Science is the poetry of Nature.







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Posts tagged "life"
What to think of these stars without any doubt similar to our sun, destined like the sun to keep alive an enormous quantity of creatures of every kind?
Angelo Secchi 1870 - “Le Soleil” (via kenobi-wan-obi)

laboratoryequipment:

Organic Farms Harbor Diversity

On average, organic farms support 34 percent more plant, insect and animal species than conventional farms, say Oxford Univ. scientists. Researchers looked at data going back 30 years and found that this effect has remained stable over time and shows no signs of decreasing.

“Our study has shown that organic farming, as an alternative to conventional farming, can yield significant long-term benefits for biodiversity,” says Sean Tuck of Oxford Univ.’s Department of Plant Sciences, lead author of the study. “Organic methods could go some way towards halting the continued loss of diversity in industrialized nations.”

Read more: http://www.laboratoryequipment.com/news/2014/02/organic-farms-harbor-diversity

(via kenobi-wan-obi)

mucholderthen:

The Evolution of Life

In its 4540 million (4.54 billion) years circling the sun, Earth has provided a home for life that has become more and more complex. [The timeline can be seen here in more detail.

  • for the last 3600 million years, simple cells (prokaryotes);
  • for the last 3400 million years, photosynthetic cyanobacteria
  • for the last 2000 million years, complex cells (eukaryotes);
  • for the last 1000 million years, multicellular life;
  • for the last 600 million years, simple animals;
  • for the last 550 million years, bilaterians,
    animals with a 
    front end and a back end,
    as well as an upside and a downside;
  • for the last 500 million years, fish and proto-amphibians;
  • for the last 475 million years, land plants;
  • for the last 400 million years, insects and plants with seeds;
  • for the last 360 million years, amphibians;
  • for the last 300 million years, reptiles;
  • for the last 200 million years, mammals;
  • for the last 150 million years, birds;
  • for the last 130 million years, flowers;
  • for the last 60 million years, the primates,
  • for the last 20 million years, the family Hominidae (great apes);
  • for the last 2.5 million years, the genus Homo (human predecessors);
  • for the last 200,000 years, anatomically modern humans.

Image retrieved here [source unknown]

distant-traveller:

Finding alien worlds on Earth

Have you ever wondered which places on Earth most resemble other planets? For some of us, imagining the landscape of other worlds might just be for fun, but scientists and engineers wonder about what the otherworldly places on Earth can tell us about neighbours like the Moon and Mars.

Working in the most unusual places on Earth can help us to prepare for human flights, robotic missions and the search for life beyond our own planet. These ‘analogues’ are chosen because they are similar in one way or another to particular planetary environments. They can be used for technical tests and research before the effort and expense of a launch into space.

The most hostile environments on Earth are home to unusual life forms. By studying these ‘extremophiles’ that can cope with extreme heat, cold, pressure or radiation on Earth, astrobiologists can consider whether certain environments in space might be home to similar tiny creatures. Needing unspoiled land, often without vegetation, means that astrobiologists and geologists often find themselves in very remote places.

Past research for ESA includes expeditions to Svalbard in conjunction with NASA. The teams visiting this remote island far to the north of Norway included geologists, biologists and engineers, and their tests included some of the instruments now working on Mars aboard the Curiosity rover.

Sites like the Atacama Desert, recently used to test a sampling rover for ESA’s ExoMars mission, are valuable. Trials can find out what sort of terrain a rover can cross, what kind of slopes it can go up and down, and whether it can sample the surface.

"We examined what kind of interesting areas there are on Mars and the Moon, and how to find something similar on Earth," says Oliver Angerer, Human Exploration Science Coordinator for ESA.

"For example, if you want to study lava tubes on Mars, what is the nearest equivalent on Earth? Depending on your mission requirements, you can choose Iceland, Hawaii or Tenerife."

And what about a Mars or Moon analogue as a holiday destination?

"There are a lot of places in this catalogue that I would like to visit," says Oliver. "So far, I haven’t been to the Dry Valleys in Antarctica, which is an amazing area for field activities. It’s the closest you can get to being on another planet while staying on Earth."

