Sightless Cave Fish Demonstrate Evolutionary Advantage.
In the rivers and caves of Sierra de El Abra, Mexico, cave fish that never see the light of day have evolved without eyes or pigmentation. These fish are believed to “have had at least five separate evolutionary origins from these two ancestral stocks.” What is puzzling, however, is why the sightless cave fish maintain their sightlessness despite the fact that interbreeding with normal cousin surface fish is common. According to scientists at NYU’s Cave Biology Group, cave fish maintain their genetic predisposition for sightlessness, despite interbreeding, because there must exist some adaptive advantage to remaining sightless in a dark world.
Read more at Science Daily.
Wolf Pair Repopulates German Saxony.
The forests of southeast Germany lost their wolf population to human predation. Ten years ago, a pair of wolves from the Sudeten Mountain region of Poland traveled to this region. Since then, the fertile couple has been singly responsible for re-populating the German forests in this region. Named One-eye and Sunny, the pair had been radio-tagged years ago, so that their movements have been carefully watched by scientists. The wolf is a protected species in Germany, and it is believed that the large populations of deer in the area could support hundreds of wolf packs.
Read more on Global Animal.
Early Wolf Domestication Was Geographically Diverse.
A 33,000 year old wolf fossil from Siberia is lending support to the theory that the domestication of wolves took place over a long period of time and occurred at multiple locations simultaneously. In this case, the fossil indicates a wolf that was in the early stages of domestication, which is typically marked by a shortening of the snout and crowding of teeth. A similar fossil, found in Belgium, was in approximately the same stage of semi-domestication. Since these particular individuals were unlikely to have survived the last glacial event, it underscores the recurrent nature of human/wolf domestication.
Read more at Red Orbit.
New Iridescent Blind Mole Poses Puzzle.
A recent publication in the Royal Society Biology Letters announces the discovery of iridescent moles. With the exception of the eyes of nocturnal animals, no other mammals display iridescence. But this poses a question: why would iridescence occur in animals such as moles, which are blind? It is true that moles evolved from sighted ancestors, but that does not explain the benefit to maintaining their sparkling coats. On the other hand, since iridescence may simply be the byproduct of the geometrical structure of the layered fur, it might not play a significant evolutionary role at all.
Read more at Yahoo.
The Mother of All Thoroughbreds.
Utilizing DNA analysis from some 600 horses representing several regions and continents, scientists believe they have determined the original horse that conferred special speed on its descendants. To obtain the proper DNA, the scientists had to extract it not only from live horses, but also from the bones of dead thoroughbreds, and even “from 40 donkeys and two zebras.” The founder speed horse was a mare that likely lived in Britain some 300 years ago. In modern times, a variant of the “speed gene” developed, and can be traced back to two well-known champions, Nearctic and his son, Northern Dancer.
Read more at University College of Dublin.
Did Bonobos Self-Domesticate?
In Scientific American, a controversial new theory posits that bonobos became a calmer, more domesticated version of chimps because their environment permitted a longer maturation period. According to Brian Hare of Duke University, the region south of the Congo region is where bonobos ancestors lived – chimpanzee ancestors lived on the north side of the river. Because the bonobos faced fewer threats from predators than did chimpanzees, Hare believes that they evolved more domesticated features and behaviors. Indeed, bonobos are considerably less aggressive than chimps, are smaller, mature more slowly and have shorter fangs. Hare also points out that domestication of dogs by humans produced similar traits. Other bonobo experts do not buy Hare’s theory, however, and in fact proving it may be very difficult.
Fat or Lean, the Bottom Line Is Survival.
A study carried out by the Andrew Higginson of Bristol University’s School of Biological Sciences reveals that the amount of fat different animals carry is a function of the optimal ratio of fat to muscle for that particular animal’s behavior. For example, more fat would allow the animal to avoid starvation in difficult times, but also would cause it to become slower and more vulnerable to predators. The study’s author summed up the findings this way: “Bats fly and so have high costs of carrying extra weight, whilst carnivores spend much of their time resting and so will use less energy than busy scurrying rodents.” Unfortunately, none of this sheds much light on the human struggle with weight.
Read more at Discovery.
Proteins Become Photogenic.
At the Lawrence Berkeley National Laboratory scientists are using a cryo-electron microscope to take photographs of individual proteins in 3-D. The machine, which costs $1.5 million, operates at the temperature of liquid nitrogen. This low temperature allows soft matter, such as protein, to be imaged in 3-D for the first time. Multiple images of the protein must be taken in order to create the 3-D effect.
Read more at Berkeley Lab.
Black Feathers on Archaeopteryx Support Flying Ability.
Using sophisticated electron microscope techniques, scientists believe they have discovered additional proof that Archaeopteryx, the much photographed winged dinosaur, had black feathers. Why is that important? Apparently, in modern birds, pigmented structures in the feathers not only provide color but actually give the wing the additional strength it needs for flight. These pigmented cells, called melanosomes, could be seen in significant number in Archaeopteryx’s fossilized feathers using the new microscopy technique. While this does not prove that the creature could fly, it adds to the ever growing body of proof that it could.
Read more at the Daily Mail.
Tongue Twister of an Expedition Lands 40 New Species.
Known as the Kwamalasamutu expedition, researchers looking for new species of animals near Kwamalasamutu, Suriname, South America, seem to have hit the jackpot. The new species include many new fish, frogs and insects. The links below are a treasure trove of new pictures and videos about the finds.
Read more at Red Orbit.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.