Caterpillars evolved from onychophorans by hybridogenesis
1. Donald I. Williamson (1)
- Author Affiliations
1. Marine Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
Abstract:
I reject the Darwinian assumption that larvae and their adults evolved from a single common ancestor. Rather I posit that, in animals that metamorphose, the basic types of larvae originated as adults of different lineages, i.e., larvae were transferred when, through hybridization, their genomes were acquired by distantly related animals. “Caterpillars,” the name for eruciforms with thoracic and abdominal legs, are larvae of lepidopterans, hymenopterans, and mecopterans (scorpionflies). Grubs and maggots, including the larvae of beetles, bees, and flies, evolved from caterpillars by loss of legs. Caterpillar larval organs are dismantled and reconstructed in the pupal phase. Such indirect developmental patterns (metamorphoses) did not originate solely by accumulation of random mutations followed by natural selection; rather they are fully consistent with my concept of evolution by hybridogenesis. Members of the phylum Onychophora (velvet worms) are proposed as the evolutionary source of caterpillars and their grub or maggot descendants. I present a molecular biological research proposal to test my thesis. By my hypothesis 2 recognizable sets of genes are detectable in the genomes of all insects with caterpillar grub- or maggot-like larvae: (i) onychophoran genes that code for proteins determining larval morphology/physiology and (ii) sequentially expressed insect genes that code for adult proteins. The genomes of insects and other animals that, by contrast, entirely lack larvae comprise recognizable sets of genes from single animal common ancestors.
Astronomers from China and the United States may cooperate on building the world's largest telescope aimed at providing deeper insight into the very early stages of the universe, Xinhua news agency reported on Friday.
The Thirty-Meter-Telescope (TMT), conceived and headed by the University of California and the California Institute of Technology (Caltech), is expected to be completed in 2019, the official Chinese news agency said.
"It is a big undertaking and it will define the future of astronomy and astrophysics for about 60 or 70 years, so it will automatically involve a large international community," said Caltech President Jean-Lou Chameau in an interview with Xinhua.
Xinhua said the university and Caltech are talking to Chinese astronomers and scientists about cooperation on funding and technology, although no final decision has been made.
Canada and Japan have signed up to the project, which needs total financing of $1 billion, it said.
The telescope, with a mirror 30 meters in diameter, will have the sharpest view possible of the universe and will pick up images of galaxies and stars forming 13 billion light years away. It will be located on top of Mauna Kea, Hawaii.
Look! Titan has fog at the south pole! All of those bright sparkly reddish white patches are fog banks hanging out at the surface in Titan's late southern summer.
I first realized this a year ago, but it took me until now to finally have the time to be able to put all of the pieces together into a scientific paper that is convincing enough that I can now go up to any person in the street and say: Titan has fog at the south pole!
I will admit that the average person in the street is likely to say hmph. Or yawn. Or ask where Titan is. So let me tell you why finding fog at the south pole of Titan has been the scientific highlight of my summer.
Titan is the only place in the solar system other than the earth that appears to have large quantities of liquid sitting on the surface. At both the north and south poles we see large lakes of something dark. Oddly, though, we don’t actually know what that dark stuff is. At least some of it must certainly be ethane (that’s C2H6, for all of you who have forgotten your high school chemistry). Ethane slowly drips out of the sky on Titan, sort of like soot after a fire, only liquid soot in this case. Over geological time, big ponds of ethane could accumulate into the things that look like lakes on Titan. Odd as they sound, big lakes of liquid ethane are, at least to me, the least interesting possibility. They are the least interesting because ethane is a one way street. Once the liquid ethane is on the ground, it can’t evaporate and is there pretty much forever, unless it somehow sinks into the interior.
Why does all of that ethane drip out of the sky? Because sunlight breaks down methane (CH4) to form ethane much the same way it breaks down car exhaust fumes to form smog in big cities. There’s plenty of methane in the atmosphere, so the supply of ethane is near endless. The dripping will not end soon.
But the methane is where all of the potential action is. Methane is to Titan what water is to the earth. It’s a common component in the atmosphere and, at the temperature of Titan, it can exist in solid, liquid, or gas form. Like water on the earth, it forms clouds in the sky. Like water on the earth, it probably even forms rain. But what we don’t know is whether or not that rain makes it to the surface and pools into ponds or streams or lakes which then evaporate back into the atmosphere to start the cycle over again. In short, we don’t know if Titan has an active methane atmosphere-surface hydrological cycle analogous to the water atmosphere-surface hydrological cycle on the earth.
Until now.
Because there is fog.
Cretaceous oceanic anoxic event 2 triggered by a massive magmatic episode
Steven C. Turgeon (1) & Robert A. Creaser(1)
1. Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T2G 2E3, Canada
Correspondence to: Steven C. Turgeon1 Correspondence and requests for materials should be addressed to S.C.T. (Email: turgeonsc@ualberta.ca).
