Lizards Use Third Eye to Steer by the Sun

A series of clever experiments into the reptilian “third eye” has confirmed that lizards use this patch of light-sensitive cells as a sun-calibrated compass.

To test how third eyes — technically known as parietal eyes — help them find their way, biologists first trained Italian wall lizards to swim from the center of a small outdoor swimming pool to a hidden ledge at its edge. A fence was erected around the pool, so that the only visual point of reference was the position of the sun. The lizards passed the test.

The researchers next put groups of lizards in three artificially lit rooms for a week. In the control room, lights brightened and dimmed in sync with the rise and fall of day. Lights in the other rooms were set out of sync, causing the lizards’ body clocks to be artificially sped up or slowed down by six hours.

When tested in the pool, only lizards from the control group could find the ledge. Depending on the state of their body clock, the others swam too far to the left or right, as would be expected if they’d used the sun to navigate and were now confused by the disjunction between the sun’s location and where they expected it to be.

Finally, the researchers covered the lizards’ third eyes with paint or — in a later, more gruesome iteration — removed their third eyes altogether. In both cases, the lizards swam in random directions, no longer able to navigate at all.

Original article here.

Single molecule, one million times smaller than a grain of sand, pictured for first time

It may look like a piece of honeycomb, but the above lattice-shaped image is the first ever close-up view of a single molecule.

Scientists from IBM used an atomic force microscope (AFM) to reveal the chemical bonds within a molecule. Below is a picture of the scientists next to the AFM:



The researchers focused on a single molecule of pentacene, which is commonly used in solar cells. The rectangular-shaped organic molecule is made up of 22 carbon atoms and 14 hydrogen atoms.

In the image above the hexagonal shapes of the five carbon rings are clear and even the positions of the hydrogen atoms around the carbon rings can be seen.

To give some perspective, the space between the carbon rings is only 0.14 nanometers across, which is roughly one million times smaller than the diameter of a grain of sand.

Below is a textbook model computer-generated image of how we're used to seeing a molecule represented with balls and sticks:



To the right is a 3D view showing how a single carbon monoxide molecule was used to create the image using a 'tuning fork' effect.

The team from IBM Research Zurich said the results could have a huge impact of the field of nanotechnology, which seeks to understand and control some of the smallest objects known to mankind.

The AFM uses a sharp metal tip that acts like a tuning fork to measure the tiny forces between the tip and the molecule. This requires great precision as the tip moves within a nanometer of the sample.

Read more in the original article here.

From Stem Cells to Tooth In the Mouth of a Mouse

Researchers used stem cells to grow a replacement tooth for an adult mouse, the first time scientists have developed a fully functioning three-dimensional organ replacement, according to a report in the Proceedings of the National Academy of Sciences. The researchers created a set of cells that contained genetic instructions to build a tooth, and then implanted this “tooth germ” into the mouse’s empty tooth socket. The tooth grew out of the socket and through the gums, as a natural tooth would. Once the engineered tooth matured, after 11 weeks, it had a similar shape, hardness and response to pain or stress as a natural tooth, and worked equally well for chewing. The researchers suggested that using similar techniques in humans could restore function to patients with organ failure.

Original article here.

Mysterious Tubular Clouds

Above: These long clouds -- known as Morning Glory clouds -- can grow to be 600 miles long and can move at up to 35 miles per hour, causing problems for aircraft even on windless days.

The appear every fall over Burketown, Queensland, Australia, a remote town with fewer than 200 residents. A small number of pilots and tourists travel there each year in hopes of “cloud surfing” with the mysterious phenomenon.

Similar tubular shaped clouds called roll clouds appear in various places around the globe. But nobody has yet figured out what causes the Morning Glory clouds.

Original article here.

Early Life Didn’t Just Divide, It United

A massive analysis of almost every bacterial genome sequenced to date suggests a new shape for the tree of life. One of its core branches appears to be a union of two other branches. Descendants of that line became the energy centers of plant and animal cells.

