Please create an account to participate in the Slashdot moderation system

 


Forgot your password?
Close
typodupeerror
×
Science

Tracking Down the First Oxygen Users 109

Posted by samzenpus from the primordial-home-health-care dept.
sciencehabit writes "None of us would be here today if, billions of years ago, a tiny, single-celled organism hadn't started using oxygen to make a living. Researchers don't know exactly when this happened, or why, but a team of scientists has come closer than ever before to finding out. They've identified the earliest known example of aerobic metabolism, the process of using oxygen as fuel. The discovery may even provide clues as to where the oxygen came from in the first place."
This discussion has been archived. No new comments can be posted.

Tracking Down the First Oxygen Users More

Tracking Down the First Oxygen Users

Comments Filter:

  • Where the oxygen came from... (Score:4, Insightful)

    by jeffmeden ( 135043 ) on Wednesday January 11, 2012 @01:47PM (#38665956) Homepage Journal

    The discovery may even provide clues as to where the oxygen came from in the first place.

    Shouldn't they be looking for the carbon dioxide eaters?

    • Re:Where the oxygen came from... (Score:5, Informative)

      by SJHillman ( 1966756 ) on Wednesday January 11, 2012 @01:53PM (#38666020)

      We already know the guys who produced the oxygen (or at least we have a good idea), we're interested in the ones who used it.

      • Re: (Score:1)

        by Anonymous Coward

        Actually the heterotroph hypothesis theorizes that plants came second, after a ton of Carbon Dioxide was produced, and was opportunistically consumed by autotrophs, which are assumed to have emerged later due to the innate complexity of autotrophic metabolism. But was the carbon dioxide produced by anaerobic organisms like yeast? Meh... it's a hypothesis for a reason. Maybe aerobic heterotrophs pre-date oxygen producing autotrophs... ?

      • Re: (Score:2, Funny)

        by Anonymous Coward

        Simple. The first oxygen users should have low ID's.

    • My understanding from reading Oxygen by Nick Lane is that atmospheric oxygen at levels high enough to sustain oxygen based metabolism came from plants and trees being buried and not consumed which would have used the oxygen in the consumption. The buried plants and trees became our fossil fuels.

      disclaimer: I'm a programmer by profession, just a layman reader in molecular biology.

      • Re:Where the oxygen came from... (Score:5, Informative)

        by turbidostato ( 878842 ) on Wednesday January 11, 2012 @02:32PM (#38666510)

        "My understanding ... is that atmospheric oxygen at levels high enough to sustain oxygen based metabolism came from plants and trees"

        Your understanding is quite wrong.

        By the time there were "plants and trees" the major part of the biosphere already was oxigen dependant.

        The change of the atmosphere from reductive to oxidative predates trees by about two billion years -the start of the proterozoic age is marked about 2.4 billion years ago (with a strong spike around the precambric which still predates trees by about 300 million years).

        • Re: (Score:3, Interesting)

          by The Grim Reefer ( 1162755 )

          "My understanding ... is that atmospheric oxygen at levels high enough to sustain oxygen based metabolism came from plants and trees"

          Your understanding is quite wrong.

          By the time there were "plants and trees" the major part of the biosphere already was oxigen dependant.

          The change of the atmosphere from reductive to oxidative predates trees by about two billion years -the start of the proterozoic age is marked about 2.4 billion years ago (with a strong spike around the precambric which still predates trees by about 300 million years).

          It's my understanding that cyanobacteria [wikipedia.org] is responsible for initially creating earths oxygen. I can't say I know much about the historical aspect of it. But I used to keep saltwater reef/fish tanks, and it can become a big problem if you do something wrong. It's really nasty slimy algae looking stuff. I used to find in ironic how much many fish keepers despised the stuff, and yet we probably wouldn't be here without it.

          • Re:Where the oxygen came from... (Score:4, Informative)

            by djl4570 ( 801529 ) on Wednesday January 11, 2012 @04:23PM (#38667824) Journal
            Cyanobacteria changed the chemistry of the oceans as well. Before oxygen production the oceans contained large quantities of dissolved iron. When oxygen was produced the dissolved iron oxidized and precipitated out as rust. The banded iron formations are a relic of this epoch. It wasn't until the oceans reached equilibrium between oxygen and iron that surplus oxygen was released into the atmosphere.
            • I would guess that cyanobacteria also bound large quantities of iron, phosphorus and nitrogen as it metabolizes all three. I knew of several people who could not get rid of the stuff. In the end they used media that phosphates would bind to.

