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Past Shows
January 6, 2007
 Download an MP3 of the entire program (22MB) (available Saturday, two hours after broadcast).
Ailing Ayles Ice Shelf
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Satellite image showing the Ayles Ice Shelf on August 13, 2005, as it breaks off Ellesmere Island - Courtesy, NASA |
During the unseasonalby warm summer of 2005, the Ayles Ice Shelf broke off the northern shore of Ellesmere Island. No one was there to witness it, but scientists noticed the event a couple days later during a routine check of radar images. Dr. Luke Copland, a glaciologist at the University of Ottawa, has spent over a year reconstructing exactly what happened. Dr. Copland says that the unseasonable temperatures contributed to a reduction of the sea ice that normally protects ice shelves from the wear and tear of wind and waves. The year 2005 was also particularly windy and Dr. Copland surmises that without the sea ice to protect it, rough waters went to work on Ayles. Surprisingly, the event occured in just under an hour. Ayles, which is now an ice island, is about the size of Manhattan Island and is making its way through the Arctic ocean. Dr. Copland says it will eventually find its way to the North Atlantic where it will melt. But scientists are concerned that it might be another sign of global climate change.
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Titan: Land O' Lakes
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A colorized radar image of Titan's methane/ethane lakes - Courtesy, NASA/JPL/USGS |
Last July, NASA's Cassini probe swung around the northern hemisphere of Jupiter's second largest moon, Titan. Dr. Ellen Stofan, who analyses the radar images beamed back from Cassini, was exhilarated when she first saw the flyby images. It turns out that Titan's high northern regions are dotted with lakes remarkably similar to those on Earth, with one big difference: they're a mix of liquid methane and ethane. The lakes range in size from three to 70 kilometres across. Dr. Stofan believes they form from Titan's methane rain and through an underground methane table or "methanofer." The lakes are the ultimate natural chemistry lab, says Dr. Stofan. They offer scientists a tantalizing glimpse at a frozen version of the primordial soup from which life was thought to originate on Earth. Dr. Stofan is a research scientist with Proxemy Research in Washington, DC.
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Evolution: What Will Become of Us?
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A 19th Century caricature of Charles Darwin |
We are only the latest of the human species to have walked the earth, and as we understand evolution better, we may be able to predict what the next stage in human evolution will be.
Dr. Steve Jones, a professor of a genetics at University College, London, and President of the Galton Institute, points out that, to a large extent, we have neutralized the effects of evolution by natural selection. Technology, medicine and public health have reduced the impacts of predators, the environment and disease which have been so influential in our past evolution.
Dr. Noel Boaz, author of several books on human evolution including Evolving Health, and a physical anthropologist and professor of anatomy at Ross University of Medicine, suggests evolution will continue despite the weakness of natural selection. Our environment will still have an influence on our evolution, even if our environment is not a natural one. In particular the diseases of modern life and urban environments, like obesity and pollution, may determine the shape of humans of the future.
In the absence of any kind of selection, however, we will still evolve according to Dr. Katherine Pollard, a professor at the Genome Center and the Department of Statistics at the University of California, Davis. The theory of Neutral Drift predicts that we will continue to change through future evolutionary time, but in unpredictable and essentially random ways.
A much faster version of evolution having little to do with natural biological mechanisms may be in our future according to Joel Garreau, author of Radical Evolution and writer and editor with the Washington Post. We may transform ourselves using things like nanotechnology and genetic engineering and completely take control of our own evolution.
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Question of the Week: Menstruation in Mammals
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This week, Louise Kane from Ottawa sent us this question: Are humans the only species that undergo menstruation?
For the answer, we turn to Dr. Katherine Wynne-Edwards, an evolutionary endocrinologist from the Department of Biology at Queen's University.
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