The details of early cellular evolution are murky, with few fossils having remained intact for the billions of years since self-replicating chemicals assumed cellular form. But at a general level, scientists know that the earliest organisms were single-celled, nucleus-lacking creatures called prokaryotes.

These are broken down into five groups: bacteria, archaea, clostridia, actinobacteria and so-called gram-negative bacteria. To most people, prokaryotes are just a bunch of microscopic bugs, but to microbiologists they’re as richly varied as the animal kingdom.

Scientists think the first eukaryotes — single-celled creatures with nuclei and complex internal structures, from which the entire plant and animal kingdom descended — evolved from prokaryotes, with some prokaryotes absorbed wholesale into these new and complicated organisms.

The best-known examples of this absorption are mitochondria and chloroplasts, the structures that generate energy in animal and plant cells. Both belong to the gram-negative class, as do cyanobacteria, which several billion years ago probably transmuted Earth’s early atmosphere from a toxic soup to oxygen-rich air through photosynthesis.

According to scientists, the origin of this gram-negative group is not singular. Instead it appears to have been produced through a fusion of actinobacteria and clostridium. Were mammals derived from a union of insect and amphibian, the story-of-life rearrangement would be comparably profound.

The scientist's hypothesis is based on pattern analyses run on the genome sequences of more than 3,000 types of bacteria. For three years, he refined algorithms that teased out relationships between the different genes, then proposed different taxonomies to explain them.

The union likely took the form of endosymbiosis, in which one of the prokaryotes literally swallowed the other, and the two grew together.

Read more about the hypothesis in the original article here.

Wired's Best Science Visualization Videos of 2009

Below are several examples of Wired's best science visualization videos of 2009.









For more videos, see the original article here.

The Strangest Things Pulled Out of Peat Bogs

A few thousand years ago, someone living in what is now Ireland made some butter, stuck it into an oak barrel, wandered out into a bog about 25 miles west of Dublin, and buried it.

Somehow, that someone lost track of it, which two lucky archaeologists discovered when they dug up the stashed loot earlier this year in the Gilltown bog, between the Irish towns of Timahoe and Staplestown.

But that wasn’t the first keg of butter that’s been preserved by the strange chemistry of the bog. More than 270 kegs of bog butter have been retrieved from the wetlands, along with dozens of ancient bodies, swords, and ornaments.

For a brief overview of what bogs are and how they work, see this prior blog post.

Below are some examples from a recent Wired article of some of the strangest things that scientists and citizens have pulled from the peat.

All kinds of bodies have been found with their skin and organs intact. The objects are preserved by the remarkable properties of Sphagnum mosses, which come with preservatives built into their cell walls. After they die, they decay very slowly. and anything that falls into the Sphagnum peat bogs decays more slowly, too.



Murder weapons are a common find. Archaeologists believe the bogs were sites for ritual sacrifices, because many of the bodies appear to have been tortured or “overkilled.” In the picture (above) of a find named Yde girl, you can see the cord that was used to strangle her. Tollund Man suffered a similar fate: A noose was found around his neck.



Murder wasn’t all that happened out on the bogs. Multiple trepanated skulls, that is to say, skulls with holes drilled in them, have been found. Based on the use of the procedure in medieval times, one hypothesis is that the “operation may have been performed to remove a blood clot or a less-tangible thing like a spirit” from an individual. Even now, there’s still a small number of people who think drilling holes in their skulls is therapeutic.



For other examples of items found in bogs, see the original article here.

New species of worms release 'bombs'

Thousands of feet beneath the sea are live worms that can cast off green glowing body parts, a move scientists think may be a defensive effort to confuse attackers.

Researchers have dubbed the newly discovered critters "green bombers."

Ranging in size from three-fourths of an inch to nearly four inches, the worms live at depths of 5,900 feet to more than 12,000 feet and were discovered by remotely operated submarines in both the northeast and western Pacific Ocean.

