Origin of Photosynthesis Revealed

Atmospheric oxygen really took off on our planet about 2.4 billion years ago during the Great Oxygenation Event. At this key juncture of our planet's evolution, species had either to learn to cope with this poison that was produced by photosynthesizing cyanobacteria or they went extinct. It now seems strange to think that the gas that sustains much of modern life had such a distasteful beginning.

So how and when did the ability to produce oxygen by harnessing sunlight enter the eukaryotic domain, that includes humans, plants, and most recognizable, multicellular life forms? One of the fundamental steps in the evolution of our planet was the development of photosynthesis in eukaryotes through the process of endosymbiosis.

This crucial step forward occurred about 1.6 billion years ago when a single-celled protist captured and retained a formerly free-living cyanobacterium. This process, termed primary endosymbiosis, gave rise to the plastid, which is the specialized compartment where photosynthesis takes place in cells. Endosymbiosis is now a well substantiated theory that explains how cells gained their great complexity and was made famous most recently by the work of the late biologist Lynn Margulis, best known for her theory on the origin of eukaryotic organelles.

In a paper "Cyanophora paradoxa genome elucidates origin of photosynthesis in algae and plants" that appeared this week in the journal Science, an international team led by evolutionary biologist and Rutgers University professor Debashish Bhattacharya has shed light on the early events leading to photosynthesis, the result of the sequencing of 70 million base pair nuclear genome of the one-celled alga Cyanophora.

In the world of plants, "Cyanophora is the equivalent to the lung fish, in that it maintains some primitive characteristics that make it an ideal candidate for genome sequencing," said Bhattacharya.

Bhattacharya and colleagues consider this study "the final piece of the puzzle to understand the origin of photosynthesis in eukaryotes." Basic understanding of much of the subsequent evolution of eukaryotes, including the rise of plants and animals, is emerging from the sequencing of the Cyanophora paradoxa genome, a function-rich species that retains much of the ancestral gene diversity shared by algae and plants.

For those unfamiliar with algae, they include the ubiquitious diatoms that are some of the most prodigious primary producers on our planet, accounting for up to 40% of the annual fixed carbon in the marine environment.

Bhattacharya leads the Rutgers Genome Cooperative that has spread the use of genome methods among university faculty. Using data generated by the Illumina Genome Analyzer IIx in his lab, Bhattacharya, his lab members Dana C. Price, Cheong Xin Chan, Jeferson Gross, Divino Rajah and collaborators from the U.S., Europe and Canada provided conclusive evidence that all plastids trace their origin to a single primary endosymbiosis.

Read more at Science Daily

Humans Are Not Naturally 'Nasty'

Biological research increasingly debunks the view of humanity as competitive, aggressive and brutish, a leading specialist in primate behavior told a major science conference Monday.

"Humans have a lot of pro-social tendencies," Frans de Waal, a biologist at Emory University in Atlanta, told the annual meeting of the American Association for the Advancement of Science.

New research on higher animals from primates and elephants to mice shows there is a biological basis for behavior such as cooperation, said de Waal, author of "The Age of Empathy: Nature's Lessons for a Kinder Society."

Until just 12 years ago, the common view among scientists was that humans were "nasty" at the core but had developed a veneer of morality -- albeit a thin one, de Waal told scientists and journalists from some 50 countries.

But human children -- and most higher animals -- are "moral" in a scientific sense, because they need to cooperate with each other to reproduce and pass on their genes, he said.

Research has disproved the view, dominant since the 19th century, typical of biologist Thomas Henry Huxley's argument that morality is absent in nature and something created by humans, said de Waal.

And common assumptions that the harsh view was promoted by Charles Darwin, the so-called father of evolution, are also wrong, he said.

"Darwin was much smarter than most of his followers," said de Waal, quoting from Darwin's "The Descent of Man" that animals that developed "well-marked social instincts would inevitably acquire a moral sense or conscience."

De Waal showed the audience videos from laboratories revealing the dramatic emotional distress of a monkey denied a treat that another monkey received; and of a rat giving up chocolate in order to help another rat escape from a trap.

Such research shows that animals naturally have pro-social tendencies for "reciprocity, fairness, empathy and consolation," said de Waal, a Dutch biologist at Emory University in Atlanta, Georgia.

"Human morality is unthinkable without empathy."

Read more at Discovery News

Hubble Reveals Weird New Exoplanet: Waterworld

Would Kevin Costner's character in the movie "Waterworld" be at home on this exoplanet?

The planet GJ 1214b was discovered in 2009 and was one of the first planets where an atmosphere was detected. In 2010, scientists were able to measure the atmosphere, finding it was likely composed mainly of water.