            • I remember reading about this in Oxygen, thanks for the clarification, but as I understood it oxygen is consumed when the plant or bacteria or trees that generated the oxygen with photosynthesis is combusted, and it is primarily the buried plants that are now fossil fuels that established a significant atmospheric level of oxygen that sustains oxygen based metabolism. Other than the buried plants that weren't combusted (decayed, etc) oxygen and carbon dioxide are consumed in photosynthesis and decay and oxy

              • Re: (Score:2)

                by djl4570 ( 801529 )
                Calcium carbonate or limestone is a much larger carbon repository than fossil fuels. I am working from memory here but IIRC photosynthesis fixes atmospheric carbon dioxide by using sunlight to hydrolyze water. The reactions take the hydrogen from the water to create hydrocarbons and free oxygen. A significant volume of the carbon consumed goes into skeletons and shells. Vast quantities of marine life formed shells made of calcium carbonate which eventually sank to sea floor to become limestone.

                • That's interesting, but just to clarify, I mention the fossil fuels not as fixing carbon but as freeing up the oxygen that makes up atmospheric oxygen (about 21 percent of the atmosphere).

                  This is never mentioned publically and interestingly neither acknowledged nor disputed in this thread.

                  • You can understand carbon storage as a shorthand for "freeing up the oxygen" (I've probably never seen this term used before). From this point of view fossil fuels don't really differ from limestone -- both are geological structures which contain a lot of carbon a store it "indefinitely". Of course the limestone will one day be recycled in the mantle and we burn the fossil fuels like there is no tomorrow.

          • "It's my understanding that cyanobacteria is responsible for initially creating earths oxygen."

            Which are neither plants nor trees.

        • I don't understand that. As I read any early atmospheric oxygen combined with iron, and it was only photosynthesis being adapted by plants and trees that emitted a new source of oxygen, and unconsumed plants and trees that left sufficient oxygen for multi-cellular organisms based on an oxygen metabolism, as I understand it that and incorporating mitochondria pretty much required for multi-cellular organisms.

          Single cells able to use oxygen in their metabolism, like mitochondria, existed to be adapted but I t

          • Re: (Score:2)

            by Opyros ( 1153335 )
            It was long before there were any animals or trees. Google "oxygen catastrophe" or "great oxygenation event" for how it happened.

          • correction: plants and trees.

            And yeah, I saw trees came way later, but whatever was buried and became fossil fuels, plants of some type.

          • Re: (Score:2)

            by ArcherB ( 796902 )

            Unable to rename log file. File in use.

            Killed hbsend and tried again, worked fine.

            Nothing lived outside the oceans until the ozone layer formed. The ozone didn't form until there was enough oxygen in the atmosphere. This oxygen was produced by oceanic algae.

          • Oxygen began in the oceans not the atmosphere.

          • This was downmodded Overrated -1 when it hasn't even received a positive mod rating. What is that, an attempt to hide my comment from view? That's just censorship. If there's something wrong with the comment then say what it is. I don't sEe anything wrong with it other than a typo in last word which I followed up with a post correcting it.

            I notice in certain topics (GW, IPV6 for example) we have a lot of censorship going on with people downmodding what they don't like. Why don't we just be honest and call t

          • I thought oxygen was pretty scarce until photosynthesis was used widely by plants and animals.

            Photosynthesis was happening long long before plants or animals existed. A number of lines of bacteria (neither plant nor animal) had photosynthetic mechanisms, and one of these lines was co-opted by what became plants to provide them with a pre-packaged "black box" of energy and sugar production, given light and environmental CO2. Those bacteria raised the oxygen concentrations in the environment by some tens of t

            • Thanks for the info, but I didn't learn this in school, I am undertaking extensive readings in molecular biology. I learned this in Oxygen by Nick Lane, and I think the points I made about what established the oxygen levels to sustain multiicellular organisms is correct. It was buried undecayed plants that established sufficient oxygen (GT 15 percent) to sustain organisms according to what I read. I find that fossil fuel matter made breathing possible to be fascinating and it is not only not taught in schoo

              • I've definitely read stuff by Nick Lane, and if I could access Amazon here, I'd be able to find if "Oxygen" is still on my wishlist, or if I'd actually read it. It's certainly been under consideration.