They have a strange way of using bioluminescence. They have appendages, some round, others oval or long, which they release when they are disturbed. Once they release the appendage, it glows bright green.

Original article here.

New Species in Eastern Himalayas

Over the past decade, more than 350 new species have been discovered in the Eastern Himalayas, according to a new report by scientists working for the WWF.

The WWF report, "The Eastern Himalayas -- Where Worlds Collide," details discoveries made by scientists from various organizations between 1998 and 2008 in a region reaching across Bhutan and northeast India to the far north of Myanmar as well as Nepal and southern parts of Tibet in China.

The report describes more than 350 new species discovered, including 244 plants, 16 amphibians, 16 reptiles, 14 fish, two birds, two mammals and at least 60 new invertebrates.

The Eastern Himalayas harbor a staggering 10,000 plant species, 300 mammal species, 977 bird species, 176 reptiles, 105 amphibians and 269 types of freshwater fish. The region also has the highest density of Bengal tigers in the world and is the last bastion of the charismatic greater one-horned rhino.

Below are some pictures of the various new species taken from this gallery.

A male Gumprecht's green pitviper:



Orange-spotted snakehead (Channa aurantimaculata), endemic to the forest streams, ponds, and swamps adjacent to the Brahmaputra river in northern Assam:



Asian Babbler:



The miniature muntjac, also called the "leaf deer," which is the world's oldest and smallest deer species. Scientists initially believed the small creature was a juvenile of another species but DNA tests confirmed it was a new species:



Naung Mung scimitar-babbler:



Zaw's wolf snake:



Flying frog (Rhacophorus suffry):



Original article here. WWF report here.

Giant carnivorous plant found

In a coincidental follow-up to yesterday's post, a new species of giant carnivorous plant has been discovered in the highlands of the central Philippines.

The pitcher plant is among the largest of all pitchers and is so big that it can catch rats as well as insects in its leafy trap. Botanists have named the pitcher plant after British natural history broadcaster David Attenborough (Nepenthes attenboroughii).

Pitcher plants are carnivorous. Carnivorous plants come in many forms, and are known to have independently evolved at least six separate times. While some have sticky surfaces that act like flypaper, others like the Venus fly trap are snap traps, closing their leaves around their prey.

Pitchers create tube-like leaf structures into which insects and other small animals tumble and become trapped.

The pitcher plant does not appear to grow in large numbers, but McPherson hopes the remote, inaccessible mountain-top location, which has only been climbed a handful of times, will help prevent poachers from reaching it.

During the expedition, the team also encountered another pitcher, Nepenthes deaniana, which had not been seen in the wild for 100 years. The only known existing specimens of the species were lost in a herbarium fire in 1945.

On the way down the mountain, the team also came across a striking new species of sundew, a type of sticky trap plant, which they are in the process of formally describing. Thought to be a member of the genus Drosera, the sundew produces striking large, semi-erect leaves which form a globe of blood red foliage.

Original article here.

Tiny Ecosystems in Bowels of Carnivorous Plants

For insight into complex ecological dynamics, one Harvard University biologist peers into the cupped leaves of carnivorous pitcher plants.

At the bottom of each slippery-sided leaf is a pool of water into which unlucky insects fall and drown. The bugs sustain not only the plant, but an intricate food web of bacteria, plankton and invertebrates. Each pool is small enough to fit in a shot glass, and big enough to model the world.

According to the scientist, each leaf is its own "individual lake, its own individual ecosystem. Suddenly, in a bog I can walk to from my office, I’ve got 50,000 lakes to do experiments on. This is an opportunity to understand how a complete, functioning natural ecosystem works.”

Understanding how ecosystems work is an important but challenging task for scientists. Though patterns can be described — nutrient levels shift, an animal population grows, another shrinks — it can be hard to know what’s coincidental and what’s linked.

If researchers can run experiments on an ecosystem, measuring exactly what goes in and out, tweaking different aspects and seeing what happens, then they can better decipher its underlying rules.