Image credit: ESA

Vaccine Refusals Fueled California’s Whooping Cough Epidemic : Shots - Health News : NPR

When the whooping cough vaccine was invented in the 1940s, doctors thought they had finally licked the illness, which is especially dangerous for babies. But then it came roaring back.

In 2010, a whooping cough outbreak in California sickened 9,120 people, more than in any year since 1947. Ten infants died; babies are too young to be vaccinated.

Public health officials suspected that the increased numbers of parents who refused to vaccinate their children played a role, but they couldn’t be sure.

(via callipygianology)

heythereuniverse:

Influenza Virus | kat m research

This negative-stained transmission electron micrograph (TEM) depicts the ultrastructural details of an influenza virus particle, or “virion”. A member of the taxonomic family Orthomyxoviridae, the influenza virus is a single-stranded RNA organism

neuromorphogenesis:

Hours after death, we can still bring people back

Resuscitation specialist Sam Parnia believes we can bring many more people back to life after they die – it’s just a matter of training and equipment

Are the people you resuscitate after cardiac arrest really dead? Isn’t the definition of death that it is irreversible?
A cardiac arrest is the same as death. It’s just semantics. After a gunshot wound, if the person haemorrhages sufficiently, then the heart stops beating and they die. The social perception of death is that you have reached a point from which you can never come back, but medically speaking, death is a biological process. For millennia we have considered someone dead when their heart stops beating.

People often confuse the terms cardiac arrest and heart attack. Clearly, they’re very different.
A heart attack happens when a clot blocks a blood vessel to the heart. The portion of the heart muscle that was supplied blood and oxygen by that vessel will then die. That’s why most people with a heart attack don’t die.

What is the biggest problem in bringing someone back to life?
Reversing death before the person has too much cell damage. People die under many different circumstances and under the watch of many different medical specialists. No single speciality is charged with taking and implementing all the latest advances and technology in resuscitation.

How long after they die can someone still be resuscitated?
People have been resuscitated four or five hours after death – after basically lying there as a corpse. Once we die the cells in the body undergo their own process of death. After eight hours it’s impossible to bring the brain cells back.

What is the best way to bring people back?
The ideal system – and they do this a lot in South-East Asia, Japan and South Korea – is called ECPR. The E stands for extra corporeal membrane oxygenation (ECMO). It’s a system in which you take blood from a person who has had a cardiac arrest, and circulate it through a membrane oxygenator, which supplies oxygen and removes carbon dioxide. Then you pump the blood back into circulation around the body. Using ECMO, they have brought people back five to seven hours after they died. ECMO is not routinely available in the US and UK, though.

So, when I go into cardiac arrest, ideally what steps do I want my doctors to take?
First, we start the patient on a machine that provides chest compressions and breathing. Then we attach the patient to a monitor that tells us the quality of oxygen that’s getting into the brain.

If we do the chest compressions and breathing and give the right drugs and we still can’t get the oxygen levels to normal, then we go to ECMO. This system can restore normal oxygen levels in the brain and deliver the right amount of oxygen to all the organs to minimise injury.

At the same time you also cool the patient. This slows the rate of metabolic activity in the brain cells to halt the process of cell death while you go and fix the underlying problem.

How do you cool the body?
It used to be ice packs. Today a whole industry has grown up around this, and there are two methods. One is to stick large gel pads onto the torso and the legs. These are attached to a machine that regulates temperature. When the body reaches the right temperature, it keeps it there for 24 hours. The other way is to put a catheter into the groin or neck, and cool the blood down as it passes by the catheter.

Cooling benefits the heart and all the tissues, but we focus on the brain. There are also new methods in which people are cooled through the nose. You put tubes in the nostrils and inject cold vapour to cool the brain down selectively before the rest of the body.

If I had a cardiac arrest today, what are the chances I would get all of that?
Almost zero.

Why isn’t this type of care routine?
Cardiac arrest is the only medical condition that will affect every single one of us eventually, unfortunately. What’s frightening is that the way we are managed depends on where we are and who is involved. Even in the same hospital, shift to shift, you will get a different level of care. There is no external regulation, so it’s left to individuals.

