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Past Shows
January 24, 2009
 Download an MP3 of the entire program (22MB).
Fruitless Fall
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It's been a rough couple years for honeybees. Two years ago, hives across North America suddenly began to die out. One day they were fine, the next day they were empty of bees. Nearly two-thirds of North American honeybees have simply vanished. Researchers call it colony collapse disorder. The impact of the collapse goes far beyond not getting our daily fill of golden honey. About one third of our agriculture is dependent on bees for pollination. No bees -- no fruit, veggies or nuts. Rowan Jacobsen, a Vermont-based journalist, has been following the bee decline and he's written about it in his new book, Fruitless Fall: The Collapse of the Honey Bee and the Coming Agricultural Crisis. In his book, Mr. Jacobsen explores the origin of the collapse, its worrying consequences and what might be done to save the bees.
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Speedy Sperm
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An African cichlid, Copyright Dr. Jessica Drake, source Wikimedia
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Guys will do just about anything to make sure they find a good mate. And this is especially true in nature, where the signs of competitive mate selection are broadcast loud and clear: an impressive rack of antlers, a peacock's tail, an attractive mating call. But competitive mate selection can also drive some more subtle effects. Dr. Sigal Balshine, a behavioural ecologist at McMaster University, has been studying competitive mate selection in a family of African fish, called cichlids. She's found that male cichlids that must compete for access to a female, develop longer, strong and faster-swimming sperm than males that don't face as much competition.
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Mammoth Impact
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The think black layer of sediment in this cliff face included the tiny nanodiamonds. Courtesy University of Oregon
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About thirteen thousand years ago, something very bad happened in North America. Many species went extinct - mammoths, giant bears and sabretooth cats among them. The climate, which had been warming with the end of the last Ice Age, suddenly began to cool again. And the relatively recently arrived Clovis paleo-indians, who had been thriving on the empty continent, abruptly went into serious decline. The cause of all this has long been debated, but Dr. Doug Kennett, a professor of archeology at Oregon State University and his colleagues, have evidence that it might have been due to a cosmic impact. They have found tiny nanodiamonds in sediment that they think could only have been created by a medium-sized, but devastating, comet strike.
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Old Growth, New Death
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Stressed and dying fir trees in California - courtesy N. Stephenson, USGS
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The surviving old growth forests of western North America may be in trouble. A team of researchers, including Dr. Lori Daniels, a bio-geographer from the University of British Columbia, have found that the mortality rate for trees of all ages in old growth forests had doubled in the last couple of decades. The culprit, they think, is climate warming, which is leading to water stress in these trees. They think that this increased mortality will dramatically change these forests, which are thousands of years old. In the future, they'll be thinner, the trees will be younger, and the forests will be more vulnerable to disease, insects and mass die-offs.
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Science Fact or Science Fiction: Kids and sugar
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From time to time, we present a commonly held idea or popular saying - and ask a Canadian scientist to set us straight on whether we should believe it or not. And today’s statement is certainly something we've all heard before: Sugar makes kids hyperactive.
For the scientific lowdown, we go to Dr. Thomas Wolever, a professor in the Department of Nutritional Sciences at the University of Toronto. He tells us it's science fiction.
Theme music bed copyright Raphaël Gluckstein.
Creative Commons License by-nc-nd-2.0
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