Whales

Michael Haggard
Zoology 4th Hour
August 21st, 2011


	The journal on the evolutionary of whales, more specifically their close relationship to the hippopotamus, was written by David Kerk. He is a professor of Biology at Point Loma Nazarene University. He obtained his PhD in Anatomy at UCLA, and currently lives on Vancouver Island, in Parksville, B.C. Canada. He is also involved in bioinformatics research at the University of Calgary.
	He used previously known information about whales having at least traces of unused bones to hypothesis about the evolutionary relatives of the whale.  Whales have forelimbs which have evolved into flippers, but they do not have hind limbs for the most part. This causes a general problem that can be solved by the use of fossil records, and how the whales evolved from even-toed hoofed mammals. Whales do have a specific modification in their skull for underwater hearing. Using this in combination with fossil records, Kerk traced back to an extinct whale ancestor known as Pakicetus. Noticing the similarities between more recent relatives of the whale, and tracing backwards how the modifications evolved to adapt to water, he was able to conclude that whales were indeed evolved from hoofed animals. However, he still needed to trace the whale’s closest modern relative, the hippopotamus, to these ancestors. Looking at fossil records, the hippopotamus shared characteristics of whale ancestors, and “cousin” ancestors, in the fact that their skeleton is specially thickened. This means that hippos (and extinct Indonhyus, “cousin” ancestor to the whale) are good “bottom-walkers” as the thick skeleton prevents them from floating. It is also shown in whales, making them have neutral buoyancy. Thus, from his testing, he concluded that although there isn’t enough evidence to consider the case closed, it is most likely true from the knowledge we have now, that hippos are the closest relatives to whales.
	I would place this on a high-school reading level, but it could be useful to anyone interested in this subject.  Anyone that needs information on the evolutionary family of whales, or phylogenetic traits of whales and their ancestors could use this journal.  I learned that hippopotamus’s are most likely related to whales, and that whales are actually evolved from hoofed mammals similar to horses.