There is disagreement over the interpretation of near death experiences (NDEs) – such as seeing a tunnel or a bright light. When a person dies, when do these experiences shut off?
One of the last things to fall into the realm of science has been the study of death. And now we have pushed back the boundary of death. In order to ensure that patients come back to life and don’t have brain damage, we have to study the processes that go on after they die. Whether we like it or not, we have gone into the “afterlife” or whatever you want to call it.

For people who have NDEs, they are very real. Most are convinced that what they saw is a glimpse of what it’s like when we die. Most come back and have no fear of death, and are transformed in a positive way – becoming more altruistic. As a scientific community we have tried to explain these away, but we haven’t been successful.

So how can a doctor, or any person of science, deal with such otherworldly experiences?
We have to accept that these experiences occur, that they are real to the people who have them, in the same way that if a patient has depression you would never say, “I know that you are feeling depressed but that is just an illusion. I’m the doctor. I’m going to tell you what your feelings really mean.” But with NDEs, we do this all the time: “I know you think you saw this, but you really didn’t.”

Aren’t NDEs just hallucinations?
We know from clinical tests that the brain doesn’t function after death, therefore you can’t even hallucinate. It’s ridiculous to say that NDE people are hallucinating because you have to have a functioning brain. If I take a person in cardiac arrest and inject them with LSD, I guarantee you they will not hallucinate.

For your study of out of body experiences (OBEs), you placed images in hospital rooms on high shelves only someone floating near the ceiling could see. So far, two patients have had OBEs, but neither in a room with a shelf…
That’s right. We had 25 hospitals that had an average of 500 beds working on the study. To put a shelf above every single bed, we would have to put up 12,500 shelves. That was completely unmanageable. We selected areas where cardiac arrest patients are frequently treated but even with that, at least half of those who had cardiac arrests and survived were in areas without shelves.

Are you continuing the experiment?
Yes. It’s part of an overall package to improve resuscitation to the brain. We are trying not to forget during resuscitation that there’s a human being in there.

In your book, you imply that death might be pleasant. Why do you think that?
The question is, what happens to human consciousness – the thing that makes me into who I am – when my heart stops beating and I die? From our external view, it looks like it simply disappears. But it sort of hibernates, in the same way as it does when you are given a general anaesthetic. And it comes back. I don’t believe that your consciousness is annihilated when you reach the point of death. How far does it continue? I don’t know. But I do know that at least in the period of time in which we can bring people back to life that entity of the human mind has not been annihilated.

What does this mean?
Those people who have pleasant experiences after death suggest that we should not be afraid of the process. It means there is no reason to fear death.

(Image: Martin Adolfsson)

Microscopic Life Captured in a Plankton Net

The photo above shows a sample of water teeming with microscopic life.

The sample was collected in a plankton net suspended into an incoming tide for 20 minutes from a bridge over an inlet near Brunswick, Maine. It was later photographed in a lab at the Southern Maine Community College. Several diatoms (aquatic, photosynthetic plants) can be identified here.

The round, cathedral window like structure is a stepanodiscus and the connected, rectangular tubes are tabellaria. Diatoms are at the bottom of the food chain, meaning that nearly all life depends upon these creatures. They produce as much as 50 percent of the Earth’s oxygen. — Paula Ursoy and John Stetson

Life Confirmed in Buried Antarctic Lake

Blobs and smears of microbial life growing in clear plastic disks are confirmation of a community living in a lake buried beneath the Antarctic ice, scientists studying the lake have said.

Water retrieved from subglacial Lake Whillans contains about 1,000 bacteria per milliliter (about a fifth of a teaspoon) of lake water, biologist John Priscu of Montana State University told Nature News. Petri dishes swiped with samples of the lake water are already growing colonies of microbes at a good rate, Nature News reported.

Lake Whillans is 2,625 feet (800 meters) below the West Antarctic Ice Sheet. After breaking through the ice on Jan. 28, researchers are returning to the United States with 8 gallons (30 liters) of lake water and eight sediment cores from the lake bottom. These samples will be tested for signs of microbial life, which could shed light on the types of extreme life that is able to thrive in such harsh environments.

