Dr. Hans Thewissen Presents Lecture at Mount Union College
April 06, 2010
Dr. Hans Thewissen, associate professor of anatomy at the Northeastern Ohio Universities Colleges of Medicine and Pharmacy (NEOUCOM), spoke at Mount Union College on Monday, February 26 discussing the evolution of whales.
Much of Thewissen's research has concentrated on the land to water transition of whales, dealing especially with organ system adaptations. Thewissen has been traveling to India since 1992 and to Pakistan since 1984 where he has excavated fossils of early whales, sea cows, crocodiles, sharks and primates.
He opened his discussion using examples from Moby Dick (1851) and Origin of Species by Darwin (1859) on the evolution of whales. Whales first originated 50 million years ago in South Asia, evolving through five stages. Thewissen's team has discovered three of the five stages from the past 10 million years.
Thewissen split up his presentation into six parts, opening with fieldwork his team and he have done in Pakistan and western India discovering remains of the whales. 'They have a great fossil record,' said Thewissen.
He then discussed the evolution of whales in four 'acts,' on whales learning to swim, their loss of land locomotion, their development and what it teaches us today about evolution.
Thewissen said the four 'acts' started to classify whales 50 million years ago when whales were land-freshwater mammals living in shallow channels, called 'Pakicetidae.' During act II, called 'Ambulocetus,' 49 million years ago, whales were bigger, longer and lived in swampy areas in Pakistan. Remingtonocetid, 43-46 million years ago, were found in coastal swamps in India. 'They had an elongated, mouths, flat tails, and could be found in an area much like the Outer Banks in North Carolina,' said Thewissen. During act IV, called 'Dorudontidae and Basil Osauraidae,' was 40 million years ago and considered whales as near shore marine mammals.
Thewissen then discussed and explained the loss of hind limbs the whales have experienced over time, evolving into the mammals they are today. He uses a process called 'Immunochemistry' to determine the genes that are responsible for the hind limbs.
A faculty member at NEOUCOM since 1993, he earned bachelor and master of science degrees from the University of Utrecht in the Netherlands and a doctoral degree from the University of Michigan. His research interests include the evolution of whales, the evolution of flight in bats, evolution of primates and patterns of bone formation in the human skull.
Thewissen's presentation was sponsored by Beta Beta Beta, Mount Union's biology honorary.