                I have a suspicion that you've been misunderstanding something, but since I don't recall reading Lane's book, I think I'd better wait until I have read it.

                Question (relevant) : are you familiar with Margulis' well-accepted theory of the origin of complex unicellular organisms by endosymbiosis between previou

                • Yes, Lane refers to it in all three of the books I have of his, but extensively in Power, Sex, Suicide, about mitochondria. Refers to her oxygen holocaust theory in Oxygen.

                  I see that oxygen levels were as much as 18 percent prior to Cambrian, didn't realize they were that high so definitely misunderstood the specific effect on oxygen levels that fossil fuel matter had, but still Lane contends that oxygen levels are essentially the mismatch of uncombusted life due to being buried and protected from decay, ot

                  • Margulis had the relatively rare pleasure of being proved right, in the teeth of pretty solid opposition, in her own life time. But she's also gone a bit OTT with the idea too, straining to wedge many other features of different taxons into other events of endosymbiosis, for which the evidence is much weaker. But she's definitely contributed more than the average room full of professors.

              • "I find that fossil fuel matter made breathing possible to be fascinating and it is not only not taught in schools, it is virtually unaddressed including all who replied to me in this thread."

                Maybe it is because it's a f* obviety. ...were it not because it is not "fossil fuel" but "fossil (mainly) carbonated structures". You wouldn't consider the White Cliffs of Dover, to name a famous example, to be "fossil fuel matter", would you?

                • no, I wouldn't, but I wasn't referring to the White Cliffs of Dover, I was referring to fossil fuel matter (I.e. plants buried that became coal and oil).

                  In a later post I stated I overemphasized the impact of uncombusted fossil fuel matter to oxygen levels after revisiting it but it was part of the process.

        • Re: (Score:2)

          by na1led ( 1030470 )
          It all happend about 6,000 years ago. God spit out Air, Plants, Animals, and Humans, all at once, and you can't convince me otherwise!

    • http://en.wikipedia.org/wiki/Photosynthesis [wikipedia.org]

        process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight.

    • Look hard enough and you'll find an ancient civilization who built forests of artificial CO2 sequestering trees [slashdot.org].

    • I thought stromatolites were the first.

    • Shouldn't they be looking for the carbon dioxide eaters?

      Well, if you want to find the first organisms that produced oxygen from carbon dioxide, then that might be a useful route to take. But if it turns out that the first oxygen producers did it by consuming something other than carbon dioxide, then you'd be answering the wrong question.

      Indeed, if you'd read TFA, you'd realise that they were very specifically looking at molecular evidence for the origin of the ability to produce oxygen by digesting hydroge

  • Oxidizer, not fuel (Score:5, Informative)

    by Un pobre guey ( 593801 ) on Wednesday January 11, 2012 @01:49PM (#38665970) Homepage
    Oxygen is not the fuel. It is the oxidant to the fuel to release energy.

    • Re:Oxidizer, not fuel (Score:5, Insightful)

      by Aguazul ( 620868 ) on Wednesday January 11, 2012 @01:56PM (#38666058) Homepage
      In a hydrocarbon atmosphere, you can burn oxygen. All our definitions are oriented around our oxygen-based atmosphere. I'm sure we'd call oxygen 'fuel' if we lived in a hydrocarbon atmosphere and oxygen was the scarcer material.

      • After all, no matter how you present it, it's just a chemical reaction: 2 molecules and some energy. "Fuel" and "fire" and "burn" are all just lies to children. Either that, or Iron is also a "fuel" with an end result of "rust" ash. Low "burning" temperature, and low heat output, as it doesn't take much for Iron to react with oxygen.

        • Interesting point. On a geologic timescale, "rust" is a flash fire.

          Still, colloquial English words are based on current human experience of time and matter. Even an ember flashing to fire in a pure-oxygen atmosphere, the ember is considered fuel, even if it's outmassed by the oxygen available for the reaction.