Now, I don’t want to get people too excited but just imagine what the results could imply for a future mission to the Galilean satellite, Europa.

fuckyeahoceancreatures:

Starfish feeding on a dead whale.

For the actual video: http://www.youtube.com/watch?v=HG17TsgV_qI

(via freshphotons)

amolecularmatter:

“Weird Life”: The Story of the Cell

“The synthesis of life, should it ever occur, will not be the sensational discovery which we usually associate with the idea. If we accept the theory of evolution, then the first dawn of the synthesis of life must consist in the production of forms intermediate between the inorganic and the organic world, forms which possess only some of the rudimentary attributes of life, to which other attributes will be slowly added in the course of development by the evolutionary action of the environment.” - Stephane Leduc, 1911

In July 2007, a group of scientists associated with the American Research Council issued a report about something they termed “weird life.” Weird life, they said, could be life in a form that we have never seen before - an organism may not depend on water, for example, or it may have a completely different, non-nucleic-acid based system of heredity and still be alive. Their definition of weird life was vague, and not by accident: One of the primary challenges in the discussion of life, both on earth and elsewhere in the universe, is that life itself is a very difficult thing to parameterise. As David Greer, a professor of physics at New York University, says, “There is no mathematically rigorous definition of life.” Our determination of life is based entirely on our own human experience, and thus its working definition is less a set of functional rules for classification and more a set of somewhat ambiguous statements designed to organise the unknown. The precise problem with trying to organise the unknown, of course, is that nothing is known about it; but without a reconcilable definition of life - or “weird life”, as the case may be - we don’t even know where to start looking.

The key, I think, to this almost certainly inaccurate (and definitely not mathematically rigorous) but working definition is to explore how life came about in the first place. This serves two purposes: First, the definition of life could arguably be based on the most basic conditions necessary for it to occur, and second, life in its most rudimentary forms are more likely to be homogenous across biological systems (however more complex or different from our own) than the large-scale plants and animals we traditionally associate with life. In addition, the makeshift definition should be written as a set of provable postulates, and should be sufficiently inclusive to potentially apply to all forms of aptly labeled “weird life” without being overly promiscuous, so to speak.

The Primordial Soup’s Gone Off

Ever since Stanley Miller’s infamous experiment in 1953, the long-time leading hypothesis into the origin of life was his theory, built around the reducing atmospheric gases of early earth and electric charge passing through them in the form of lightning. Miller’s experiment, which has been replicated, successfully showed that shooting a spark through reducing gases in a laboratory beaker produces biomolecules - in Miller’s case, approximately 10 amino acids and several nucleic acid precursors, although others who have repeated the experiment have had rather more success. The experiment illustrates clearly that life could have begun this way.

image

Of course, the origin of life is still a black box; in reality any number of plausible hypotheses could be correct. However, for me there are several unaddressed issues in Miller’s experiment that make me skeptical that it is the whole story behind the evolution of us. The primary issue is simply time; the earth is only 4.5 billion years old, and the oldest microfossils of early cell-like structures that have been found date back 3.5 billion years. While a billion years seems like - well, a billion years to us, it’s actually quite quick on an evolutionary timescale. To me, this means that life didn’t simply come down to a lucky lightning strike - it indicates that there was a driving force behind its development that pushed it forward faster.

In 1993, a different theory for the origin of life - termed the hydrothermal vent idea - came into prevalence. It suggested that instead of a collection of atoms in the early ocean, life came out of deep-sea hydrothermal vents. There is much compelling evidence for this idea; two of the most compelling bits, I think, are the existence of an energy disequilibrium and the interconnected micropores found on the vents’ surface. 

The ocean, even on the early earth, was a fairly stagnant place in terms of energy gradients; lightning strikes could perhaps have caused them sporadically, but in different locations and to varying degrees with very little continuity. Hydrothermal vents, on the other hand, are rich in energy disequilibrium, boasting temperature, pH, and redox gradients. 