Now, with infrared spectra taken during transit observations by the Hubble Space Telescope, scientists say this world is even more unique, and that it represents a new class of planet: a waterworld underneath a thick, steamy atmosphere.

"GJ 1214b is like no planet we know of," said Zachary Berta of the Harvard-Smithsonian Center for Astrophysics (CfA). "A huge fraction of its mass is made up of water."

GJ 1214b is a super-Earth -- smaller than Uranus but larger than Earth -- and is about 2.7 times Earth's diameter, weighing almost seven times as much. This world is also hot: it orbits a red-dwarf star every 38 hours at a distance of 2 million kilometers, giving it an estimated temperature of 230 degrees Celsius.

Berta and a team of international astronomers used Hubble's Wide Field Camera 3 (WFC3) to study GJ 1214b when it crossed in front of its host star. During such a transit, the star's light is filtered through the planet's atmosphere, giving clues to the mix of gases.

"We're using Hubble to measure the infrared color of sunset on this world," Berta said.

Hazes are more transparent to infrared light than to visible light, so the Hubble observations help to tell the difference between a steamy and a hazy atmosphere. They found the spectrum of GJ 1214b to be featureless over a wide range of wavelengths, or colors. The atmospheric model most consistent with the Hubble data is a dense atmosphere of water vapor.

Since the planet's mass and size are known, astronomers can calculate the density, of only about 2 grams per cubic centimeter. Water has a density of 1 gram per cubic centimeter, while Earth's average density is 5.5 grams per cubic centimeter. This suggests that GJ 1214b has much more water than Earth does, and much less rock.

As a result, the internal structure of GJ 1214b would be extraordinarily different from that of our world.

"The high temperatures and high pressures would form exotic materials like 'hot ice' or 'superfluid water', substances that are completely alien to our everyday experience," Berta said.

Read more at Discovery News

It's Alive! Pleistocene Plant Blooms Again

Fruit seeds stored away by squirrels more than 30,000 years ago and found in Siberian permafrost have been regenerated into full flowering plants by scientists in Russia, a new study has revealed.

The seeds of the herbaceous Silene stenophylla are far and away the oldest plant tissue to have been brought back to life, according to lead cryologists Svetlana Yashina and David Gilichinsky of the Russian Academy of Sciences.

The latest findings could be a landmark in research of ancient biological material and the race to potentially revive other species, including some that are extinct.

And they highlight the importance of permafrost itself in the "search of an ancient genetic pool, that of preexisting life, which hypothetically has long since vanished from the earth's surface," they wrote.

The previous record for viable regeneration of ancient flora was with 2,000-year-old date palm seeds at the Masada fortress near the Dead Sea in Israel.

The latest success is older by a significant order of magnitude, with researchers saying radiocarbon dating has confirmed the tissue to be 31,800 years old, give or take 300 years.

The study, in today's issue of the Proceedings of the National Academy of Sciences, described the discovery of 70 squirrel hibernation burrows along the bank of the lower Kolyma river, in Russia's northeast Siberia, and bearing hundreds of thousands of seed samples from various plants.

"All burrows were found at depths of 20-40 meters (65 to 130 feet) from the present day surface and located in layers containing bones of large mammals such as mammoth, wooly rhinoceros, bison, horse, deer, and other representatives of fauna" from the Late Pleistocene Age.

The permafrost essentially acted as a giant freezer, and the squirreled-away seeds and fruit resided in this closed world -- undisturbed and unthawed, at an average of -7 degrees Celsius (19 Fahrenheit) -- for tens of thousands of years.

Scientists were able to grow new specimens from such old plant material in large part because the burrows were quickly covered with ice, and then remained "continuously frozen and never thawed," in effect preventing any permafrost degradation.

In their lab near Moscow, the scientists sought to grow plants from mature S. Stenophylla seeds, but when that failed, they turned to the plant's placental tissue, the fruit structure to which seeds attach, to successfully grow regenerated whole plants in pots under controlled light and temperature.

"This is an amazing breakthrough," Grant Zazula of the Yukon Paleontology Program at Whitehorse in Yukon Territory, Canada, told The New York Times.

"I have no doubt in my mind that this is a legitimate claim."

Paleaobotanists have known for years that certain plant cells can last for millennia under the right conditions.

Some earlier claims of regeneration have not held up to scientific scrutiny, but the Yashina/Gilichinsky team was careful to use radiocarbon dating to ensure that the seeds and fruit found in the permafrost were not modern contaminants from S. Stenophylla, which still grows on the Siberian tundra.

Read more at Discovery News

Studying the Evolution of Life's Building Blocks

Studying the origin of life at its building blocks offers a unique perspective on evolution, says a researcher at Michigan State University.