However, it’s not easy to replicate nature. Ecologists have had some success studying islands and lakes, which are fairly self-contained, and extrapolating those findings to the rest of the natural world.

For the last fifteen years, scientists slogged through the bogs of New England, studying the life that exists in each pool. At the very base are bacteria, which support phytoplankton and cytoplankton, which support single-celled animals, which support fly larvae. All of it relies on nutrients delivered by drowning bugs.

There are four or five trophic levels in a pitcher plant, just like there are four or five trophic levels in a lake.

Fly larvae are the top-level predator in the pitcher, the analogues of tigers or wolves. They’re what ecologists call a “keystone” species, who control the abundance every other species, but require a habitat of sufficient size to support those other creatures.

Original article here.

Ferocious Swimming Tiger

Although most cats big and small are not fans of the water, tigers love it and actively seek it out as a means to cool themselves during the extreme heat of the day in much of Asia. Tigers are powerful swimmers, capable of traveling up to 4 miles in the water and commonly seen carrying their kills across lakes.

The pictures below are from a gallery of Odin, a white Bengal tiger living in Six Flags Discovery Kingdom Zoo near San Francisco. White tigers are incredibly rare in the wild. There are dozens in zoos, but with the inbreeding of these popular beasts to preserve their special trait, white tigers are more likely to be born with physical defects.

Every year, the north Atlantic ocean turns green with plankton, and for more than fifty years, scientists thought they knew why. Now, a decade’s worth of satellite measurements suggest they were wrong.

The common-sense idea is that in the spring, the sun warms up the water column until it hits a key threshold and suddenly comes alive. But the true beginning of the plankton blooms probably begins in the dark of winter.

Phytoplankton harness the energy of the sun and draw on nutrients in the ocean like nitrogen, iron, and other elements that land plants get from soil. So scientists focused on solar and nutrient availability as the key to their growth. But they found that the phytoplankton's growth rate started to accelerate in mid-winter, when the conditions for their growth were presumably the worst.

Scientists devised an alternative thesis that squares better with the new data. During the winter months, cold winds blowing across the water cool the top surface layers. Cold water sinks, pushing up some warmer water, which gets cooled itself and drops. The process creates convection and carries the tiny plankton through a much larger volume of the ocean, diluting them.

When the phytoplankton are spread out, it’s harder for the zooplankton that eat them to find them. Suddenly, the phytoplankton can breed like crazy without as much interference by predators. As spring arrives, the temperature of the surface water and the layers underneath it equalize. The convection stops. The water stops mixing. At that moment — when the phytoplankton get stuck at the top of the ocean — we notice the blooms.

If the new thesis is right, the new model would have dramatic implications for ocean health in a warming world. If a warmer ocean is all that’s needed to spark plankton blooms, then global warming would lead to larger and larger blooms. With the new model, a warming ocean would hurt the blooms. Considering that the blooms are the base of the oceanic food chain, that would hurt species ranging from the tiniest fish to the largest whales.

Original article here.

Ancient spiders yield 3D secrets

Ancient fossilized, spider-like species have been imaged in 3D using thousands of X-ray scans and imaging software.

The two species, Cryptomartus hindi and Eophrynus prestvicii, lived 300 million years ago but are closely related to modern spiders.

The 3D images show that C. hindi grasped at prey with its front legs and E. prestivicii had defensive spikes on its back.

The 3D images were obtained by using a computed tomography scanner - a device that can take X-ray images from many angles.

Some 3,000 images of each fossil were obtained, and a custom software package developed at Imperial College London was used to assemble the images into a single, detailed, 3D virtual model of the creatures.

The researchers suggest that the animal probably was an "ambush predator" like the modern-day crab spider, lying in wait for prey to come close.

Another finding from the models is that E. prestivicii had hard spikes along its back, probably as a defensive measure making it less palatable to the amphibians that would have hunted it.

Click on the below images to be taken the web page with videos of the 3D renderings:





Original articles here and here.