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Past Episodes: May 2012 Archives

Saturday May 26, 2012

The Whale's Sixth Sense * Heat Turns Butterfly On * The Ape of Wrath * Squid Ink Writes Its Own History * Before the Lights Go Out
We all know that for both economic and environmental reasons, we have to change the way we consume energy in this country. You'll hear from the author or a new book who has a recipe for conquering the energy crisis before it conquers us. Plus - how climate change is good news for one type of butterfly; why Santino the chimp is a scheming, plotting villain; and what scientists have learned from a 160-million-year-old squid ink pouch. And first of all - A Whale's Sixth Sense.


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Saturday May 19, 2012

*The Beginnings of Art History * Life in the Garbage Patch * Prehistoric Pliosaur Pain * The Bowerbird's Fruitful Foreplay * Exploiting Guppy Love * Octopus on Ice *

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The Beginnings of Art History
white_art.jpg Rock shelter and engraving (inset). Courtesy Randall White

When modern humans moved into Europe about 40,000 years ago, it appears they immediately began to redecorate.  Many caves and rock shelters have been found with sophisticated art in various forms - including engravings, and paintings.  Dr. Randall White, a Canadian anthropologist at New York University, has led a team that's been exploring a site in southern France known as Abri Castenet, a rock shelter that's been explored for nearly a hundred years, but is still revealing new artifacts.  The latest discovery is a huge rock that is part of the collapsed roof, and which, when uncovered, had preserved engravings dating back 37,000 years.  These engravings have been described as symbolic representations of female sexual organs, though Dr. White doesn't necessarily agree with that interpretation.  In any case, this is the oldest reliably dated rock art yet discovered in Europe.
          
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Life in the Garbage Patch
halobates-5b-large.jpg Sea Strider, courtesy Scripps Institution
The North Pacific Gyre is a circulating set of currents that tends to trap floating material and debris.  Over the last forty years an increasing amount of that debris has been non-degrading plastic, often in quite tiny floating fragments, so that the gyre has now become known as the Pacific "Garbage Patch."  Miriam Goldstein, a graduate student, and her colleagues at the Scripps Institution of Oceanography in San Diego, California, voyaged to the garbage patch to investigate the impact that floating plastic fragments were having on the ecosystem.  One of the curious impacts they discovered was that sea skaters, marine insects related to water striders, were taking advantage of the floating plastic, which gave them far more places to lay their eggs.  This is just one change in the deepwater ecosystem that might flag a larger shift.

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Prehistoric Pliosaur Pain

pliosaur_sassoon.JPGDr. Sassoon and the lower jaw of a pliosaur, photo by S Powell
Pliosaurs were marine reptiles that lived 150 million years ago during the Jurassic period.  They were 8 to 9 metres in length, with an elongated head, similar to a crocodile, a short neck, large plump body and four flippers.  It had an extremely powerful jaw with long, sharp teeth.  But a fossilized jaw bone, found in Wiltshire, England in the 1990's, has revealed several unusual conditions in at least one pliosaur.  Dr. Judyth Sassoon, a Paleontologist from The School of Earth Sciences at the University of Bristol in England, discovered that by examining this fossil, she was able to piece together the story of this pliosaur's life.  The fossil showed evidence of erosion in one joint, which is indicative of a form of arthritis.  It also had a crossed jaw.  This resulted in teeth from the upper jaw impacting bone on the lower jaw.  These painful conditions weakened the jaw, eventually causing it to break, which meant the pliosaur was unlikely able to feed again.   
  

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The Bowerbird's Fruitful Foreplay

Spotted Bowerbirds are found in Australia and Papua, New Guinea.  The males are known for their elaborate courtship ritual that begins with the construction of an elaborate bower - a nest-like avenue of carefully arranged sticks on the ground.  The bower is then decorated with many shinny and colourful objects - including a locally found bright green fruit - all designed to attract a mate.  New research by Dr. Joah Madden, a Senior Lecturer from The School of Psychology at the University of Exeter in England, has found that the process of collecting, then discarding, the fruit as it withers is resulting in a form of cultivation.  As the bowerbird clears the area to enhance his display, it is, in fact, helping the seeds from the withered fruit germinate.  It is not clear whether the bowerbird is intentionally propagating fruit in this mutually beneficial behaviour. 
 
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Exploiting Guppy Love

guppy_and_model.jpgPrawn model and guppy.  Courtesy A. De Serrano 
Male Trinidadian Guppies have developed bright orange spots and coloration to attract females of the species.  Research has suggested that orange has evolved as an attractant because the males are exploiting an already existing predilection in the guppies, who are attracted to nutritious orange fruit that occasionally falls into the streams in which they live.  However, a predator may be taking double advantage of this.  A predatory Trinidadian prawn - a crayfish-like shellfish - has developed orange spots on its claws.  Lab experiments by graduate student Alex De Serrano and her colleagues in the department of Ecology and Evolutionary Biology at the University of Toronto, using model prawns, have shown that while prawns without orange spots are avoided by guppies, a little dab of orange paint tends to overcome their natural aversion to the predator.  The orange is a powerful attractant, it seems, promising both sex and food to the guppies.
 
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Octopus on Ice

octopus.JPGTurquet's Octopus. Steve Rupp/National Science Foundation
The ancient ice sheets of Antarctica have given us some of the clearest clues we have into our climate's history.  And many of the models we use to try to understand what the future holds are guided by these frozen clues from the past.  But Dr. Louise Allcock, a geneticist and lecturer in zoology at the National University of Ireland in Galway, has an unorthodox method of unraveling the mysteries of the Antarctic.  She and her team have studied octopus DNA to tell us what happened in the Antarctic in the distant past. They found that the octopuses from the Ross and Weddell Seas, which are now separated by the West Antarctic Ice Sheet and almost 10,000 kms., are genetically almost identical. This finding supports the models that suggest that these two regions may have once been connected, about 200,000 years ago, when the ice sheet last collapsed. 
 
