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Biotech Science

One Variety of Sea Slugs Cuts Out the Energy Middleman 232

dragonturtle69 writes with this story, short on details but interesting: "These sea slugs, Elysia chlorotica, have evolved the ability to gain energy via photosynthesis. Forget about genetic modifications for sports enhancements. I want to be able to never need to eat again — or do I?"
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One Variety of Sea Slugs Cuts Out the Energy Middleman

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  • by bigattichouse ( 527527 ) on Wednesday January 13, 2010 @02:06PM (#30754316) Homepage

    That was my totally favorite upgrade in Mail Order Monsters - recharge from the sub!

  • eating (Score:5, Insightful)

    by mcgrew ( 92797 ) * on Wednesday January 13, 2010 @02:06PM (#30754320) Homepage Journal

    I want to be able to never need to eat again -- or do I?

    I'l like the ability to never HAVE to eat again, but I wouldn't want to lose the ability to eat at all. Eating is enjoyable. One would hope that you could control the photosynthesis to keep from getting too fat, though.

    • Re:eating (Score:5, Insightful)

      by confused one ( 671304 ) on Wednesday January 13, 2010 @02:23PM (#30754618)
      Slugs aren't very energetic. It's doubtful that photosynthesis alone will provide the energy necessary to power your body and that meat based computer in your head. You would still need to ingest a fair amount of food, in order to extract the concentrated energy contained in it.
      • Re: (Score:3, Funny)

        by Intron ( 870560 )

        Slugs aren't very energetic. It's doubtful that photosynthesis alone will provide the energy necessary to power your body and that meat based computer in your head.

        So this would work for my boss, then.

      • Re:eating (Score:5, Informative)

        by sarahbau ( 692647 ) on Wednesday January 13, 2010 @02:45PM (#30754952)

        I just did a few quick calculations. Assuming humans have 2 square meters of skin, and stood naked in direct sunlight in the best conditions for 8 hours per day, and assuming 5% efficiency for photosynthesis, we would only get enough energy to provide for 11 hours of sleep (250 BTU/hr), 7 hours of sitting still (400 BTU), 4 hours of light work (650 BTU) or 1 hour of heavy work (2400 BTU). We'd still probably need to consume 2/3 or so of our normal caloric intake from food.

        Sources:
        http://www.solarexpert.com/Heat-theory.html [solarexpert.com]
        http://hypertextbook.com/facts/2001/IgorFridman.shtml [hypertextbook.com]
        http://www.answerbag.com/q_view/514275 [answerbag.com]
        http://www.ccmr.cornell.edu/education/ask/index.html?quid=1021 [cornell.edu]

        • Especially in Third world countries where there is plenty of sun, not much food and not much to do other than subsistence living,. At least it would be enough to get a lot of starving humans through the dry famine months that they get in thrid world countries near the equator.

          Sure their skin would be green, but that beats starving to death.

        • That covers my needs. I'm in!

        • Wait... You're saying there's a reason plants don't move?
        • Re: (Score:3, Informative)

          by jschen ( 1249578 )

          and assuming 5% efficiency for photosynthesis

          Interestingly, this estimate is right around the theoretical maximal efficiency of photosynthesis. As outlined in Current Opinion in Biotechnology 2008, vol. 19, pp. 153-159 (sorry, subscription only), the maximum theoretical efficiency of C3 photosynthesis is a mere 4.6%. C4 photosynthesis has a bit higher potential at 6.0%.

          We can't even reach these efficiencies in plants (best for crops in a growing season is 2.4% for C3 or 3.7% for C4; see above reference), so sarahbau is right in saying that the amount

    • I seriously doubt that we have enough surface area to replace eating with photosynthesis. We would also continue to need nutritional input.
      • I seriously doubt that we have enough surface area to replace eating with photosynthesis.

        That can be remedied. Who doesn't want enormous green wings sprouting out of their back?

    • One would hope that you could control the photosynthesis to keep from getting too fat, though.

