* Dinosaur Speed Demon * Dawn at Vesta * Chivalrous Crickets * Hybrid Humans * Science Fact or Science Fiction: Fluorescent Lights *


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Dinosaur Speed Demon

carnotaurus.pngArtist's impression of a Carnotaurus, Lida Xing and Yi Liu
Carnotaurus was a two-legged, seven-metre-long carnivorous dinosaur that lived in South America.  It had a huge, muscular tail that Scott Persons, a PhD student in the Department of Biological Sciences at the University of Alberta, believes made it one of the fastest running dinosaurs ever.  The unique interlocking construction of the tail bones allowed room for the huge muscle there to expand and contract.  This muscle - called the caudofemoralis muscle - was attached to the upper portion of the legs by tendons.  The tendons helped pull the legs backwards, which provided a boost or propulsion for forward motion; this is where Carnotaurus' speed came from.  One drawback was that the tail was likely rigid, which made turning while chasing prey very difficult.     

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Dawn at Vesta

This past summer, the Dawn spacecraft completed its four-year journey to the asteroid Vesta, the second largest body in the Asteroid Belt.  Dawn then began its mission to map and understand Vesta, which scientists hope will give us new insights into the formation and evolution of the solar system.  According to Dr. Carol Raymond, Deputy Principal Investigator and Project Scientist for the Dawn Mission at the Jet Propulsion Laboratory in Pasadena, California, Vesta turns out to be a visual treat.  It has many dramatic features, including a 400km-wide crater at its south pole, almost as wide as the asteroid itself, with a mountain in the centre that's considerably taller than Everest.
      

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Chivalrous Crickets

cricket.jpg Field Cricket, copyright yug
Mate-guarding is a common phenomenon among insects.  The male will frequently remain close to the female immediately after mating.  This is to ensure that other males do not try to mate with the female.  Scientists also assumed that the male's sometimes aggressive behaviour toward the female was to prevent her from doing the same - moving away to find another mate.  But new research by Dr. Tom Tregenza, a Professor of Evolutionary Biology from The University of Exeter in England, has found that, among field crickets, there is another element to mate-guarding.  In an act of true chivalry, the male cricket will protect the female from predators by allowing her to escape into the burrow first, when under attack - sometimes at the expense of his own life.  It is not entirely altruistic though, as by doing this, the male is protecting the mate carrying his sperm.   

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Hybrid Humans

Homo_sapiens_neanderthalensis.jpgCousin Earl?  Neanderthal Skull, photo copyright Luna04
Who's your daddy? Well, for humans today, it's more complicated than we thought. New genetic analysis of prehistoric fossils has proven that most humans today (outside of Africa) have Neanderthal DNA in their genome - which means our early relatives must have interbred with this now-extinct branch of the human tree. But evidence is also pointing to the possibility that Homo sapiens may have mixed with lots of other extinct hominids, gaining a genetic advantage and then leaving them behind in the evolutionary dust. The most recent studies show that Homo sapiens also interbred with the Denisovans, a previously unknown species of humans that lived at the same time as the Neanderthals. People living in Papua New Guinea today, as well as aboriginal Australians, carry their DNA as well.

Toronto freelance science journalist and author Alanna Mitchell looked into the controversy for Quirks, and spoke with the following people:

Dr. John Hawks is an anthropologist from the University of Wisconsin-Madison, who's working on ancient human DNA. He's been to the cave in Denisova, Siberia, where scientists found a finger bone belonging to an ancient Denisovan. He says these recent discoveries change our understanding of what it means to be human.

Dr. Chris Stringer is one of the world's top authorities on human evolution, and a paleontologist at London's Natural History Museum. He says the new genetic analysis shows we do not have a single origin in Africa, as previously thought. He also says that it could just as easily have been the Neanderthals who lived on, and not us.

Dr. Peter Parham studies the genetics of human immune systems at the Stanford School of Medicine. He says he has found specific genes in people today, related to our immune system, that came from the Neanderthals or the Denisovans. And he believes these genes gave our human ancestors a genetic advantage after they interbred. But the also thinks they might be partly responsible for our auto-immune diseases today.

Dr. David Reich, a geneticist at Harvard's Medical School, compared the Denisovan DNA to that of living humans. He was shocked to discover that the Denisovans lived so recently, and he calls them "the genome in search of an archaeology."  He also points out that this is the first time in the four million years of human history that we've been the only humans on the planet..

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Science Fact or Science Fiction: Fluorescent Lights

This is another episode of our occasional feature, Science Fact or Science Fiction. 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 popular belief comes to us from listener Wanda Batman in Tulsa, Oklahoma, who says, "Leaving fluorescent lights on overnight in an office building is more efficient than turning them on and off". 

To lead us out of the darkness, we contacted Dr. Leo Stocco, from the Department of Electrical and Computer Engineering at the University of British Columbia. He says it is science  fiction.

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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0