This article talks about the evolution of whales, and other underwater sea creatures that need to be explored as well. In his studies, Gingerich discovered pakicetus, a terrestrial mammal dating from 50 million years ago, whose ear bone resembles a whale, and has a skull that pictures a dog. After searching for bones in Pakistan, Gingerich found a new anklebone from a whale that strongly resembled the one of a artiodactyl. After this discovery he saw how closely related the whale is to antelopes. This discovery showed America that his studies of evolution were true, and that Darwin's theory was correct.
Philip D. Gingerlich was a paleontologist who is famous for his work on the ancestory of whales. His work was mainly on fossils from Egypt and Pakistan. He discovedrd Pakicetus, Ambulocetus, and Rodhocetus balochistanensis.
1.PAKICETUS: "Gingerich & Russell (1981) correctly identified new material recovered from the Kuldana Formation outside of Punjab, Pakistan, as the most primitive known whale, and appropriately, named it Pakicetus. This specimen is an exquisite transitional form documenting the derivation of whales from terrestrial animals, such as mesonychids. The skull of Pakicetus was all that was known until 2001, but much of the dentition and braincase were preserved and displayed the mixture of apomorphic and plesiomorphic characters within this taxon." (http://wiki.cotch.net/index.php/Pakicetus)
2.AMBULOCETUS: "Ambulocetus ("walking whale") was an early cetacean that could walk as well as swim. It lived during early Eocene some 50-49 milion years ago. It is a transitional fossil that shows how whales evolved from land-living mammals. Having the appearance of a 3 metre long mammalian crocodile, it was clearly amphibious, as its back legs are better adapted for swimming than for walking on land, and it probably swam by undulating its back vertically, as otters and whales do." (http://en.wikipedia.org/wiki/Ambulocetus)
3.RODHOCETUS BALOCHISTANENSIS: "Rodhocetus is one of several extinct whale genera that possess land mammal characteristics, thus demonstrating the transition from land to sea that whales went through." (http://en.wikipedia.org/wiki/Rodhocetus)
Ginerich's foundations were good and shocking but he thought just a little more evidence would confirm his discovory. The match to those Eocene carnivores might be close, but not close enough. The solution to this problem was DNA hybridization, which suggested that whales had descended from artiodactyls or in other words even-toed herbivours, such as antelopes. So later on in Pakistan his group found a single piece of fossil that changed the already existing view in paleontology. It was a half of a pulley-shaped anklebone, known as astragalus, belonging to another new species of whale. The his coleague found the fragment's of the other half. When Gingerich fitted them together he had an anklebone from a four legged whale dating back 47 million years. Suddenly he realized how closely related whales are to antelopes.
http://www.botany.wisc.edu/courses/botany_400/Lecture/0pdf/31MolSyst.pdf
http://www-personal.umich.edu/~gingeric/PDGwhales/Whales.htm
http://www.nationalgeographic.com/magazine/0411
"Skeletal remains of Eocene Archaeoceti provide the only direct and unequivocal evidence of the evolutionary transition of whales from land to sea. Archaeocete skeletons complete enough to be informative about locomotion are rare (principally Rodhocetus and Dorudon), and these deserve to be studied in comparison to the full spectrum of semiaquatic mammals. A principal components analysis of 14 trunk and limb measurements for 50 species of living semiaquatic mammals reduces the observed variation to three informative axes." (http://cat.inist.fr/?aModele=afficheN&cpsidt=15021723)
Discovering the origins of the modern day whale has been the passion of Philip D. Gingerich. In order to prove his theories that the whale had been a land mammal, he has collected fossil specimens of what are thought to be early whales. He, as well as some of his colleagues, discovered many specimens such as Pakicetus, Ambulocetus natans and Rodhocetus balochistanensis. These ancestors of the whale help Gingerich and other scientists help prove the origin of our modern day whale. “However, evolutionary biology predicts more than just the existence of fossil ancestors with certain characteristics - it also predicts that all other biological disciplines should also reveals patterns of similarity among whales, their ancestors, and other mammals correlated with evolutionary relatedness between groups” (http://www.talkorigins.org/features/whales/). In short, these fossils can be used in many more ways to find the whales ancestors. The characteristics of the whale and these fossils will tell us the whale’s origins. To further discover the whales movement from land to water, scientists will need more evidence to convince skeptics.