      Sunscreen.
      SPF: Diet

    • by Z00L00K ( 682162 )

      You will probably need to eat something to gain minerals, but eating for energy can be restricted.

    • by vlm ( 69642 )

      One would hope that you could control the photosynthesis to keep from getting too fat, though.

      Wear variable amount of clothes.

      Strange side effect -> women in tiny bikinis would be fat, women in the cover it all up wetsuit like one pieces would be skinny.

  • by Rei ( 128717 ) on Wednesday January 13, 2010 @02:09PM (#30754362) Homepage

    Any other questions that could be easily answered by playing Starcraft?

  • No you don't (Score:3, Insightful)

    by kiick ( 102190 ) on Wednesday January 13, 2010 @02:10PM (#30754368)

    As everybody knows....
    It's not easy being green.

  • I want the reverse. (Score:5, Interesting)

    by jeffb (2.718) ( 1189693 ) on Wednesday January 13, 2010 @02:13PM (#30754424)

    I want to be able to consume as many extra calories as I like, and then radiate the excess as visible light, with radiant area, spectrum and direction under my conscious control.

    Or, at least, I'd like to be able to metabolize my food and store excess energy as electric charge, easily transferred to whatever devices are handy.

    • i think i like this idea.
    • by Xtravar ( 725372 )

      It seems you've been playing too much inFamous. Now glucose powered devices that run off your blood stream, that seems more feasible.

    • by ArsonSmith ( 13997 ) on Wednesday January 13, 2010 @02:40PM (#30754890) Journal

      This would be awesome. having a + and - poll could give men's nipples a purpose.

    • by Kratisto ( 1080113 ) on Wednesday January 13, 2010 @02:42PM (#30754912)
      If you can make that light coherent and focused, you can be some sort of super hero. Laser Pointer Assisted Presentation Man! Is it a CEO? Is it a college professor? No! It's Laser Pointer Man! Boring wrongdoers into soporific oblivion at the speed of light! Taunting cats in his free time...
    • by TheLink ( 130905 )

      Modern man in effect eats a fair bit of oil and coal. It allows them to generate light, travel great distances fast etc.My car consumes about as much in $$$ terms as I do per month.

      But yeah, being a superhuman could be fun :).

      What you might want in addition to your lightbeams and electric zapping superpowers is the ability to use energy from an external power source to power your anaerobic metabolic modes = e.g. you can sprint and not get tired[1] till you run out of energy from that power source.

      While powe

    • Well, the problem would be that you then would also be very hot. And not in the good sense. More in the “spontaneous combustion” sense. ;)

      But I agree that a way to not use unnecessary calories without an effort would be great. Decadent beyond belief. But great. ;)

      You already have metabolized it into a storage. That’s your fat. You just never use it up. I once calculated, that if released all at once, the fat in my body would give enough power to run a flux compensator for 0.88 seconds. No

    • That's so much better than my idea of a bicycle powered TV. With your method, you could power the TV directly, just by eating.

    • It'd be awesome up to the point where you realize that 7 billion people eating everything in sight drained the global food supply. Then you'll be wishing you had that photosynthesis.
    • I want to be able to consume as many extra calories as I like, and then radiate the excess as visible light

      I want to be able to radiate invisible light [wikipedia.org], perhaps also radiate cold heat and dry water.

      • Light is electromagnetic radiation, particularly radiation of a wavelength that is visible to the human eye

        Is not the same as:

        Light is electromagnetic radiation of a wavelength that is visible to the human eye

      • If you would be so kind as to go soak your head in a large reservoir of liquid nitrogen for a few hours, you'll have your opportunity. Your head will be radiating light/heat at a blackbody temperature around 77K, which is (a) invisible and (b) cold. For the "dry water" part, well, frozen tissue at 77K really isn't very "wet" at all, except in the chemical sense.

    • Just eat some lava, and heat yourself up to a >1000K
      You'll radiate as visible light!