Robert Root-Bernstein, MSU physiology professor, will answer the question of why a physiologist studies the origin of life at the annual meeting of the American Association for the Advancement of Science Feb. 16-20 in Vancouver, British Columbia.

Paleontologists study ancient life and reason that each species is a modification of the previous generation. Geneticists embrace this theory and trace the lineage of genes. Root-Bernstein wondered if there could be another level of paleontology embedded in the molecules that reflect evolution from the earliest stages of life and found in prebiotic chemistry, the study of chemical reactions that may have sparked the beginnings of life.

"By studying modules built from very simple chemicals, I'm hoping that it will lead to an understanding of a molecular paleontology in modern systems," he said. "Whether it's a human or a bacterium, we're all made from the same basic modules that have more than likely been around since the beginning of time."

For example, one aspect of Root-Bernstein's research is studying the small glucose binding sequences that occur in all protein and peptides like insulin. Focusing on these basic building blocks could provide new insights into diseases such as diabetes.

Having the characteristic of taking a nontraditional view has helped further Root-Bernstein's research.

"Albert Szent-Gyorgyi, the physiologist who discovered vitamin C, once defined discovery as seeing what everyone else sees and thinking what no one else thinks," he said. "I often find that phenomena that are obvious to other people are not obvious to me."

Root-Bernstein's ability to seek the common chemical building blocks between bacteria and humans formally known as molecular complementarity, is a distinctive view. This shared set of modules could be the basis for the evolution of the chemicals systems on which life is based, he added. It could, in fact, be the essential agent controlling evolution at every level.

Read more at Science Daily

NASA Spacecraft Reveals Recent Geological Activity On the Moon

New images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface. Scientists propose this geologic activity occurred less than 50 million years ago, which is considered recent compared to the moon's age of more than 4.5 billion years.

A team of researchers analyzing high-resolution images obtained by the Lunar Reconnaissance Orbiter Camera (LROC) show small, narrow trenches typically much longer than they are wide. This indicates the lunar crust is being pulled apart at these locations. These linear valleys, known as graben, form when the moon's crust stretches, breaks and drops down along two bounding faults. A handful of these graben systems have been found across the lunar surface.

"We think the moon is in a general state of global contraction because of cooling of a still hot interior," said Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum in Washington, and lead author of a paper on this research appearing in the March issue of the journal Nature Geoscience. "The graben tell us forces acting to shrink the moon were overcome in places by forces acting to pull it apart. This means the contractional forces shrinking the moon cannot be large, or the small graben might never form."

The weak contraction suggests that the moon, unlike the terrestrial planets, did not completely melt in the very early stages of its evolution. Rather, observations support an alternative view that only the moon's exterior initially melted forming an ocean of molten rock.

In August 2010, the team used LROC images to identify physical signs of contraction on the lunar surface, in the form of lobe-shaped cliffs known as lobate scarps. The scarps are evidence the moon shrank globally in the geologically recent past and might still be shrinking today. The team saw these scarps widely distributed across the moon and concluded it was shrinking as the interior slowly cooled.

Based on the size of the scarps, it is estimated that the distance between the moon's center and its surface shank by approximately 300 feet. The graben were an unexpected discovery and the images provide contradictory evidence that the regions of the lunar crust are also being pulled apart.

"This pulling apart tells us the moon is still active," said Richard Vondrak, LRO Project Scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "LRO gives us a detailed look at that process."

As the LRO mission progresses and coverage increases, scientists will have a better picture of how common these young graben are and what other types of tectonic features are nearby. The graben systems the team finds may help scientists refine the state of stress in the lunar crust.

"It was a big surprise when I spotted graben in the far side highlands," said co-author Mark Robinson of the School of Earth and Space Exploration at Arizona State University, principal investigator of LROC. "I immediately targeted the area for high-resolution stereo images so we could create a three-dimensional view of the graben. It's exciting when you discover something totally unexpected and only about half the lunar surface has been imaged in high resolution. There is much more of the moon to be explored."

Read more at Science Daily

High Definition Polarization Vision Discovered in Cuttlefish

Cuttlefish have the most acute polarization vision yet found in any animal, researchers at the University of Bristol have discovered by showing them movies on a modified LCD computer screen to test their eyesight.

Cuttlefish and their colourblind cousins, squid and octopus, see aspects of light -- including polarized light -- that are invisible to humans, giving them a covert communication channel. The Bristol study, published today in Current Biology found that cuttlefish were much more sensitive to polarization than previously thought.

