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Snakes in the 'Glades
Burmese python in the Everglades (Wikimedia Commons) |
The Burmese python is native to Southern and Southeast Asia. It is a
constrictor and one of the largest snakes in the world. Burmese pythons became popular
pets in the United States decades ago. Since then, their release into the wild has
created a huge ecological problem throughout Florida's Everglades National
Park. In the rich Everglades the pythons bred like rabbits, and ate like
wolves. A new study by Dr. Michael Dorcas from the Department of Biology at
Davidson College in North Carolina has revealed the extent of that problem for
the first time. The pythons' prey, mid-sized mammals and birds, seem to be
crashing catastrophically. The raccoon population has decreased by 99%, opossums
by 98% and the bobcat population is down 87%. Rabbits and foxes have
effectively disappeared. Several of the birds being preyed on by the python are
already on the endangered list, and their fate is unknown. The overall
ecological health of the Everglades is threatened because at present there is no
way of controlling the Burmese python population.
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Launching the Little Ice Age
(University of Colorado Boulder) |
The Little Ice Age put Europe in a deep freeze for hundreds of years, up
until the early 19th century. However, researchers have never agreed on the
cause and the exact time of onset for this long cooling trend in the Northern
Hemisphere. New research by Dr. Gifford Miller, a professor of geological sciences at the University of Colorado, Boulder, and the Institute of Arctic and
Alpine Research, and his colleagues, may have solved the puzzle. They have
dated recently exposed frozen plants from under retreating ice caps on Baffin
Island. Those plants turn out to have been frozen in just as the Little Ice Age was
starting. The abruptness of the cooling that froze them led to a scenario in
which multiple volcanic eruptions at the end of the thirteenth century cooled
the north, and triggered a feedback loop that kept things cold for half a millennium.
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Super-sizing Mammals
LIfe-sized model of Indricotherium, a horneless rhino that was the largest land mammal that ever lived (WolfmanSF/Wikimedia Commons) |
During the Age of Dinosaurs, all mammals were small. But after the
dinosaurs died out, some mammals -- including certain lineages of elephants,
rhinos and whales -- grew to gargantuan proportions. An international team of
scientists, including Dr. Jessica Theodor of the University of
Calgary, recently compiled a database of the largest mammals through the ages to
learn how these size changes evolved. They found that on average, it took at
least 24 million generations for a land mammal to go from mouse-sized to
elephant-sized, but the same size change took just half that number of
generations for marine mammals such as whales. The researchers also found
that mammals can go from super-sized to small again 10 times as fast as they
grew, as in the case of some island-dwelling dwarf mammoths and elephants. Dr.
Theodor provided some insights into the reasons for these trends and explained
why size matters.
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Arrival of the Arctic Killers
Inuit hunters like these help scientists with 'traditional ecological knowledge.' (Wkimedia Commons) |
The declines in seasonal Arctic sea ice has opened northern waters to killer whales or orcas, who have recently increased their range into areas
where they were previously rare or unknown. However, the hunting and dietary
habits of orcas in the north are not well understood, so estimating the impact
on other wildlife of this fearsome predator has been a challenge. Dr. Steven
Ferguson, a marine biologist from the Department of Fisheries and Oceans and
the University of Manitoba, enlisted the help of over 100 Inuit hunters and
elders, whose knowledge of arctic ecosystems has been honed by generations of
life on the land, sea and ice, to help fill in the picture of killer whale
behaviour in the North. The Inuit described killer whales eating ringed, harp,
bearded and hooded seals, as well as other whales, including narwhal, bowhead
and beluga. It is hoped that this combination of scientific knowledge and
traditional observation can be a powerful tool in understanding changes in the
Arctic.
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Levitating Flies
Fruit flies can be levitated right off the floor of their container and kept weightless for weeks, right here on Earth. In a recent study, Dr. Richard Hill of the University of Nottingham and his colleagues used a superconducting magnet and a technique called diamagnetic levitation to create a controlled, weightless environment on Earth. They say the levitated flies behaved just like a group of fruit flies did when they were sent into space. This suggests their levitation technique could be used for long-term research on the effect of zero gravity on living organisms that might help prepare us for longer journeys in space.
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The Long and Fast of It
Sprinter at a starting block (Wikimedia Commons) |
The foot bones and ankle structure of sprinters are different from those of
non-sprinters. In fact the foot and ankle construction in the fastest among
us is similar to that of animals known for their speed, including cheetahs and
greyhounds. According to a new study by Josh Baxter, a graduate student in the Department of
Kinesiology at Penn State University, sprinters have a long fore-foot (the part
in front of the ankle) and reduced leverage in the Achilles tendon. These
characteristics permit sprinters to generate greater contact force between the
foot and the ground and to maintain that force for a longer time. Over a
shorter distance like a sprint, this provides an advantage. It is not clear
whether we are born with these traits or if they are result of training, but it
is hoped that understanding this mechanism in sprinters can be applied to those
who have difficulty walking.
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0