Nature 454, 323-326 (17 July 2008) | doi:10.1038/nature07076; Received 3 October 2007; Accepted 1 May 2008
Abstract:
Oceanic anoxic events (OAEs) were episodes of widespread marine anoxia during which large amounts of organic carbon were buried on the ocean floor under oxygen-deficient bottom waters1, 2. OAE2, occurring at the Cenomanian/Turonian boundary (about 93.5 Myr ago)3, is the most widespread and best defined OAE of the mid-Cretaceous. Although the enhanced burial of organic matter can be explained either through increased primary productivity or enhanced preservation scenarios1, 2, the actual trigger mechanism, corresponding closely to the onset of these episodes of increased carbon sequestration, has not been clearly identified. It has been postulated that large-scale magmatic activity initially triggered OAE2 (refs 4, 5), but a direct proxy of magmatism preserved in the sedimentary record coinciding closely with the onset of OAE2 has not yet been found. Here we report seawater osmium isotope ratios in organic-rich sediments from two distant sites. We find that at both study sites the marine osmium isotope record changes abruptly just at or before the onset of OAE2. Using a simple two-component mixing equation, we calculate that over 97 per cent of the total osmium content in contemporaneous seawater at both sites is magmatic in origin, a approx30–50-fold increase relative to pre-OAE conditions. Furthermore, the magmatic osmium isotope signal appears slightly before the OAE2—as indicated by carbon isotope ratios—suggesting a time-lag of up to approx23 kyr between magmatism and the onset of significant organic carbon burial, which may reflect the reaction time of the global ocean system. Our marine osmium isotope data are indicative of a widespread magmatic pulse at the onset of OAE2, which may have triggered the subsequent deposition of large amounts of organic matter.
ust as the 1986 Chernobyl nuclear accident convinced many Ukrainians that they did not want to remain part of the Soviet Union, so too, despite all the differences in the extent of the disaster, the Sayan-Shushen dam accident is leading many Siberians to conclude the same thing about remaining part of the Russian Federation.
[...]
Many in Moscow and elsewhere continue to comfort themselves with the notion that it is wrong to draw any parallels between the impact of Chernobyl on Ukrainians and the impact of Sayan-Shushen on Siberians. After all, they say, Siberia has “nowhere to go.” But that is not quite the case, Tarasov suggests.
“Under Gorbachev and Yeltsin, only a politician who did not need public support could fail to speak about the necessity of decolonizing [that region with its immense natural resources] and the establishment of a Siberian (Eastern Siberian, Central Siberian and Yenisey) Republic” as a goal of Russian policy.
Under Putin, however, no one remembered “Siberian separatism” because Moscow had “buried the theme of regional patriotism.” And efforts by the supporters of that idea seldom found much support. But if a problem is not discussed, Tarasov says, “it does not disappear. It simply goes into the underground.”
The Sayan-Shushen dam disaster and even more the way Moscow has mishandled it and the media have discussed it suggest that Siberian separatism may be about to re-emerge and challenge not only the relationship between Putin and the oligarchs but also that between “the colony” of Siberia and the imperial center.
An international team of researchers has debunked one of astronomy's long held beliefs about how stars are formed, using a set of galaxies found with CSIRO's Parkes radio telescope.
When a cloud of interstellar gas collapses to form stars, the stars range from massive to minute.
Since the 1950s astronomers have thought that in a family of new-born stars the ratio of massive stars to lighter ones was always pretty much the same — for instance, that for every star 20 times more massive than the Sun or larger, you'd get 500 stars the mass of the Sun or less.
"This was a really useful idea. Unfortunately it seems not to be true," said team research leader Dr Gerhardt Meurer of Johns Hopkins University in Baltimore.
The different numbers of stars of different masses at birth is called the 'initial mass function' (IMF).
Most of the light we see from galaxies comes from the highest mass stars, while the total mass in stars is dominated by the lower mass stars.
By measuring the amount of light from a population of stars, and making some corrections for the stars' ages, astronomers can use the IMF to estimate the total mass of that population of stars.
Results for different galaxies can be compared only if the IMF is the same everywhere, but Dr Meurer's team has shown that this ratio of high-mass to low-mass newborn stars differs between galaxies.
For instance, small 'dwarf' galaxies form many more low-mass stars than expected.
After years spent hunting for the buried remains of prehistoric animals, a Canadian paleontologist now plans to manipulate chicken embryos to show he can create a dinosaur.
Hans Larsson, the Canada Research Chair in Macro Evolution at Montreal's McGill University, said he aims to develop dinosaur traits that disappeared millions of years ago in birds.
Larsson believes by flipping certain genetic levers during a chicken embryo's development, he can reproduce the dinosaur anatomy, he told AFP in an interview.
Though still in its infancy, the research could eventually lead to hatching live prehistoric animals, but Larsson said there are no plans for that now, for ethical and practical reasons -- a dinosaur hatchery is "too large an enterprise."
"It's a demonstration of evolution," said Larsson, who has studied bird evolution for the last 10 years.
"If I can demonstrate clearly that the potential for dinosaur anatomical development exists in birds, then it again proves that birds are direct descendants of dinosaurs."
The research is funded by the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs program and National Geographic.
Africa will seek billions in compensation from industrialised nations during key climate change talks in Copenhagen later this year, an official said Monday.
Representatives from eight countries that make up a panel of leaders chosen to represent the continent in Denmark met here to thrash out the details of a common stance for the December meeting.
"The proposition is that it has to be an amount significant enough to lead to rapid, sustainable development and industrialisation of developing countries, in particular Africa," Lumumba Di-Aping, Sudan's deputy UN representative, told AFP after the meeting.
He said the compensation sought would amount to billions of dollars and "could be anything up to five percent of the global GDP," which would be equivalent to around three trillion dollars.
He added that a final decision would be made by African leaders during a "special heads of state summit" in Libya on Saturday.
Rhoda Tumusime, the AU's commissioner for rural economy and agriculture, said Ethiopia, whose Prime Minister Meles Zenawi championed the continent's climate change concerns at the recent G8 Summit, is likely to be chosen as "representative" in the Libya meeting.
"Ethiopia would be ideal to be the spokesperson of the continent. It is being suggested because its leader understands the issue of climate change," she said.
According to statistics from the UN Environment Programme, between 75 million and 250 million people in Africa may face water shortages by 2020.
It also estimates that up to 50 billion dollars would be needed every year to cope with the effects of climate change in Africa.