          Also, from a chemical perspective, in most chemical reactions involving oxygen, oxygen is the oxidizing agent and the other element or compound is the reducing agent. (Maybe all? I can't think of any r

          • Re:Oxidizer, not fuel (Score:5, Interesting)

            by Samantha Wright ( 1324923 ) on Wednesday January 11, 2012 @03:15PM (#38667046) Homepage Journal
            Oxygen is the most aggressively electronegative element after Fluorine. (I think that Neon might be [wikipedia.org] even more aggressive if you could ionize it usefully.) I had a colourful mnemonic for this in second-year organic chemistry that revolved around bitches and gimps, but the take-home message is that Chlorine robs Nitrogen, and Oxygen wipes out everything but good ol' Fluorine. For related reasons, fluorine becomes a source of face-melting death in hydrogen-bonded form.

            • For related reasons, fluorine becomes a source of face-melting death in hydrogen-bonded form.

              Meh.

              This blog may give you a warm and cuddly feeling about good ol' fluorine : Sand Won't Save You This Time [corante.com]

              For a taste :

              It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water - with which it reacts explosively.

              If you don't know what "hypergo

              • A friend of mine was working in an organic chemistry lab with a particularly cavalier graduate student once who had the nerve to open a vial of triflic acid [wikipedia.org] outside of the fume hood. It began protonating the air around it and gave them both nosebleeds. (Said graduate student was ejected shortly after he got his PhD, for an unrelated reason.)
                • "Triflic" ... well, you've managed the uncommon by stumping me. That's one I've never heard of, at least by that name. [follows link] Trifluoromethanesulphonic acid. Ohh, sounds good already.

                  "dangerously exothermic."

                  Can you set that to music .... oh no, it's all right, I hear it's siren song.

                  Yes, on a scale of zero to "no" ... well, it's not something I'd keep under the kitchen sink with children around. Or cats. Or most adults, to be honest. Me included.

        • Re: (Score:2)

          by khallow ( 566160 )

          Either that, or Iron is also a "fuel" with an end result of "rust" ash. Low "burning" temperature, and low heat output, as it doesn't take much for Iron to react with oxygen.

          Iron is a fuel and you can burn it in the usual sense [wikipedia.org] when temperatures get hot enough (along with good air circulation).

        • And Iron [wikipedia.org] is an amazingly reactive [youtube.com] fuel if you get it hot enough in the right concentrations.

        • I don't know about you, but I've actually lit "iron" on fire. Quite easy if you have the right kind. Go get some Steel Wool and use a battery pack attach positive to one side, and negative to another and start chanting "Burn Baby Burn" ...

        • Re:Oxidizer, not fuel (Score:5, Informative)

          by mcgrew ( 92797 ) * on Wednesday January 11, 2012 @03:02PM (#38666884) Homepage Journal

          "Fuel" and "fire" and "burn" are all just lies to children.

          Not lies to children, but the obvious. Of course, what may seem obvious often isn't ("the world is flat"). You and I know that if you combine a piece of wood and oxygen, both are converted, but you have to know how it works first. But at any rate, "fire" is a synonym of "oxidation". Fire is what you get when you combine a combustable material, oxygen, and heat. It's real, it's no lie. The combustable material is the fuel, oxygen is the oxident, and "burn" is the conversion of the fuel and oxygen to a different form. It's semantics, not lies.

          Either that, or Iron is also a "fuel" with an end result of "rust" ash.

          Actually, rust is steel's ashes, and you can make steel burn quite fast of you get it hot enough; ask any blacksmith. You can make sparklers out of pieces of wire coat hangers or bailing wire, coated with saltpeter mixed with flour or sugar. The sparkles on any sparkler you buy at a fireworks stand is the steel's flames, and that's exactly what you see if you put a thin piece of steel in a forge with the bellows going. Take the steel out of the fire and it sparkles like a sparkler, and leaves rust behind.

          • Re: (Score:2)

            by Hatta ( 162192 )

            Fire is what you get when you combine a combustable material, oxygen, and heat. It's real, it's no lie. The combustable material is the fuel, oxygen is the oxident, and "burn" is the conversion of the fuel and oxygen to a different form. It's semantics, not lies.

            I agree, it's not lies. But we also have to remember that it's still just semantics. There's no reason not to consider oxygen the fuel and carbohydrates the reducing agent.

            • Maybe I should have air-quoted "lies to children" -- this is a term commonly used to refer to the oversimplification of scientific processes to put them in terms that children can understand, but which aren't necessarily totally scientifically correct.