So why are energy gradients so important? Because for cells, harnessing energy as ion gradients is about as universal as the genetic code. A new paper recently published in Cell postulates that tiny micropores found on the surface of deep-sea vents - conveniently approximately the diameter of a cell - could have been the starting point of life on earth. In modern cells, about 75% of a cell’s ATP budget - or biological energy - goes into making proteins; conversely, ATP is replenished by proteins that harness chemiosmotic gradients. The paper postulates that the energy disequilibrium provided by hydrothermal vents - specifically, that sustained disequilibrium at a submarine hydrothermal vent interfacing with ocean water - generates conditions that thermodynamically favour the formation of life’s building blocks, particularly amino acids, in the presence of hydrogen gas, carbon dioxide, and ammonium. If a leaky membrane built of lipid precursors accumulated near a vent, the budding system would have a ready-made metabolism by exploiting the pre-existing chemiosmotic gradient. Once enough precursors accumulated, and the “metabolism tap” was shut off due to the newly formed “membrane“‘s impermeability, natural selection would strongly favour cells with simple antiporters that could continue to exploit the ion gradient. 

Defining Life from Vents

If, for the sake of argument, the thermal vent hypothesis is found to be the way things actually were, what then? What about life? Defining life by the characteristics of the first cell does not appeal to me; this leads to a definition of characteristics that are shared because they originate from a common ancestor, and not because they are actually fundamental to life. However, the hydrothermal vent hypothesis does, I think, enhance our understanding of what is needed for life, at least on this planet, and based upon the need for a biochemical gradient for protein production and the necessity of a lineage to exploit progress made in the previous generation, I would define life as:

  1. A physical compartment across the walls of which energy can be generated and utilised for biochemical reactions, and; 
  2. one that possesses a material of heredity that may be passed to the next generation.

It’s not a particularly restrictive definition, nor is it likely broadly accurate. However, the fact remains that there are many definitions of life; few widely agreed upon, and certainly none reasonably consented to in their entirety without special cases. Considering what was necessary for the first cell to form is as valid a method of organising the unknown as any other, and perhaps, one day, we’ll be able to find a distinctly new organism somewhere in the universe, one that shifts our entire paradigm on biochemistry, heredity, and what it means to fundamentally be alive. Until then, I think, formal and constructive definitions will elude us, and “weird life” will continue to be - well, weird.

An Afterthought: The Interesting Case of Protocells

In his TedX talk, Martin Hanczyc outlined a very similar definition of life to the one I derived from the assumed origin of life inside thermal vents. It can be reasonably summarised in three words:

  1. Body;
  2. Metabolism;
  3. Heredity.

He works extensively with oil and water systems, designing in vitro protocells. He also works with tar systems to simulate the stuff of the early universe, like those in the images at the top of this post; his protocells are comprised of single-digit numbers of chemicals, and yet are able to locate food, respond to one another within an environment, and even divide and hybridise into wholly new organisms with new functional characteristics. 

So are these protocells alive? Martin Hanczyc believes that nothing can be considered “alive” in a black-and-white way; rather, these protocells fall somewhere in the range of an intermediate between the inorganic and organic world, and while they possess some attributes necessary for life they simply fall on a continuum along with humankind and this desk. A video of his TedX talk, in which he explains further, can be found here.

image

Due to its length and their quantity, references in this post are cited using links where they are most relevant. Most of the information used comes from a new paper in Cell on the Origin of Membrane Bioenergetics (Martin and Lane, 2012), and Martin Hancycz’s TedX talk. For another take on Martin Hancycz’s work, see this post here.

wespeakfortheearth:

How do coral reef conservationists balance the environmental needs of the reefs with locals who need the reefs to survive? Joshua Drew draws on the islands of Fiji and their exemplary system of protection, called “connectivity”, which also keep the needs of fishermen in mind.

Lesson by Joshua Drew, animation by Veronica Wallenberg

ikenbot:

Are We Living Inside a Computer Simulation?

The popular film trilogy, The Matrix, presented a cyberuniverse where humans live in a simulated reality created by sentient machines.

Now, a philosopher and team of physicists imagine that we might really be living inside a computer-generated universe that you could call The Lattice. What’s more, we may be able to detect it.

