Marvelous Monday arrives once again here in Possum Valley and the time has arrived for science talk. New discoveries, new takes on old knowledge, and other bits of news are all available for the perusing in today's information world. Over the fold are selections from the past week from a few of the many excellent science news sites around the world. Today's tidbits include T. rex's killer smile revealed, most invasive plants grow in areas with a climate similar to their native origin, why humans began to walk upright, new light shed on wandering continents, monarch butterfly numbers continue to drop, and Venice hasn't stopped sinking after all. Pull up that comfy chair and grab a spot in the sun. There is always plenty of room for everyone. Another session of Dr. Possum's science education, entertainment, and potluck discussion is set to begin.
Featured Stories
A prominent feature of T. rex skeletons on display in museums around the world is the array of teeth made for ripping flesh.
(Researcher) Reichel analyzed the teeth of the entire tyrannosaurid family of meat-eating dinosaurs and found T. rex had the greatest variation in tooth morphology or structure. The dental specialization was a great benefit for a dinosaur whose preoccupation was ripping other dinosaurs apart.
Reichel’s research shows that the T. rex’s front teeth gripped and pulled, while the teeth along the side of the jaw punctured and tore flesh. The teeth at the back of the mouth did double duty: not only could they slice and dice chunks of prey, they forced food to the back of the throat.
For
invasive plants the climate is a determining factor in their choice of new habitat.
With the rise of European explorers and their discoveries of new geographic territories, five centuries ago, plant and animal species were moved by humans, accidentally or voluntarily, to places where they never existed before. Some species proliferated at the expense of local ones, menacing not only the equilibrium of the invaded ecosystems, but also causing serious socio-economic problems such as loss of crop productivity or an increase in allergies among the human population. However, these species provide the unique opportunity to understand ecological and evolutionary mechanisms that enable them to develop efficiently and rapidly in new regions.
We
humans walk upright and take the activity for granted. The stance may have originated millions of years ago as an adaptation to handle scarce resources.
The research findings suggest that chimpanzees switch to moving on two limbs instead of four in situations where they need to monopolize a resource, usually because it may not occur in plentiful supply in their habitat, making it hard for them to predict when they will see it again. Standing on two legs allows them to carry much more at one time because it frees up their hands. Over time, intense bursts of bipedal activity may have led to anatomical changes that in turn became the subject of natural selection where competition for food or other resources was strong.
The
shifting of Earth's continents over millions of years may be the result of a layer of partially molten rock about 22 to 75 miles underground.
The slow slide of Earth's continents results from plate tectonics. Our planet is more than four billion years old, and over this time, the forces of plate tectonics have carried continents many thousands of miles, forging mountain ranges when they collided and valleys that sometimes filled with oceans when they were torn apart. This continental drift could also have changed the climate by redirecting currents in the ocean and atmosphere.
The outermost layer of Earth, the lithosphere, is broken into numerous tectonic plates. The lithosphere consists of the crust and an underlying layer of cool and rigid mantle. Beneath the oceans, the lithosphere is relatively thin (about 65 miles), though beneath continents, it can be as thick as 200 miles. Lying beneath the lithosphere is the asthenosphere, a layer of rock that is slowly deforming and gradually flowing like taffy. Heat in Earth's core produced by the radioactive decay of elements escapes and warms mantle rocks above, making them softer and less viscous, and also causes them to convect. Like the circulating blobs in a lava lamp, rock in the mantle rises where it is warmer than its surroundings, and sinks where it's cooler. This churn moves the continental plates above, similar to the way a raft of froth gets pushed around the surface of a simmering pot of soup.
The
numbers of monarch butterflies continues to decline year by year.
...reports by the World Wildlife Fund, private donors and Mexico’s Michoacan state show that Monarch numbers will be down almost 30 percent in 2012 as they make their annual trek from their breeding grounds in Mexico and move across Texas.
The figures show an alarming decades-long decline in their numbers.
The water in
Venice continues to rise year by year and is not only the result of rising ocean levels but the city itself is sinking still.
In the new study, using the GPS instruments, (researcher) Bock and his colleagues were able to take absolute readings of the city and its surrounding lagoons. And not only did they find the sinking, but they found that the area was tilting a bit, about a millimeter or two eastward per year. That means the western part – where the city of Venice is – is higher than the eastern sections. Prior satellite analyses didn’t pick up on the tilt, Bock said, possibly because the scientists had been taking measurements using InSAR, which only provided the change elevation relative to other sites.
The relative nature of InSAR measurements might also explain why the new study detected Venice’s subsidence, while other recent studies did not, Bock conjectured.
Other Worthy Stories of the Week
Climate change acceptance sinks during economic slump
Dawn chorus, primeval forest and jaguars at night: Listen to Nature's chorusAudio slideshow
Two new NASA Lunar Reconnaissance Orbiter videos: See the Moon's evolution and take a tour
Warm weather puts trees on fast forward
Beer and bling in Iron Age Europe
Research offers a new way to see inside solids
First high resolution pictures of the wreck of the Titanic
Planet Mercury even weirder than we thought
Spotting ancient sites from space
Hints at how the universe got its magnetism
Brown liquor and solar cells to provide sustainable electricity
An extinct species of Scoops owl discovered in Madeira
Graphene produced by using microorganisms from an ordinary river
Waterless approach to microchip making touted as groundbreaking
The dark side of Facebook
For even more science news:
General Science Collectors:
Alpha-Galileo
BBC News Science and Environment
Eureka Science News
LiveScience
New Scientist
PhysOrg.com
SciDev.net
Science/AAAS
Science Alert
Science Centric
Science Daily
Scientific American
Space Daily
Blogs:
A Few Things Ill Considered Techie and Science News
Cantauri Dreams space exploration
Coctail Party Physics Physics with a twist.
Deep Sea News marine biology
Laelaps more vertebrate paleontology
List of Geoscience Blogs
ScienceBlogs
Space Review
Techonology Review
Tetrapod Zoologyvertebrate paleontology
Science Insider
Scientific Blogging.
Space.com
Wired News
Science RSS Feed: Medworm
The Skeptics Guide to the Universe--a combination of hard science and debunking crap
At Daily Kos:
This Week in Science by DarkSyde
Overnight News Digest:Science Saturday by Neon Vincent. OND tech Thursday by rfall.
Pique the Geek by Translator Sunday evenings about 9 Eastern time
All diaries with the DK GreenRoots Tag.
All diaries with the eKos Tag
A More Ancient World by matching mole
Astro Kos
SciTech at Dkos.
Sunday Science Videos by palantir
NASA picture of the day. For more see the NASA image gallery or the Astronomy Picture of the Day Archive
Orion's Rainbow of Infrared Light, NASA, Public Domain