              As such, "Fuel," "fire," "burn," and "lies to children" are all semantics.

              Burning falls under the same category as, say jumping. We describe jumping as using our legs to push our bodies up and away from the ground to overcome the effects of the earth's gravit

      • All our definitions are oriented around our nitrogen-based atmosphere.

        FTFY. [noaa.gov]

        • What a wonderful new piece of knowledge! This vacuum-based Universe we're living in never ceases to amaze me!

        • Re: (Score:2)

          by khallow ( 566160 )

          All our definitions are oriented around our oxygen-based atmosphere.

          FTFY.

          FTFY. One would not call a bottle of hydrochloric acid "water" merely because water is the largest by mass component.

          • Re: (Score:2)

            by jdgeorge ( 18767 )

            All our definitions are oriented around our oxygen-based atmosphere.

            FTFY.

            FTFY. One would not call a bottle of hydrochloric acid "water" merely because water is the largest by mass component.

            Quite right. One would instead call a bottle of a hydrochloric acid solution "water-based" because water is the solvent, and also probably the largest component by number of molecules, mass, and volume.

            • Re: (Score:2)

              by khallow ( 566160 )

              One would instead call a bottle of a hydrochloric acid solution "water-based" because water is the solvent, and also probably the largest component by number of molecules, mass, and volume.

              No. They might call it "solution of hydrogen chloride (HCl) in water" [wikipedia.org], but they won't call it "water-based", which by definition means that the foundation of the thing is water, because it isn't.

              When I googled for "water-based", I got page upon page of hits for things like water-based stains and pigments. That is, substances that could be dissolved in a choice of fluids such as water, alcohol, and oils.

              For any life exposed to atmosphere, the key property of Earth's atmosphere is that it has large quan

              • No. They might call it "solution of hydrogen chloride (HCl) in water", but they won't call it "water-based", which by definition means that the foundation of the thing is water, because it isn't.

                When I googled for "water-based", I got page upon page of hits for things like water-based stains and pigments. That is, substances that could be dissolved in a choice of fluids such as water, alcohol, and oils.

                And a hydrochloric acid solution is a substance (anhydrous hydrogen chloride, a gas) dissolved in water.

      • Re:Oxidizer, not fuel (Score:4, Interesting)

        by K. S. Kyosuke ( 729550 ) on Wednesday January 11, 2012 @02:14PM (#38666298)

        In a hydrocarbon atmosphere, you can burn oxygen. All our definitions are oriented around our oxygen-based atmosphere. I'm sure we'd call oxygen 'fuel' if we lived in a hydrocarbon atmosphere and oxygen was the scarcer material.

        Which made a wonderful plot for Isaac Asimov's lovable The Dust of Death [wikipedia.org] :) You can tell the guy was a chemist. ;-)

        • Re: (Score:2)

          by mcgrew ( 92797 ) *

          I could have sworn I'd read Asimov's Mysteries, but I don't remember that story. Guess I'll have to take a trip to the library Saturday. Too bad our corporate-bought copyright extensions have made it so a fifty year old story written by a dead man can't be published in the internet.

          And, Asimov got his PhD in biochemistry. He taught (a little) at Boston University, and also did cancer research there.

      • Re:Oxidizer, not fuel (Score:5, Informative)

        by Megahard ( 1053072 ) on Wednesday January 11, 2012 @02:17PM (#38666338)
        While "oxidation" is lexically derived from oxygen, there's a specific chemical definition for oxidation, namely the loss of electrons. LEO GER is the acronym beginning chemists learn. So while you can play around with the words the chemistry is well-defined. Oxygen is the oxidant because it transfers elections to the reductant or fuel or whatever you want to call it.

        • Thank you!

          In a hydrocarbon atmosphere, you can burn oxygen. All our definitions are oriented around our oxygen-based atmosphere. I'm sure we'd call oxygen 'fuel' if we lived in a hydrocarbon atmosphere and oxygen was the scarcer material.

          Sheesh. Not many chemists here on slashdot, it seems.

        • there's a specific chemical definition for oxidation, namely the loss of electrons. LEO GER is the acronym beginning chemists learn.

          "OIL RIG" for me. Oxidation Is Loss ; Reduction Is Gain.