    • Re: (Score:2, Funny)

      I am intrigued by your ideas, and wish to subscribe to your newsletter.
    • by lewp ( 95638 )

      Personally, when I feel so stuffed I can't eat any more, I just use the restroom. Then I can eat more.

    • by adisakp ( 705706 )

      Or, at least, I'd like to be able to metabolize my food and store excess energy as electric charge, easily transferred to whatever devices are handy.

      Hook an excercise bike up to a generator which is connected to a battery. Satisfies your requirements other than the "easy" part.

      • Well played. In fact, once you've got the charge in the battery, I'd argue that it is "easily transferred to whatever devices are handy".

        It would be nice to have a more direct metabolic conversion, though, preferably one that doesn't generate quite so much sweat, fatigue, and boredom.

    • Just try not to get Wonder Boy killed off will ya?

    • Ugh. I don't want to need welding goggles just to drive by McDonalds.

  • Photosynthesize! (Score:4, Interesting)

    by The Yuckinator ( 898499 ) on Wednesday January 13, 2010 @02:13PM (#30754432)

    Once you've "eaten enough algae to steal the necessary chloroplasts", you'll be good to go!

    I would happily endure eating algae for X days/weeks/months in order to get photosynthesis going in my body. I realize that I'd have to start going outside, but it sounds like a fair trade off to me.

  • by Taibhsear ( 1286214 ) on Wednesday January 13, 2010 @02:20PM (#30754570)

    In a normal plant cell is the chlorophyll produces by the cell and then shuttled to the chloroplast to be used or does the chloroplast itself produce the pigment within it's own membrane? If the latter, I would imagine this gene in the slug is redundant as the creature has to eat algae for the chloroplasts anyways.

    • by reverseengineer ( 580922 ) on Wednesday January 13, 2010 @03:05PM (#30755240)
      Chloroplasts, just as with mitochondria, have a small DNA genome of their own. Due to the endosymbiotic relationship that has formed between chloroplasts and their photosynthetic hosts, chloroplasts have found it convenient to offload the majority of their genes to the nucleus. It is estimated that about 90% of the genes necessary for photosynthesis are nuclear, with the rest in chloroplasts, so these sea slugs appear to have acquired the nuclear genes, but not the chloroplast genes.

      Chlorophyll itself is made in the cytoplasm, and actually requires relatively few new genes for an animal to be able to produce it, since the complicated steps of its biosynthesis are identical to the heme structures it is already able to make. The real difficulty, and one that this sea slug seems to have been able to surmount according to the Wikipedia page, is the production of the "oxygen-evolving complex," a metalloenzyme with a manganese-calcium core which transfers absorbed energy to a bound water molecule to break it into electrons, protons, and molecular oxygen. Heterotrophic organisms don't produce anything like it.
  • by gr8_phk ( 621180 ) on Wednesday January 13, 2010 @02:33PM (#30754788)
    The article seems to indicate that the genes to produce chlorophyll can be passed on to offspring. But then:

    The slugs accomplishment is quite a feat, and scientists aren't yet sure how the animals actually appropriate the genes they need.

    Wouldn't that be a fluke that only needed to happen once? They do point out that the animals also have to get chloroplasts by eating plant material (these are not passed on to offspring), so perhaps they meant to say they aren't sure how they appropriate the chloroplasts. I would agree that's a really good question.

    • Re: (Score:3, Insightful)

      by osu-neko ( 2604 )

      Wouldn't that be a fluke that only needed to happen once?

      Calling it a "fluke" is not an explanation. The thing about scientists is, they like to find out how these "flukes" happen.

