Mason Voorhees Period 1
Summary:

The first form ever of a whale was a Indohyus. An Indohyus is a animal from land which evolved into a Pakicetus. A Pakicetus lived in an aquatic habitat (close by water). The animal developed a thick bone wall around the ears. A Pakicetus evolved in to an Ambulocetus. An Ambulocetus developed a large powerful tail, their legs got shorter, and a fat pad which turned the Ambulocetus into a Kutchicetus. The Kutchicetus had some selective pressure and had to adapt to a salt water habitat instead of a fresh water habitat. The Kutchicetus turned into an animal that looks like a dolphin called “Odontocetes”. An Odontocetes developed Echolocation for hunting other animals under water. Then it developed into a whale (Mysticetes) and developed Baleen for filtering food. Its eyes also became vestigial organs because there were no longer used since it use echolocation.

Analysis:

This article was great because it really told me how the whale evolved. In this article I learned all the forms there were before the whale was created and when certain characteristics were added. This article relates to me because I was wondering what a whale was before it was a whale and I was wondering why they were so big. In class we are learning about evolution. This relates to our topic at school because it is about how the whale evolved. This article was interesting because I didnt know whales had legs or hips until I read about. I also didnt know whales were land creatures. I am still wondering why whales wanted to go back in the water even though they were in the water before they evolved into land animals.

Work Cited
Brown, D. (1994, ). A whale of a discovery. Washington Post National Weekly Edition Retrieved from http://sks.sirs.swb.orc.scoolaid.net

A WHALE OF A DISCOVERY by David Brown
Washington Post Staff Writer

A footed ancestor to the marine mammals probably walked as well as swam

What did a 650-pound, 50-million-year-old whale do on land? The answer probably wasn't "Anything it wanted!" More likely, it was humping around clumsily like a sea lion, perhaps mating, birthing or suckling, but almost certainly looking forward to its next dip in the water.

"Of course, we can't be sure that's what this critter did, but that's one thought," J.G.M. Thewissen, a comparative anatomist, says about his recent discovery of what is thought to be a new genus and species: Ambulocetus natans, the walking whale that swims.

The fossil find may help solve a longstanding riddle of evolution: How and when did whales--whose ancestors were four- footed, land-dwelling mammals--develop the ability to live in the ocean?

Evolutionary biologists have believed for a long time that marine mammals are the product of a trip back into the primordial sea, not an incomplete escape from it. Little is known, however, about animals that occupied the evolutionary midpoints between the completely terrestrial whale-ancestors and the completely aquatic whales.

Ambulocetus natans is one of those transitional species--not exactly the "missing link" but a link in the missing chain.

Thewissen, who teaches anatomy at Northeastern Ohio Universities College of Medicine, discovered the remains of the ancient whale in northern Pakistan in January 1992 during an expedition sponsored, in part, by the National Geographic Society. He was accompanied by S.T. Hussain, an anatomy professor at Howard University College of Medicine, and M. Arif of the Geological Survey of Pakistan. The team was originally looking for fossils of land animals.

The site is where the crustal plate containing present-day India, Pakistan and Bangladesh meets the one containing central Asia. The collision of the two long ago obliterated an ancient body of water called the Tethys Sea. Before that, however, "land bridges" would have formed between the plates, allowing migration of animals and making