          What is a Ger, and why would Leo have one? (partial answer : a Mongolian felt hut)

      • Re: (Score:2)

        by mcgrew ( 92797 ) *

        In a hydrocarbon atmosphere, you can burn oxygen. All our definitions are oriented around our oxygen-based atmosphere. I'm sure we'd call oxygen 'fuel' if we lived in a hydrocarbon atmosphere and oxygen was the scarcer material.

        No, it would still be the hydrocarbons oxidising, not the oxygen hydrocarbonizing. Add oxygen and heat to any combustable material and it burns. What can you add hydrocarbons with to make it burn, except oxygen?

        Fire is the result of mixing oxygen with anything flammable. Nothing but

        • no chemistry in you background, I take it. there are plenty of other gases that support combustion, fluorine is one. You could burn fluorine on your hydrocarbon atmosphere planet, or hydrocarbons on a fluorine atmosphere planet. You might be interested to know a rocket with highest specific impulse burns lithium and fluorine. You can make fire with many, many things and not have a molecule of oxygen in sight.
      • As someone points out, oxygen is the oxidant because it supplies the electrons for the reaction (the term "oxidant" is derived from the fact that oxygen was the first chemical that we understood to havethis function). The "fuel" is the chemical that releases energy in the reaction. Hydrocarbons release significantly more energy than oxygen molecules. So, even in a hydrocarbon atmosphere, hydrocarbons would be the fuel as the term is used in English. Of course, if we lived in a hydrocarbon atmosphere we migh
        • The discussion here has the electron donors turned around. The "oxidant" such as oxygen takes the electrons from the reducing agent. Oxygen has 6 electrons in its outer shell and needs only 2 more to have a completely full outer shell, thus it has a strong attraction for those 2 more electrons and takes them from less electropositive elements such as metals. You sound like you know what you are talking about so this is probably just to point out a typo, but I post it to prevent confusion on the thread...

  • Doxygen? (Score:2, Funny)

    by Anonymous Coward
    I read "Tracking down the first doxygen users".

    • As some who wrangles XML on a daily basis, my first thought was the oXygen XML software program (http://www.oxygenxml.com/). Which I have in fact been using since one of the earliest releases.

  • I'm glad someone is looking into this (Score:1)

    by Anonymous Coward

    We cannot afford to have all of the oxygen used.

    To protect the oxygen, there should be a lock on the atmosphere with a good combination. Not some stupid combination that some idiot would use for their luggage.

    • Re: (Score:2, Funny)

      by rubycodez ( 864176 )
      especially since oxygen is a component of the most powerful greenhouse gas on earth, water. And we can't model long term water content, too variable and complicated. We don't really know the contribution of carbon dioxide to the total greenhouse effect (amazing fact), estimated to be 9 to 32%. but the "climatogists" of course wail about the easier one to model.

      • This is totally offtopic, but the thing about water is that it moves in and out of the atmosphere quickly. Water level in the atmosphere is pretty much determined by temperature and perhaps the distribution of exposed ocean area. The result is a massive positive feedback. If something else warms the atmosphere and oceans, the water vapour level rises, adding to the warming, and vice versa. Modern models take full account of this. Historically, water surface temperatures can be determined from the oxygen iso

  • At some levels... (Score:5, Interesting)

    by forkfail ( 228161 ) on Wednesday January 11, 2012 @02:23PM (#38666426)

    ... the human race shares certain critical traits with these little guys.

    Like them, we're creating a cataclysmic event in the biosphere that will probably wipe ourselves out, but allow the next generation of life to thrive.

    Unlike them, we out to be able to mitigate the impact of our presence, but while we're smart enough to see what we are doing, we don't have the fortitude to change our ways.

  • I could be wrong here, but I believe the Oxygen was an SGI box.

    Anyone correct me? ...oh, wait.

  • First Oxygen users... (Score:1)

    by Anonymous Coward

    IMHO it was KDE.

  • ... evolution. That wasn't all that hard, was it?

    Small errors leads to metabolisms that weren't just more resistant to oxygen (remember that it's a nasty poison to anything that's not used to it), but that could acutally use it to generate energy (in fact, more efficiently than by anaerobic metabolism). That opened up whole new habitats. Exponential growth ensues.

Slashdot Top Deals

Don't tell me how hard you work. Tell me how much you get done. -- James J. Ling

Close