  • by Guppy ( 12314 ) on Wednesday January 13, 2010 @02:35PM (#30754820)

    Some species of Sea Slugs have another similar interesting ability -- to adsorb and host nematocysts (stinging cells) from jellyfish and hydrozoans they've eaten, and use them for their own defense. The mechanism is substantially different (foreign cells are sequestered in specialized sacs, compared to the intracellular hosting of an organelle) though.

    http://en.wikipedia.org/wiki/Glaucus_atlanticus [wikipedia.org]

  • by Locke2005 ( 849178 ) on Wednesday January 13, 2010 @02:41PM (#30754898)
    Couldn't you just form an symbiotic relationship with algae or photoplankton, allowing them to live inside you for protection in return for using them for energy? Aren't there already animals that do this?
    • We already do almost that (except the inside body part). It's called agriculture :)

    • Of course the problem with photosynthesis is it doesn't produce energy that quickly so it'd probably be used by slow moving animals like that. Here's a link http://www.nhm.ku.edu/inverts/ebooks/intro.html [ku.edu]
    • Re: (Score:2, Informative)

      by osu-neko ( 2604 )

      Couldn't you just form an symbiotic relationship with algae or photoplankton, allowing them to live inside you for protection in return for using them for energy? Aren't there already animals that do this?

      There are. That process is well understood, and thus, not all that interesting to scientists. What this slug does in addition to that is novel and thus interesting.

    • Yes, corals [wikipedia.org] do this. Contrary to popular belief, corals are not plants but animals living in a symbiotic relationship with algae.
  • Building and repairing too. And well, there are those that enjoy the taste of some food. Anyway, having an extra source of energy won't hurt, you dont always need to be building and repairing, or at least could do it in a less urgent way than for getting the energy needed to live.
  • Is this actual, observed evolution?
    Is this the proof creationists are always demanding?

    • No. Studying something unique in the animal kingdom for 20 years does not make it evidence for anything. The slug is able to build chlorophyl from borrowed chloroplasts -- something no other animal has done. How long it's been doing that, we don't know. It's something cool and something that biological researchers can observe and attempt to understand outside of the pseudoscientific holy war of the church of evolutionism vs. all other religions. Dragging evolutionism vs creationism into this will only
    • Re: (Score:2, Informative)

      by osu-neko ( 2604 )

      Is this actual, observed evolution? Is this the proof creationists are always demanding?

      Yes and no. It is one of thousands of examples of observed evolution, and the process is already well proved. This will not stop the demands, however, since the demands are not made in good faith...

    • Re: (Score:3, Funny)

      by jameskojiro ( 705701 )

      No, God just invented them with the ability to do this to confuse us all. God loves gettin' his jollies off keep mankind eternally confused.

  • by JoshDM ( 741866 ) on Wednesday January 13, 2010 @03:13PM (#30755388) Homepage Journal
    FTA: "The sneaky slugs seem to have stolen the genes that enable this skill from algae that they've eaten."

    I'm gonna go find and chow down on some ninjas right now, so I gain Real Ultimate Power!!
  • by Anonymous Coward on Wednesday January 13, 2010 @03:13PM (#30755392)

    Slugs have been around for millions of years!

  • I want to emit light. at will. So I don't need a flashlight, or could get a job as an organic tanning booth and loose weight at the same time. Or, dare I say, sparkle when outdoors.

  • if you take time to think how much of our time passes while doing mandatory eating, strenous digesting and dealing with the excrement and crapping it, you would be appalled.

    in addition, a good deal of energy we take in by eating is spent on digesting the food itself. check your body in an atlas. almost 1/3 of the internal organs are allocated to digestion.

    imagine cutting out the middleman.

  • Eating the brains of our slain foes is probably as close as we'll ever get to a Highlander quickening. These slugs are already workin' their way up the ladder, and they just might be coming for YOUR brains in a few years....

  • I too think that ABC Family are a bunch of sea slugs for having canceled The Middleman.

  • by lpaul55 ( 137990 ) * on Wednesday January 13, 2010 @10:30PM (#30760438) Homepage Journal

    Roger Ebert recently wrote about his life after surgery. He can no longer take anything by mouth. I can't imagine life without taste, but he lives it.

Keep up the good work! But please don't ask me to help.

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