"Unfortunately, unlike the later events, which are based on data from stratal and fossil evidence, this first Medean event is no more than an educated guess. Many of us believe it to be true, although since ther is currently no way to scientifically test this hypothesis, it must remain an educated guess, and no more.pgs 72 -73.
"Over the past several years, biochemists conducting experiments to find possible alternatives to our familiar Earth life have attempted and in some cases have succeeded, in producing DNA with exotic "languages," obtained by changing the number of nucleaotides used to code for a specific amino acid. Thus it is possible - indeed, I believe likely - that early DNA life on Earth might have come in a vaierty of forms, perhaps all slightly different from our now familiar DNA. If so, it is probable separate kinds of DNA competed against each other. [...] [I]t is probable that there would have been intense competition betweene ach of the kinds of DNA, competition that would have been inherently Darwinian. The suppression of other kinds of life would have followed, and if so, this would have been a Medean Event, in fact, the first example of a Medean event: the takeover of a single kind of life. Elsewhere I have followed other evolutionary biologists in supposing that the highest diversity of life, the most basic kinds of life, not species was surely early in Earth's history. "
"The methane atmosphere hypothesized to have been present on the early Earth may have been a byproduct of the first life, a waste product of its metabolism. Life was present as a series of oil-like slicks and stacked bacterial layers and sediments, called stromatolites. Although individually small in size, these microbes became globally abundant and in so doing began to change the planet. This is the conclusion of the eminent atmospheric scientist and astrobiologist James Kasting of Penn State. His new work describes how the formation of methane-producing life on Earth nearly ended the saga of life on our planet in its earliest epochs by creating a cold buffer on the surface of the planet. The formation of the methane haze took an already cold world (the Sun was more than 30 percent less energetic) and added a layer of clouds for the first time that reflected heat back into space. But for the very high volcanic heat flow on our planet, this type of condition made the planet much worse for life's survival. [...] In any event, this by-product of cooling clouds is not the predicted course of events under the Gaia hypothesis. This is the first test that shows how earliest life nearly ended its own history through its formation."
"Oxygen caused a massive mass extinction on planet Earth: the biovolume of life on the planet plummeted. This is a Medean result. Only the children of the bugs that could tolerate oxygen - and the cyanobacteria that learned to make it, and the bugs that later learned to breath it - would thereafter enoy the sunlight."Pg 75
pgs 79-80.
The rise of animals that so spectacularly ocured during the 540-500 million year-old "Cambrian Explosion" is deemed one of the great evolutionary events ever to have affected the Earth. Clearly the number of species on the planet radically increased. But what of the biomass? Just the opposite seems to have occured. Concomitant with the rise of animals and higher plants, there is a drastic reduction in the number of stromalites and other evidence of layered bacterial slicks. The evolution of herbivores and carnivores among the emergent animals was a major reasons for this. The fecal pellets of the newly evolved zooplankton - little animals that feed on plankton and other microorganisms - stuck together and formed slime balls that readily sank down to the abyssal depths, removing organic carbon and nutrients from being recycled by way of photosynthesis. Thus, we can view the evolution of complex life on our planet as Medean since it led to a reduction in the total biomass.
This biomass reduction was probably caused not only by herbivorous success of the newly evolved animals. There may have been a significant drop in global temperature as well - in fact the largest single drop in planetary temperature in Earth history, if the modeled results are correct.
By the end of the Cretaceous there were planet-spanning forests. One effect of the [Chicxulub Impact] was the ignition of continent spanning forest fires. This produced an enmorous amount of ash that filled up the atmosphere. This soot, a product of life, caused global cooling for some months after the impact, which seems to have played a significant role in the kill mechanism. Again, a Medean Effect.
Reassessing the Source of Long-Period Comets
Nathan A. Kaib (1)(*)
Thomas Quinn (1)
1 Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195–1580, USA.
* To whom correspondence should be addressed.
Nathan A. Kaib , E-mail: kaib@astro.washington.edu
We present numerical simulations to model the production of observable long-period comets (LPCs) from the Oort Cloud, a vast reservoir of icy bodies surrounding the Sun. We show that inner Oort Cloud objects can penetrate Jupiter's orbit via a largely unexplored dynamical pathway, and they are a significant, if not the dominant, source of known LPCs. We use this LPC production to place observationally motivated constraints on the population and mass of the inner Oort Cloud, which are consistent with giant planet formation theory. These constraints indicate that only one comet shower producing late Eocene bombardment levels has likely occurred since the Cambrian Explosion, making these phenomena an improbable cause of additional extinction events.
Russia's first fifth-generation fighter jet will make its maiden flight by year-end, the aircraft's designer said, as Moscow seeks to catch up with the United States in a military aviation dogfight.
Military and civilian plane-maker Sukhoi is bidding to revive an industry crippled by the 1991 collapse of the Soviet Union, which left Western rivals to dominate passenger markets and Washington to launch a fifth-generation fighter.
Asked when Russia's first post-Soviet fighter jet would take off, Sukhoi General Director Mikhail Pogosyan told Reuters: "We will spare no effort for this to happen this year, and I believe we have every reason to say this work is proceeding according to plan."
Pogosyan also predicted Sukhoi would take up to 20 percent of the world's regional jet market with Russia's first passenger airliner in almost two decades, the Superjet 100.
"We expect that, in our segment of regional passenger airliners, we'll take a 15-20 percent share of the global market. We think it will take us five to 10 years to achieve this," he said.
In the Reuters television interview on the sidelines of the MAKS-2009 aerospace fair outside Moscow on Wednesday, Pogosyan said he was hopeful Sukhoi's fifth-generation fighter jet would not face any last-minute hitches.