In 2003, British philosopher Nick Bostrom published a paper that proposed the universe we live in might in fact really be a numerical computer simulation. To give this a bizarre Twilight Zone twist, he suggested that our far-evolved distant descendants might construct such a program to simulate the past and recreate how their remote ancestors lived.

He felt that such an experiment was inevitable for a supercivilization. If it didn’t happen by now, then in meant that humanity never evolved that far and we’re doomed to a short lifespan as a species, he argued.

To extrapolate further, I’d suggest that artificial intelligent entities descended from us would be curious about looking back in time by simulating the universe of their biological ancestors.

As off-the-wall as this sounds, a team of physicists at the University of Washington (UW) recently announced that there is a potential test to seen if we actually live in The Lattice. Ironically, it would be the first such observation for scientifically hypothesized evidence of intelligent design behind the cosmos.

The UW team too propose that super-intelligent entities, bored with their current universe, do numerical simulations to explore all possibilities in the landscape of the underlying quantum vacuum (from which the big bang percolated) through universe simulations. “This is perhaps the most profound quest that can be undertaken by a sentient being,” write the authors.

Before you dismiss this idea as completely loony, the reality of such a Sim Universe might solve a lot of eerie mysteries about the cosmos. About two-dozen of the universe’s fundamental constants happen to fall within the narrow range thought to be compatible with life. At first glance it seems as unlikely as balancing a pencil on its tip. Jiggle these parameters and life as we know it would have never appeared. Not even stars and galaxies. This is called the Anthropic principle.

ANALYSIS: Building the Universe Inside a Supercomputer

The discovery of dark energy over a decade ago further compounds the universe’s strangeness. This sort of “antigravity” pushing space-time apart is the closest thing there is to nothing and still is something. This energy from the vacuum of space is 60 orders of magnitude weaker that what would be predicted by quantum physics.The eminent cosmologist Michael Turner ranks dark energy as “the most profound mystery in all of science.”

We are also living at a very special time in the universe’s history where it switched gears from decelerating to accelerating under the push of dark energy. This begs the question “why me why now?” (A phrase popularly attributed to Olympic figure skater Nancy Kerrigan in 1994 when she was attacked and crippled by an opponent.)

If dark energy were slightly stronger the universe would have blown apart before stars formed. Any weaker and the universe would have imploded long ago. Its incredibly anemic value has been seen as circumstantial evidence for parallel universes with their own flavor of dark energy that is typically destructive. It’s as if our universe won the lottery and got all the physical parameters just right for us to exist.

Finally, an artificial universe solves the Fermi Paradox (where are all the space aliens?) by implying that we truly are alone in the universe. It was custom made for us by our far-future progeny.

Biblical creationists can no doubt embrace these seeming cosmic coincidences as unequivocal evidence for their “theory” of Intelligent Design (ID). But is our “God” really a computer programmer rather than a bearded old man living in the sky?

Currently, supercomputers using a impressive-sounding technique called lattice quantum chromodynamics, and starting from the fundamental physical laws, can simulate only a very small portion of the universe. The scale is a little larger than the nucleus of an atom, according UW physicist Martin Savage. Mega-computers of the far future could greatly expand the size of the Sim Universe.

ANALYSIS: Artificial Universe Created Inside a Supercomputer

If we are living in such a program, there could be telltale evidence for the underlying lattice used in modeling the space-time continuum, say the researchers. This signature could show up as a limitation in the energy of cosmic rays. They would travel diagonally across the model universe and not interact equally in all directions, as they otherwise would be expected to do according to present cosmology.

If such results were measured, physicists would have to rule out any and all other natural explanations for the anomaly before flirting with the idea of intelligent design. (To avoid confusion with the purely faith-based creationist ID, this would not prove the existence of a biblical God, because you’d have to ask the question “why does God need a lattice?”)

If our universe is a simulation, then those entities controlling it could be running other simulations as well to create other universes parallel to our own. No doubt this would call for, ahem, massive parallel processing.

If all of this isn’t mind-blowing enough, Bostrom imagined “stacked” levels of reality, “we would have to suspect that the post-humans running our simulation are themselves simulated beings; and their creators, in turn, may also be simulated beings. Here may be room for a large number of levels of reality, and the number could be increasing over time.”