Lead researcher Dr Shelby Temple from the Ecology of Vision Laboratory at the University of Bristol said: "Just like colour and intensity, polarization is an aspect of light that can provide animals with information about the world around them. If you've ever put on a pair of polarized sunglasses glasses to cut the glare from water or the road, or gone to a recent 3D movie, then you've observed some aspects of polarized light."

With collaborators at The University of Queensland, Brisbane, Australia, the team gave cuttlefish an eye exam; but instead of measuring their acuity they measured the smallest difference in the angle of polarization the cuttlefish could detect.

Since the team could not ask the cuttlefish what they could see, they took advantage of the chameleon-like colour changes that cuttlefish use for camouflage as a way of measuring whether the animals could detect the polarized stimuli.

"We modified LCD computer monitors to show changes in polarization instead of changes in colour, and then played videos of approaching objects and watched for changes in skin colour patterns to determine if the cuttlefish could see small changes in polarization contrast," said Dr Temple. "Cuttlefish change colour all the time and respond to the slightest movement so they are an excellent model.

"Cuttlefish were much more sensitive than we expected. It was previously thought that polarization sensitivity was limited to about 10-20 degree differences, but we found that cuttlefish could respond to differences as small as one degree."

In addition to measuring the limits of polarization vision in the cuttlefish, the team also modelled how underwater scenes might look to an animal that has such high-resolution polarization vision. Using colours instead of changes in polarization angle they created images of the polarized world that humans can see and showed that there is much more information available in the polarization dimension than was previously known.

Read more at Science Daily

Even Sharks Make Friends

Sharks have a reputation for being ruthless, solitary predators, but evidence is mounting that certain species enjoy complex social lives that include longstanding relationships and teamwork.

A new study, published in the latest Animal Behaviour, documents how one population of blacktip reef sharks is actually organized into four communities and two subcommunities. The research shows for the first time that adults of a reef-associated shark species form stable, long-term social bonds.

The image contrasts with usual reports on this species, which mistakenly sinks its sharp teeth into surfers and swimmers from time to time.

Lead author Johann Mourier told Discovery News that “other species, such as grey reef sharks and scalloped hammerheads form polarized groups where individuals have a specific place, and such species may also have complex social organization.”

Mourier, a scientist at the Center for Island Research and Environmental Study (CNRS-EPHE), and colleagues Julie Vercelloni and Serge Planes conducted the study at Moorea Island in the Society archipelago, French Polynesia. A total of seven sites were surveyed on a regular basis along just over 6 miles of the north shore of Moorea. The surveys included nearly hour-long dives at a depth close to 50 feet, with the diver photographing nearby sharks.

Analysis of the gathered data determined that the sharks were not within non-random collections, but rather had organized themselves into meaningful social groups.

“The four main communities are mixed-sex communities that use a specific home range, however, within these communities individuals tend to associate more often with others of the same sex and length,” Mourier said.

In a prior study, he determined that length is proportional to a shark’s age, with male blacktip reef sharks being mature at about the age of 7 and measuring around 3.6 feet long. Females are slightly larger than males.

Mourier suspects the sharks join together in communities for protection and to avoid aggression with each other. He and his colleagues also observed a remarkable feat, “when a group of about four or five blacktip reef sharks herded a school of fishes around a coral structure.” This suggests they can cooperate with each other to hunt as a team.

Yet another perk to organizing could be that each shark becomes a comforting landmark for others in the group. As Mourier said, “Using a home range and knowing all individuals may help individuals to have a better knowledge of their environment.”

The researchers point out that sharks’ relative brain mass-body ratios have been found to be comparable to those of mammals, indicating that they are capable of complex social behaviors on par with those demonstrated in birds and mammals.

It could just be that the highly mobile nature of sharks, combined with the difficulty of following individuals in the open sea, has kept their social interactions hidden away from human eyes until recent years.

In another study, led by Demian Chapman, researchers showed that lemon sharks at the Bimini islands, Bahamas, tended to stay near their coastal birthplace for many years.

"We were very surprised to see that many lemon sharks lingered for years around the island where they were born -- often more than half of their development to adulthood,” said Chapman, a shark scientist with the Institute for Ocean Conservation Science at Stony Brook University.

Read more at Discovery News

X-Rays Illuminate the Interior of the Moon

Unlike Earth, our Moon has no active volcanoes, and the traces of its past volcanic activity date from billions of years ago. This is surprising because recent Moonquake data suggest that there is plenty of liquid magma deep within the Moon and part of the rocks residing there are thought to be molten. Scientists have now identified a likely reason for this peaceful surface life: the hot, molten rock in the Moon's deep interior could be so dense that it is simply too heavy to rise to the surface like a bubble in water. For their experiments, the scientists produced microscopic copies of moon rock collected by the Apollo missions and melted them at the extremely high pressures and temperatures found inside the Moon. They then measured their densities with powerful X-ray beams.