"There are always 'nuances' in the creation of military equipment that are impossible to predict," he said. "But I am hopeful we will be able to avoid such nuances."
Fifth-generation jets, such as the U.S. F-22 Raptor stealth fighter which first flew in 1997, are invisible to radar and boast "intelligent" on-board flight and arms control systems and supersonic cruising speeds.
Asked if the Russian fighter could challenge the U.S. Raptor, Pogosyan said he had no reason to doubt that the Sukhoi plane would be competitive.
Konstantin Makiyenko, deputy head of the Moscow-based Centre for Analysis of Strategies and Technologies (CAST) think tank, said that, even with delays, the Russian plane would likely make its first flight by January or February.
"But this doesn't matter much," he said. "There could be at least 10 years between the first flight of the fifth-generation prototype and commercial production."
At the bottom of the Arctic Sea lie vast deposits of methane gas trapped in frozen, icy forms called methane hydrates, and climate scientists would very much prefer that it remains trapped down there. Methane is a powerful greenhouse gas, and some researchers worry that a warming ocean may melt the icy structures, allowing the gas to travel up through the water to the atmosphere, where it could further contribute to global warming. Now, scientists who have been scanning the seas for signs of trouble say they may have found some.
The researchers spotted 250 plumes of methane gas bubbling up through the sea north of Norway. The region where the team found the plumes is being warmed by the West Spitsbergen current, which has warmed by 1 °C over the past 30 years. “Hydrates are stable only within a particular range of temperatures,” says [study coauthor Tim] Minshull. “So if the ocean warms, some of the hydrates will break down and release their methane” [New Scientist]. However, the scientists couldn’t prove that the methane is being released as a direct result of the warming, and say it’s possible there have always been methane seeps like these.
The plumes, reported in the journal Geophysical Research Letters, were detected using a kind of sonar that is typically used by biologists searching for shoals of fish. All of the gas plumes spotted by the researchers dissolved into the water before reaching the ocean’s surface, meaning that bubbles of methane weren’t escaping into the atmosphere to contribute to global warming. Just because it fails to reach the surface doesn’t mean the methane is harmless, though, as some of it gets converted to carbon dioxide. The CO2 then dissolves in seawater and makes the oceans more acidic [New Scientist]
Russian President Dmitry Medvedev thinks his country's supercomputing capabilities need a jump-start. In an address to Russia's Security Council in late July, Medvedev chided his fellow bureaucrats that the country has failed to invest in supercomputing or grid technologies, putting the nation's security and industrial competitiveness at risk. His speech began by laying out the case for these technologies:It's no secret that the majority of the most developed and advanced nations are focusing on this. It is obvious that the large-scale use of high technology data processing increases the effects of research many times over, radically reduces the cost of designing the most advanced and complex types of products, naturally increases the quality of industrial products, and streamlines business processes. It is precisely for these reasons that the entire world is working on this. Any country that makes headway in relation to creating supercomputers has, of course, advantages in terms of competitiveness, increasing its defence capacities, and strengthening security.
Medvedev went on to complain that Russia ranks only 15th in the aggregate capacity of its supercomputers, noting that "476 out of the 500 supercomputing systems use computers manufactured in the United States of America." Although he didn't mention it, Russia's top system, a 71.3 teraflop (Linpack) HP machine at the Joint Supercomputing Center in Moscow, has less than 7 percent the Linpack performance of the top system in the world, IBM's Roadrunner supercomputer. Even the top 50 systems of the CIS states (the former Soviet Republics) currently have an aggregate Linpack performance of just 382 teraflops, or about one third the power of the single Roadrunner machine. Considering that Russia's 2008 GDP of $2.225 trillion (according to the CIA World Factbook) places it 8th in the world, the country is definitely underachieving in the HPC realm.
A 109 million year-old rock containing 15 fossilized footprints of dinosaurs has been discovered in a village near Zarand, Kerman province of Iran.
Experts say the unique collection of footprints may belong to a mother dinosaur and her young, Mehr News Agency reported.
Mine workers in southwestern Indiana have unearthed the tusks and skeletal remains of a prehistoric elephant that lived more than 12,000 years ago.
The workers were digging a coal slurry storage pit recently at Vectren's Black Panther Mine about 30 miles south of Terre Haute when they noticed the fossil mastodon bones in a backhoe shovel.
After realizing the importance of the find, the crew notified the Indiana Division of Reclamation, which regulates mining operations.
Division of Reclamation archaeologist Tim Wright praised the workers for saving the fossils of the prehistoric elephant and contacting the state.
"It's just an accident they ran into it and they did the right thing by notifying us," Wright said.
He said the bones include pieces of ribs, skull, tusks and a kneecap. The fossilized remains have been turned over to the Indiana State Museum for further study and preservation.
Wright said Vectren has set aside the dirt in which the fossils were found. Paleontologists from the state museum have conducted more searches for additional remains.
[...]
Last month, a couple in central Michigan found the bones of a 10,000-plus-year-old mastodon. Rich and Annette Schneider planned to put a pond in their backyard in Portland, Mich. and the dig turned up bones including a leg, a rib and a tusk.
The European Space Agency (ESA) on Wednesday signed a deal with its Russian counterpart Roscosmos to cooperate on two Mars exploration projects, Russia's Interfax news agency reported.
[...]
Under the deal, the ESA will use Russia's Proton rocket as part of its Exomars project to send a robotic rover to the Mars surface and buy Russian parts for the rover's power supply system.
The deal will also see Russia's Phobos-Grunt project -- to send a probe to Mars' Phobos moon in October 2009 -- use the ESA's terrestrial communication facilities during its mission.