To compound this even further, Bostrom imagined a hierarchy of deities, “In some ways, the post-humans running a simulation are like gods. However, all the demigods except those at the fundamental level of reality are subject to sanctions by the more powerful gods living at lower levels.”

If the parallel universes are all running on the same computer platform could we communicate with them? If so, I hope the Matrix’s manic Agent Smith doesn’t materialize one day.

To borrow from the title of Isaac Asimov’s novel I Robot, the human condition might be described as I Subroutine.

(via kenobi-wan-obi)

sagansense:

Origin Of Life: New Study Spotlights Not Chemistry But How Living Things Store, Process Information

Scientists trying to unravel the mystery of life’s origins have been looking at it the wrong way, a new study argues.

Instead of trying to recreate the chemical building blocks that gave rise to life 3.7 billion years ago, scientists should use key differences in the way that living creatures store and process information, suggests new research detailed today (Dec. 11) in the Journal of the Royal Society Interface.

“In trying to explain how life came to exist, people have been fixated on a problem of chemistry, that bringing life into being is like baking a cake, that we have a set of ingredients and instructions to follow,” said study co-author Paul Davies, a theoretical physicist and astrobiologist at Arizona State University. “That approach is failing to capture the essence of what life is about.”

Living systems are uniquely characterized by two-way flows of information, both from the bottom up and the top down in terms of complexity, the scientists write in the article. For instance, bottom up would move from molecules to cells to whole creatures, while top down would flow the opposite way. The new perspective on life may reframe the way that scientists try to uncover the origin of life and hunt for strange new life forms on other planets.

“Right now, we’re focusing on searching for life that’s identical to us, with the same molecules,” said Chris McKay, an astrobiologist at the NASA Ames Research Center who was not involved in the study. “Their approach potentially lays down a framework that allows us to consider other classes of organic molecules that could be the basis of life.”

Chemical approach
For decades, scientists have tried to recreate the primordial events that gave rise to life on the planet. In the famous Miller-Urey experiments reported in 1953, scientists electrically charged a primordial soup of chemicals that mimicked the chemical makeup of the planet’s early oceans and found that several simple amino acids, the most primitive building blocks of life, formed as a result.

But since then, scientists aren’t much further along in understanding how simple amino acids could have eventually morphed into simple, and then complex, living beings.

Part of the problem is that there isn’t really a good definition of what life is, said Sara Walker, study co-author and an astrobiologist at Arizona State University.

“Usually the way we identify life on Earth is always by having DNA present in the organism,” Walker told LiveScience. “We don’t have a rigorous mathematical way of identifying it.”

Using a chemical definition of life — for instance, requiring DNA — may limit the hunt for extraterrestrial life, and it also may wrongly include nonliving systems, for instance, a petri dish full of self-replicating DNA, she said.

Information processing
Walker’s team created a simple mathematical model to capture the transition from a nonliving to a living-breathing being. According to the researchers, all living things have one property that inanimate objects don’t: Information flows in two directions.

For instance, when a person touches a hot stove, the molecules in his hand sense heat, transmit that information to the brain, and the brain then tells the molecules of the hand to move. Such two-way information flow governs the behavior of simple and complex life forms alike, from the tiniest bacteria to the giant humpback whale. By contrast, if you put a cookie on the stove, the heat may burn the cookie, but the treat won’t do anything to respond.

Another hallmark of living beings is that they have different physical locations for storing and reading information. For instance, the alphabet of letters in DNA carries the instructions for life, but another part of the cell, called the ribosome, must translate those instructions into actions inside the cell, Davies told LiveScience.

(By this definition, computers, which store data on a hard drive and read it off using a central processing unit, would have the hallmarks of life, although that doesn’t mean they are alive per se, Walker said.)

The new model is still in its infancy and doesn’t yet point to new molecules that could have spawned life on other planets. But it lays out the behavior needed for a system needs to be considered living, Walker said.

“This is a manifesto,” said Davies. “It’s a call to arms and a way to say we’ve got to reorient and redefine the subject and look at it in a different way.”

(via kenobi-wan-obi)