The results are published in the Journal Nature Geoscience on 19 February 2012.

The team was led by Mirjam van Kan Parker and Wim van Westrenen from VU University Amsterdam and composed of scientists from the Universities of Paris 6/CNRS, Lyon 1/CNRS, Edinburgh, and the European Synchrotron Radiation Facility (ESRF) in Grenoble.

Five decades after the Apollo missions, the formation and geological history of the Moon still hold many secrets. The astronauts not only returned 380 kg of Moon rocks to Earth but also placed many scientific instruments on the lunar surface. Last year, NASA scientists published a new model for the make-up of the interior of the Moon, using Moonquake data from these Apollo-era seismometers. Renee Weber and her colleagues claim that the deepest parts of the lunar mantle, bordering on the small metallic core, are partially molten, by up to 30 per cent. In Earth, such bodies of magma tend to move towards the surface leading to volcanic eruptions. If the deep interior of the Moon contains so much magma, why don't we see spectacular volcanic eruptions at its surface?

The driving force for vertical movement of magma is the density difference between the magma and the surrounding solid material, making the liquid magma move slowly upwards like a bubble. The lighter the liquid magma is, the more violent the upward movement will be.

To determine the density of lunar magma, Wim van Westrenen and his colleagues synthesised moon rock in their laboratory in Amsterdam, using the composition derived from Apollo samples as their "recipe." The pressures and temperatures close to the core of the Moon are more than 45,000 bar and about 1500 degrees. It is possible to generate these extreme conditions with small samples, heating them with a high electric current while squashing them in a press. By measuring the attenuation of a powerful synchrotron X-ray beam at the ESRF traversing the sample both solid and molten, the density at high pressure and high temperature could be measured. "We had to use the most brilliant X-ray beam in the world for this experiment because the magma sample is so tiny and confined in a massive, highly absorbing container. Without a bright beam of X-rays, you cannot measure these density variations," says Mohamed Mezouar from the ESRF.

The measurements at the ESRF were combined with computer simulations to calculate the magma density at any location in the Moon.

Nearly all the lunar magmas were found to be less dense than their solid surroundings, similar to the situation on Earth. There is one important exception: small droplets of titanium-rich glass first found in Apollo 14 mission samples produce liquid magma as dense as the rocks found in the deepest parts of the lunar mantle today. This magma would not move towards the surface.

Read more at Science Daily

Babies Know What's Fair

"That's not fair!" It's a common playground complaint. But how early do children acquire this sense of fairness? Before they're 2, says a new study. "We found that 19- and 21-month-old infants have a general expectation of fairness, and they can apply it appropriately to different situations," says University of Illinois psychology graduate student Stephanie Sloane, who conducted the study with UI's Renée Baillargeon and David Premack of the University of Pennsylvania.

The findings appear in Psychological Science, a journal published by the Association for Psychological Science.

In each of two experiments, babies watched live scenarios unfold. In the first, 19-month-olds saw two giraffe puppets dance around at the back of a stage. An experimenter arrived with two toys on a tray and said, "I have toys!" "Yay!" said the giraffes. Then the experimenter gave one toy to each giraffe or both to one of them. The infants were timed gazing at the scene until they lost interest. Longer looking times indicated that something was odd -- unexpected -- to the baby. In this experiment, three-quarters of the infants looked longer when one giraffe got both toys.

In the second experiment, two women faced each other with a pile of small toys between them and an empty plastic box in front of each of them. An experimenter said, "Wow! Look at all these toys. It's time to clean them up." In one scenario, one woman dutifully put the toys away, while the other kept playing -- but the experimenter gave a reward to both the worker and the slacker. In another scenario, both women put the toys away and both got a reward. The observing 21-month-old infants looked reliably longer when the worker and the slacker were rewarded equally.

"We think children are born with a skeleton of general expectations about fairness," explains Sloane, "and these principles and concepts get shaped in different ways depending on the culture and the environment they're brought up in." Some cultures value sharing more than others, but the ideas that resources should be equally distributed and rewards allocated according to effort are innate and universal.

Other survival instincts can intervene. Self-interest is one, as is loyalty to the in-group -- your family, your tribe, your team. It's much harder to abide by that abstract sense of fairness when you want all the cookies -- or your team is hungry. That's why children need reminders to share and practice in the discipline of doing the right thing in spite of their desires.

Still, says Sloane, "helping children behave more morally may not be as hard as it would be if they didn't have that skeleton of expectations."

Read more at Science Daily