Research at Virginia Tech has shown that the oldest complex life forms -- living in nutrient-rich oceans more than 540 million years ago – likely fed by osmosis.
The researchers studied two groups of modular Ediacara organisms, the fern-shaped rangeomorphs and the air mattress-shaped erniettomorphs. These macroscopic organisms, typically several inches in size, absorbed nutrients through their outer membrane, much like modern microscopic bacteria, according to the cover story of the Aug. 25, 2009 issue of the Proceedings of the National Academy of Sciences (PNAS), "Osmotrophy in modular Edicara organisms," by Marc Laflamme, Shuhai Xiao, and Michal Kowalewski. Laflamme, now a Postdoctoral Fellow in the Department of Geology and Geophysics at Yale University, did the research as a postdoc in Xiao's lab at Virginia Tech. Xiao and Kowalewski are professors of geobiology in the College of Science at Virginia Tech.
The rangeomorphs had a repeatedly branching system like fern leaves and the erniettomorphs had a folded surface like an inflated air mattress to make tubular modules. "These organisms are unlike any life forms since and so are poorly understood," said Laflamme.
Their feeding strategy has been a topic of controversy, with theories ranging from parasitism to symbiosis to photosynthesis. "Some hypotheses can be ruled out because the organisms lack feeding structures, such as tentacles or mouths, and because many of them lived in the deep ocean where there was no sunlight for photosynthesis" said Xiao.
The researchers decided to simulate various morphological changes in the overall construction of the organisms to test whether it would have been possible for them to attain surface area to volume ratios on the same order as modern bacteria that feed by osmosis. Theoretical models were constructed to explore the effects of length, width, thickness, number of modules, and presence of internal vacuoles, on the surface area of the Precambrian fossils. "Modeling efforts suggest that internal vacuoles – that is, voids filled with fluids or other biologically inert materials – are a particularly effective way of increasing surface-to-volume ratio of complex, macroscopic organisms," said Kowalewski.
They discovered that the two groups (the repeatedly branching rangeomorphs and the air-mattress like erniettomorphs) grew and constructed their bodies in different ways; however both groups attempted to maximize their surface-area to volume ratios in their own way. "The increase in size was clearly accomplished primarily by addition of modules for the erniettomorphs and repetitive branching and inflation of modules for the rangemorphs," Laflamme said. "The repeated branching system in rangeomorphs was essential to allow for a high surface-area to volume ratio necessary for proper osmosis-based feeding."
Today, only microscopic bacteria find it efficient to us only osmosis to feed, although some animals, such as sponges and corals, use osmosis as a supplementary food source. But in the Ediacaran period, 635 to 541 million years ago, with nutrient-rich oceans, "a diffusion-based feeding strategy was more feasible," Laflamme said.
"We believe the Ediacarans were feeding on dissolved organic carbon, which can come in many forms," he said. "It represents the organic material originating from plants, fungi, animals -- you name it, which has dissolved into fats and proteins during natural organic decay. There is a growing body of evidence that in Ediacaran times, due mainly to the absence of animals with true guts capable of packaging organic matter into fecal pellets, there was a much greater pool of dissolved organic nutrients, especially in deeper waters. Without fecal pellets, organic substances would have remained in suspension and decomposed into fats and proteins capable of dissolution into marine waters," he said. "We believe these compounds were then absorbed via osmosis through Ediacaran "skin" due to the high surface-area to volume ratios."
Osmotrophy in modular Ediacara organisms
1. Marc Laflamme (1)
2. Shuhai Xiao
3. Michał Kowalewski
Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
1. To whom correspondence should be sent at the present address: Department of Geology and Geophysics, Yale University, P.O. Box 208109, New Haven, CT 06520-8190. E-mail: marc.laflamme@yale.edu
Abstract:
The Ediacara biota include macroscopic, morphologically complex soft-bodied organisms that appear globally in the late Ediacaran Period (575–542 Ma). The physiology, feeding strategies, and functional morphology of the modular Ediacara organisms (rangeomorphs and erniettomorphs) remain debated but are critical for understanding their ecology and phylogeny. Their modular construction triggered numerous hypotheses concerning their likely feeding strategies, ranging from micro-to-macrophagus feeding to photoautotrophy to osmotrophy. Macrophagus feeding in rangeomorphs and erniettomorphs is inconsistent with their lack of oral openings, and photoautotrophy in rangeomorphs is contradicted by their habitats below the photic zone. Here, we combine theoretical models and empirical data to evaluate the feasibility of osmotrophy, which requires high surface area to volume (SA/V) ratios, as a primary feeding strategy of rangeomorphs and erniettomorphs. Although exclusively osmotrophic feeding in modern ecosystems is restricted to microscopic bacteria, this study suggests that (i) fractal branching of rangeomorph modules resulted in SA/V ratios comparable to those observed in modern osmotrophic bacteria, and (ii) rangeomorphs, and particularly erniettomorphs, could have achieved osmotrophic SA/V ratios similar to bacteria, provided their bodies included metabolically inert material. Thus, specific morphological adaptations observed in rangeomorphs and erniettomorphs may have represented strategies for overcoming physiological constraints that typically make osmotrophy prohibitive for macroscopic life forms. These results support the viability of osmotrophic feeding in rangeomorphs and erniettomorphs, help explain their taphonomic peculiarities, and point to the possible importance of earliest macroorganisms for cycling dissolved organic carbon that may have been present in abundance during Ediacaran times.
The University of California will have to shelve plans for a $113 million computer research center in the hills above the Berkeley campus until a federal agency studies possible damage to Strawberry Canyon, a federal judge has ruled.
