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Are Human Beings Organisms Or Living Ecosystems?

Posted by Soulskill on from the little-of-column-a,-little-of-column-b dept.

Hugh Pickens writes "Every human body harbors about 100 trillion bacterial cells, outnumbering human cells 10 to one. There's been a growing consensus among scientists that bacteria are not simply random squatters, but organized communities that evolve with us and are passed down from generation to generation. 'Human beings are not really individuals; they're communities of organisms,' says microbiologist Margaret McFall-Ngai. 'This could be the basis of a whole new way of looking at disease.' Recently, for example, evidence has surfaced that obesity may well include a microbial component. Jeffrey Gordon's lab at the Washington University School of Medicine in St. Louis published findings that lean and obese twins — whether identical or fraternal — harbor strikingly different bacterial communities that are not just helping to process food directly; they actually influence whether that energy is ultimately stored as fat in the body. Last year, the National Institutes of Health launched the Human Microbiome Project to characterize the role of microbes in the human body, a formal recognition of bacteria's far-reaching influence, including their contributions to human health and certain illnesses. William Karasov, a physiologist and ecologist at University of Wisconsin-Madison, believes that the consequences of this new approach will be profound. 'We've all been trained to think of ourselves as human,' says Karasov, adding that bacteria have usually been considered only as the source of infections, or as something benign living in the body. Now, Karasov says, it appears 'we are so interconnected with our microbes that anything studied before could have a microbial component that we hadn't thought about.'"

7 of 397 comments (clear)

  1. Obesity & Bacteria by plague3106 · · Score: 5, Interesting

    So the bacteria in the twins is different... why is it worded in such a way as to imply the different bacteria is the reason that one is obese and the other isn't, instead of the type of bacteria changed because being obese (and the eating that goes along with it) favor one type over the other.

    1. Re:Obesity & Bacteria by Anonymous Coward · · Score: 5, Interesting

      I've been struggling with obesity for some time now. I eat more healthy than many of my slimmer friends and I often work out more, yet I still weigh considerably more.

      Does this mean that it's impossible for me to loose weight? No way, I have been exercising more and eating better and I know have been shedding more pounds. It's just frustrating to watch them eat more junk and not work out at all, and remain slim, where as I would balloon :|

    2. Re:Obesity & Bacteria by DriedClexler · · Score: 4, Interesting

      I don't know what your point was, but this wouldn't refute genetic determinism; it just says that the genes determining "you" include those of bacteria.

      Incidentally, I don't understand what's so new about this insight. I read a book published in 1995, Darwin's Dangerous Idea by Daniel Dennett (a philosopher rather than a biologist so he was only drawing on what was long-established consensus at the time). It described the view of the body as an ecosystem and suggested that human cells were like "altruistic versions of ant cells" since human cells share even more genetic material (100%) with their neighbors.

      --
      Information theory is life. The rest is just the KL divergence.
    3. Re:Obesity & Bacteria by Pjerky · · Score: 4, Interesting

      Your post is highly misleading and presumptuous. First of all there is a lot more to it than eat X amount of calories and you will lose weight. Physical activity, of course, plays a role. But then there is also the chemical and metabolic response of the body that also has a tremendous influence as well as timing of when you eat, when you go to bed, how much sleep you get, the chemical effects of the food you eat on your body, and a whole host of other things.

      Let me give you an example. Right after most people eat their heart rate and metabolic response drops, often they feel a bit less energetic and alert, and their body switches "modes" in how it burns energy, usually burning less and storing more at this point. However my body is different. When I eat my heart rate and metabolic response increases by anywhere from 20 beats per minute to 60 bpm. I get warmer, become more alert and more energized.

      During that period immediately following eating I can usually exercise longer than other times and not feel tired at all. But ironically this doesn't mean that I am skinny. In fact I am obese. My body stores energy from everything and is VERY efficient at squeezing every last bit of energy and nutrition out of food. My best friend by contrast is skinny and would collapse if he at the same amount of calories that I do (I currently average between 1500 - 2000 calories a day). He has to eat at least twice as much as I do just to function. His digestive system is highly inefficient and his heart rate and metabolic response drops off after eating.

      Now another thing that research has shown is that if you spread out your calories across 5 meals in a day you will burn more calories and store less than when eating the same number of calories in 3 or less meals in a day. This technique is used by many to help them lose weight to great effect.

      So giving some blanket statements about getting fat or thin just don't apply. It really varies from person to person as to what things effect what people.

      --
      The Mind Is Speculative and Interpretive. So speculate all you want and interpret this 00101101 01001110!
  2. Viruses, too by forrie · · Score: 5, Interesting

    A recent program on NatGeo (Explorer?) hypothesizes that viruses are also a key part of human evolution.

    The "junk DNA" that we all have is likely the result of viruses.

    They've also discovered that viruses in the wild actually quite easily jump from species to species, too.

    In one of the experiments, they found a large amount of a certain virus in the womb of a sheep during pregnancy. When inoculated against the virus, the pregnancy would not complete.

    Very interesting theory.

  3. 100 trillion mitochrondia too by peter303 · · Score: 3, Interesting

    A billion or so years ago the forerunners of multicellular life made a devils pack with oxygen burning mitochrondia, thereby increasing their metabolic energy an order of magnitude over less powerful energy subsystems like lactosis and sulfur oxidation. This basically created animals with the power of locomotion. So I sometimes visualize a shadow "power body" inside my primary body of these teaming mitochrondia generating 90% of my power. This is not dissimular to prana in yoga, chi in daoism and the force in star wars. Not that I'm going to turn blue and start shooting electric bolts out of my fingers any time soon.

  4. DNA shot gun analysis is a powerful analysis tool by peter303 · · Score: 3, Interesting

    Its very difficult to separate out the different kinds of bacteria, identify them visually and cultivate them. Shotgun DNA originated by Craig Venter helps tell how many kinds of different bacteria species there are growing in different parts of the body. There are more kinds than people expected. Different locations of the body, gut, airways, skin creases, etc. have different ecologies.

    Shotgun DNA is a "similar, but different approach". They first map every piece of DNA in every microbe (but in pieces). Then they look for a few key sequences somewhat conserved among species, and note minor differences. This distribution of differences gives a count of species and relatives amounts of each. Later on they may connect these to actual microbe types.