out of the swamp ecosystem. Whales (Early cetaceans) are known to being one-of-the-best documented examples of an evolutionary change of such a large scale due to their fossil track record for the fossils found which …show more content…
The discovery of an early ancestor of the whale, the Pakicetus inachus, from 500mya shows the transition between animals on land and in water. Based on the fossil found, the anatomy of the species showed it was mobile on land, but with features that suited life in the sea. The fossils found in the year 1994, similar to the Pakicetus inachus, showed strong characteristics to whales than other mammals (cetaceans.) According to Philip Gingerich (Gingerich) and Donald Russell (Russell), both who discovered the fossil in Pakistan, 1994, validated the proof that the transition of the whale from land to sea exists as a fossil and proof of