U.S. District Judge William Alsup of San Francisco issued an injunction in March prohibiting construction of the center, the possible new home of U.S. Department of Energy supercomputers, until he rules on whether a new environmental study is needed.
On Monday, Alsup said the project would be funded and controlled by the federal government and therefore is covered by federal law, which requires a government study of potential environmental harm before construction.
Although the federal government has not committed to paying for the computer center, Alsup said UC expects it to do so. He also said the Energy Department paid the salaries of employees at the Lawrence Berkeley National Laboratory - including its then-director, Steven Chu, now the U.S. energy secretary - who influenced the project's scope and budget.
Both UC and the federal agency had argued that the center, which the university would own, would be a state project. The university conducted an environmental study under California law last year and decided that constructing the building would not harm the hillside, a conclusion that opponents questioned.
Construction had been scheduled to start in March. The judge has quoted project officials as saying a further environmental report would cause a year's delay.
The proposed Computational Research and Theory Facility, a joint project of the university and the UC-operated Lawrence Berkeley laboratory, is to be built on lab property near Strawberry Canyon.
The 126,000-square-foot building would house high-performance Energy Department computers now located in a leased building in Oakland that is running out of space. It would be used by researchers and students from both the university and Lawrence Berkeley.
A group called Save Strawberry Canyon sued in July 2008, saying construction in a steep area prone to fires and virtually atop the Hayward Fault was risky. The group said the university could move at least some of the computer equipment to industrially zoned land it owns in Richmond.
China will start cutting its carbon emissions by 2050, its top climate change policymaker was quoted as saying in the Financial Times Saturday, the first time the nation has given a timeframe.
"China?s emissions will not continue to rise beyond 2050," said Su Wei, director general of the National Development and Reform Commission's climate change department, according to the paper.
The thinning of a gigantic glacier in Antarctica is accelerating, scientists warned today.
The Pine Island Glacier in West Antarctica, which is around twice the size of Scotland, is losing ice four times as fast as it was a decade years ago.
The research, published in the journal Geophysical Research Letters, also reveals that ice thinning is now occurring much further inland. At this rate scientists estimate that the main section of the glacier will have disappeared in just 100 years, six times sooner than was previously thought.
The Pine Island Glacier is located within the most inaccessible area of Antarctica – over 1000 km from the nearest research base – and was for many years overlooked. Now, scientists have been able to track the glacier's development using continuous satellite measurements over the past 15years.
"Accelerated thinning of the Pine Island Glacier represents perhaps the greatest imbalance in the cryosphere today, and yet we would not have known about it if it weren't for a succession of satellite instruments," says Professor Andrew Shepherd, a co-author of the research from the School of Earth and Environment at the University of Leeds.
"Being able to assemble a continuous record of measurements over the past 15 years has provided us with the remarkable ability to identify both subtle and dramatic changes in ice that were previously hidden," he adds.
Scientists believe that the retreat of glaciers in this sector of Antarctica is caused by warming of the surrounding oceans, though it is too early to link such a trend to global warming.
The 5,400 km squared region of the Pine Island Glacier affected today is big enough to impact the rate at which sea level rise around the world.
"Because the Pine Island Glacier contains enough ice to almost double the IPCC's best estimate of 21st century sea level rise, the manner in which the glacier will respond to the accelerated thinning is a matter of great concern " says Professor Shepherd.
At one time or another most of us wonder where we came from, where our parents or grandparents and their parents came from. Did our ancestors come from Europe or Asia? As curious as we are about our ancestors, for practical purposes, we need to think about the ancestry of our genes, according to Cecil Lewis, assistant professor of anthropology at the University of Oklahoma. Lewis says our genetic ancestry influences the genetic traits that predispose us to risk or resistance to disease.
Lewis studies genetic variation in populations to learn about the peopling of the Americas, but his studies also have an impact on genetic-related disease research. Some 15,000-18,000 years ago, people came from Asia through the Bering Strait and began to fill the American continents. The Americas were the last continents to be populated, so Lewis wants to understand how this process happened. His recent study focuses on South America and asks what part of the subcontinent has the most genetic diversity.
A complete understanding of this research depends on a very important population genetic process called the "founder effect." The geographic region with the most genetic diversity is characteristic of the initial or "parent" population. For example, a group of people leave a parent population and become founders of a new daughter population in an uninhabited geographic region. They typically take with them only a small set of the parent population's genetic diversity. This is called a founder effect.
The world pattern of founder effects in human populations begins in Africa. The genetic diversity in the Middle East is largely a subset of the genetic diversity in Africa. Similarly, the genetic diversity in Europe and Asia is largely a subset of the genetic diversity in Africa and the Middle East. The genetic diversity of the Americas is largely a subset of that in Asia. As a result, DNA tells a story about human origins, which began in Africa and spread throughout the world
Lewis is interested in the founder effects within the Americas with a particular focus on South America. At the outset, Lewis expected western South America to have a more diverse population than eastern South America because most anthropologists believe South America to have been peopled from west to east. Unexpectedly, the genetic data from the Lewis study was not consistent with this idea.
In this new study, Lewis looked at more than 600 independent genetic markers called short-tandem repeats. These markers were dispersed throughout the human genome. They were initially published by Lewis and his colleagues in large scale collaboration; the dataset is the largest survey of Native American genetic diversity today. Surprisingly, genetic analysis of these data estimated more genetic diversity in eastern than western South America. This was not the first time Lewis observed this pattern.
Lewis first observed this pattern in 2007 with his post-doctoral advisor using a more limited genetic dataset. The fact that the new genome-wide dataset provided a similar result was surprising; this result questions the most widely accepted scenario for the peopling of South America. While the focus of this study was South America, a similar and interesting pattern of genetic diversity emerged in North America. The pattern suggests another major founder effect in North America, but after the initial founder effect from Asia.