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0


Saturday May 12, 2012

* Smallest Giant * Maya Wall Calendar * Water Striders old Genes * The Nut-Cracker Chimps * White Dwarfs Snack on Planets * Geckos get in a Tailspin *

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The Smallest Giant

Dr. Victoria Herridge, a vertebrate paleontologist from the Natural History Museum in London, was combing through the basements of her museum when she found a fossil tooth discovered more than 100 years ago by pioneering explorer Dorothea Bate.  The tooth, discovered on the Greek island of Crete, had been originally identified as coming from a dwarf elephant.  Dr. Herridge realized that the tooth was, in fact, from a Mammoth.  She retraced the steps of Dorothea Bate to find the original dig in Crete, and found bones from the fossil, which turned out to be the smallest dwarf mammoth ever known - only a bit over a meter tall at the shoulder.  Dwarf pachyderms of several species, it turns out, inhabited islands all over the Mediterranean, one to three-and-a-half million years ago.
          
Related Links
  • Paper in Proceedings of the Royal Society:B
  • Natural History Museum release
  • Nature News
  • Discovery News
  • GRRL Scientist blog in The Guardian
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Maya Wall Calendar
The city of Xultun is an ancient Maya settlement, located in present day Guatemala.  A structure recently excavated there has revealed rare Maya paintings, as well as evidence of astronomical tables relating to various calendrical cycles, including those of the moon, Mars and Venus.  The paintings, found on the inner walls of the structure, depict a Maya King, as well as a scribe holding a stylus.  The astronomical tables - a series of hieroglyphic bars and dots arranged in columns - are also found on the inner walls.  The excavation was recently carried out by Dr. William Saturno, a Professor of Archaeology at Boston University.  He believes the early 9th century structure was the workshop of the scribe depicted in the painting.  These findings are the oldest-known Mayan astronomical tables, as well as the first known instance of Mayan art painted on the walls of a dwelling.
 

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Water Striders Old Genes

waterstrider_2.jpgMale (left) and female (right) Rheumatobates rileyi water strider antennae. Courtesy Science/AAAS
Male water striders always have their antennae out for potential mates, but not to detect them.  Their antennae are elaborately modified into grasping limbs, which are specialized for restraining struggling females during mating.  Dr. Ehab Abouheif, Canada Research Chair in Evolutionary Developmental Biology at McGill University, and his colleagues have worked out the genetic modification that drove the evolution of these complex antennae.  They were then able to "turn back the clock" by reducing the expression of the critical gene at the critical time.  They found males without the antennae elaboration were far less capable of mating than the fully elaborated males.   
  

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The Nut-Cracker Chimps

chimp.jpg© MPI f.Evolutionary Anthropology/Sonja Metzger
Three separate communities of chimpanzees, living the same area of a National Park in the Ivory Coast, have evolved a significant cultural difference.  Lydia Luncz, a PhD student from the Max Plank Institute for Evolutionary Anthropology in Leipzig, Germany, has recently studied each group's preferred method of cracking nuts.  The tool of choice for one group is rocks, while the other two use different sizes of hardwood branches, specifically shaped to hammer open the shell of the Coula nut.  It is believed all the chimps know how to use both tools, but stay with the method that have learned from a parent.  It is also known that when a young female leaves her group to mate with a neighbouring male, she will adopt the nut-cracking method of her mate.  The study shows that cultural differences can arise, even when the groups are genetically the same and in the same ecological niche.
 
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White Dwarfs Snack on Planets

white_dwarf_eating.jpgArtist's impression of a white dwarf surrounded by rocky dust cloud. 
As stars like our Sun age, they grow into Red Giants as they slowly exhaust their hydrogen and helium fuel.  Then, when the fuel is all gone, they blow off their outer shells and a super-dense, slowly cooling husk called a White Dwarf is all that remains.  Using the Hubble Space Telescope, Professor Boris Gänsicke of the Department of Physics at the University of Warwick, and his colleagues, have found four white dwarf stars that appear to be snacking on a continuous flow of dust.  The dust consists of oxygen, carbon, and metals like silicon, iron and magnesium, which are the primary constituents of terrestrial planets like the Earth.  Prof. Gänsicke suspects that gravitational disturbances due to the changing mass of the star may have caused collisions between the planets orbiting these stars, shattering them.  Now all that is left is the dust that the stars are slowly accreting.
 
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Geckos Get in a Tailspin

leopard_gecko.jpgLeopard Gecko, copyright Jerome66
The leopard gecko is common in the desert regions of Pakistan and Iran.  It is one of the larger geckos, measuring from about 20 to 28 centimetres in length, including its tail.  The gecko exhibits an unusual behavioural trait known as autotomy - voluntarily choosing to lose an appendage.  In this case, that appendage is the tail.  When a predator attacks, a combination of muscle spasms as well as a fracture in the tail-bone allow the tail to be jettisoned quickly.  The gecko is able to escape for a couple of reasons.  It is lighter and faster without a tail, but also because the tail is able to keep moving and create a distraction.  Dr. Anthony Russell, a professor of Biological Sciences at the University of Calgary, has discovered that electrical activity in the tail allows muscles to keep firing for up to 30 minutes.  As the tail jumps and flips and distracts the predator, the gecko is able to reach safety. 
 
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0