1. Life is NOT a part of a self correcting or self regulating system. Life is actually suicidal and that life's interactions with the environment mostly, by and large, make it less friendly for life's continued existence.So if these are the basic characteristics, boiled down and as interpreted by me, what are the feedbacks that life is producing to make things worse for itself. The main feedback cycle that is on Ward's mind is the carbon cycle and global warming. With his experience with the Permian Extinction, the writing of Under the Green Sky and his upcoming book The Flooded Earth, global climate change looms large on Ward's mind these days. It is Ward's hypothesis that positive feedback cycles predominate the carbon cycle. Here are the ones he lists:
2. Diversity of life is completely divorced from the total biomass. In fact, a lot of what Ward seems to argue is that the more diverse life is, the less biomass there is. Over time, the total biomass is decreasing due to life using up its available resources and as a consequence (or so I am interpreting his writing) the diversity increases as life must find new ways of exploiting what's left.
3. Every time a 'breakthrough' takes place for life in either exploiting some new energy source or some new way of organizing itself, there's an initial BOOM of biomass and then a drop off with a steady decline over time following.
4. Resource plundering/competitive poisoning (hyper-darwinism?). This one wasn't mentioned earlier because it wasn't with the standard definition section of what Medean Life was supposed to be. All life takes, hoards, plunders resources to the detriment of all others and often poisons everything else around it to further its advantage. The anaerobic bacteria that produces hydrogen sulfide is a good example. The black walnut or eucalyptus is another pair. Humanity is the pinnacle of this, but not an exception like is normally portrayed. Oceanic eutrophication (hypoxia/anoxia of the lower depths) is another example according to Ward, although, he breaks it out into its own category, it really is just another example of plunder/poisoning.
1. Increased atmospheric carbon dioxide increases photosynthesis. This increases carbon sequestration (negative feedback, CO2 goes up, amount of CO2 sequestered corrects for this, at least somewhat)
2. Increased temperature (from increased CO2) leads to increased soil respiration, which moves a lot of the organic carbon in the soil into the atmosphere (positive feedback, warmer leads to more carbon coming from soil, which leads to warmer still)
3. Warmer temperatures increase fire frequency, which replaces older trees with younger ones, which in turn releases more carbon into the atmosphere (another positive feedback)
4. Warming may lead to drying, which will cause greater desertification which will in turn cause sparser vegetation which will increase dust clouds and over all planetary albedo, causing cooling (negative feedback)
5. Higher atmospheric carbon may cause increased selection for drought resistant vegetation which will cause more intrusions of shrub and other dry climate resistant plants intruding into desert regions which will decrease albedo and dust clouds (positive feedback)
6. Warming leads to tundra being replaced by boreal forest. This decreases planetary albedo (positive feedback)
7. Warming soil produces more methane than cooler soil. As the world warms, the soil produces more which warms the earth more. (positive feedback)
8. Warming soil increases the production of Nitrous oxide (positive feedback)
9. Warming polar regions cause release of methane and carbon dioxide buried in the peatlands, etc. (positive feedback)
Taking advantage of advanced techniques to correct distortions caused by Earth's atmosphere, astronomers used the NSF-supported Gemini Observatory to capture the first images of clouds over the tropics of Titan, Saturn's largest moon.
The images clarify a long-standing mystery linking Titan's weather and surface features, helping astronomers better understand the moon of Saturn, viewed by some scientists as an analog to Earth when our planet was young.
The effort also served as the latest demonstration of adaptive optics, which use deformable mirrors to enable NSF's suite of ground-based telescopes to capture images that in some cases exceed the resolution of images captured by space-based counterparts.
[...]
On Titan, clouds of light hydrocarbons, not water, occasionally emerge in the frigid, dense atmosphere, mainly clustering near the poles, where they feed scattered methane lakes below.
Closer to the moon's equator, clouds are rare, and the surface is more similar to an arid, wind-swept terrain on Earth. Observations by space probes suggest evidence for liquid-carved terrain in the tropics, but the cause has been a mystery.
Regular monitoring of Titan's infrared spectrum suggests clouds increased dramatically in 1995 and 2004, inspiring astronomers to watch closely for the next brightening, an indicator of storms that could be imaged from Earth.
Schaller and her colleagues used NASA's Infrared Telescope Facility (IRTF), situated on Hawaii's Mauna Kea, to monitor Titan on 138 nights over a period of two years, and on April 13, 2008, the team saw a tell-tale brightening.
The researchers then turned to the NSF-supported Gemini North telescope, an 8-meter telescope also located on Mauna Kea, to capture the extremely high-resolution infrared snapshots of Titan's cloud cover, including the first storms ever observed in the moon's tropics.
The team suggests that the storms may yield precipitation capable of feeding the apparently liquid-carved channels on the planet's surface, and also influenced weather patterns throughout the moon's atmosphere for several weeks.
Global calamities like the one that doomed most dinosaurs forever alter the varieties of life found on Earth, but new research shows that it doesn't take a catastrophe to end entire lineages. An analysis of 200 million years of history for marine clams found that vulnerability to extinction runs in evolutionary families, even when the losses result form ongoing, background rates of extinction.
"Biologists have long suspected that the evolutionary history of species and lineages play a big role in determining their vulnerability to extinction, with some branches of the tree of life being more extinction-prone than others," said Kaustuv Roy, a biology professor at the University of California, San Diego, noting that human activities threaten some evolutionary lineages of living vertebrates more than others. "Now we know that such differential loss is not restricted to extinctions driven by us but is a general feature of the extinction process itself."
Roy and colleagues Gene Hunt of the Smithsonian Institution and David Jablonski of the University of Chicago report their findings in Science this week.
Their study focused on marine bivalves such as clams, oysters, mussels, and scallops, whose tough shells fossilize well to provide a rich record for study. By analyzing a global database of bivalve fossils stretching from the Jurassic Period to the present, the researchers noted when each genus disappeared and whether their relatives disappeared at the same time.
On average, closely related clusters of clams vanished together more often than expected by chance.
"Both background extinctions, which represent most extinctions in the history of life, and mass extinctions tend to be clumped into particular evolutionary lineages," Jablonski said.
The effect was particularly strong during the mass extinction at the end of the Cretaceous period, when clam lineages with the highest 'background' rates of extinction during more normal times were hardest hit. Three families with the highest background rates disappeared entirely. Two others, with rates more than twice the median, suffered heavy losses and have not recovered to this day.
"Big extinctions have a filtering effect. They tend to preferentially cull the more vulnerable lineages, leaving the resistant ones to proliferate afterwards," Hunt said.
When extinctions are scattered randomly across the evolutionary tree, the breadth of evolutionary history remains represented among living things, even when many species are lost. Clumped extinctions do the opposite, disproportionately removing the deeper history.
"Extinctions in the past and presumably in the future will lop off chunks of evolutionary trees, not just prune the trees and leave most of the history intact," Jablonski said.
China's first satellite to probe Mars has been transported to Russia for a launch later this year, state media reported Thursday.
Yinghuo-1, the 110-kilogramme (242-pound) Chinese satellite, is scheduled to be launched along with Russia's "Phobos Explorer" aboard a Zenit rocket in October after final testing, the Beijing News said.
After entering Mars' orbit -- 10 to 11 months later -- the orbiter will probe the Martian space environment, with a special focus on what happened to the water that appears to have once been abundant on the planet's surface.
The satellite, developed by the Shanghai Space Administration, will carry eight pieces of equipment including two cameras, the report said.
China refused to budge Wednesday on its demands that rich nations commit to large greenhouse gas cuts at upcoming climate change talks, while also declining to put a ceiling on its own emissions.
China and other developing nations will call on rich countries to cut greenhouse gas emissions by 40 percent by 2020 from 1990 levels at negotiations in Copenhagen in December, said Yu Qingtai, China's top climate negotiator.
"We have all along believed that due to the historical responsibility of the developed nations, they must continue to take the lead with large reductions beyond 2012," Yu told reporters.
We "have demanded that developed nations reduce emissions by 40 percent... this is fair and reasonable... China's position has not changed."
The December negotiations are aimed at hammering out a new climate change pact to replace the Kyoto protocol that expires in 2012.
As a developing nation with low per-capita emissions, China is not required to set emissions cuts under the UN Framework on Climate Change.
The European Union has said it will slash emissions by 20 percent by 2020 compared with the 1990 level.
The US Congress is considering legislation that would reduce US greenhouse gas emissions by 17 percent from 2005 levels by 2020.
China, the world's largest emitter of greenhouse gases along with the United States, has said neither of the cuts are enough.
Cray Inc. (NASDAQ: CRAY) today announced that the company has won the contract to install a next-generation supercomputer at the Department of Energy's (DOE) National Energy Research Scientific Computing Center (NERSC) located at the Lawrence Berkeley National Laboratory. The multi-year supercomputing contract includes delivery of a Cray XT5(TM) massively parallel processor supercomputer, which will be upgraded to a future-generation Cray supercomputer. When completed, the new Cray will deliver a peak performance of more than one petaflops (quadrillion mathematical calculations per second).
Like NERSC's current 355-teraflops Cray XT4(TM) system, nicknamed "Franklin," the new supercomputing system will help advance open science research in climate modeling, biology, environmental sciences, combustion, materials science, chemistry, geosciences, fusion energy, astrophysics, nuclear and high-energy physics, and other disciplines, along with scientific visualization of massive data sets. Click here for more information about the scientific work done on Franklin.
"As NERSC is the primary supercomputing center for DOE's Office of Science, making Cray's latest technology available to our users will accelerate innovation across a wide range of scientific disciplines, helping scientists tackle problems of vital importance to our nation's future," said Michael Strayer, Associate Director of DOE's Office of Advanced Scientific Computing Research.
According to NERSC Director Kathy Yelick, Cray was awarded the contract based on several factors, including performance and energy efficiency on a set of application benchmarks that capture the challenging workload of the 3,000 NERSC users.
"Because we serve such a large and scientifically diverse user community, it's critical that our systems deliver the best performance while running real-world applications -- especially as users scale their codes to run on tens of thousands of processor cores," Yelick said.
The new Cray system will provide many pioneering features, including the ability for users to customize the operating system for their own codes and to schedule jobs and access their data without logging in to the supercomputer. Yelick adds, "Cray's new cooling system and interconnect network technology mesh well with our research efforts into energy efficient computing and programming models."
"We are proud that NERSC chose Cray as its ongoing partner to provide its diverse and demanding users with advanced scientific computing capabilities," said Peter Ungaro, president and CEO of Cray. "Our partnership with NERSC expands beyond our supercomputers to working together to get the most efficient and effective use of the systems as possible -- a partnership that benefits all Cray customers around the globe. We are excited at the scientific achievements that NERSC's users have made on the Cray XT4 'Franklin' system, and we are looking forward to the advancements that will be made on both our Cray XT5 system as well as our future systems that are part of this contract."
Consisting of products and services, the multi-year contract is valued at over $50 million. The full system is expected to go into production in late 2010.
