The ScienceBlogs Book Club

Chemistry vs. Biology

i-7cce95b26c573f4aa3cee118155325b4-jessica_sachs.jpgCarl, of course, is right in that it wasn’t long ago that biologists scoffed at the idea of bacteria being more than bags of chemistry. Carl’s thoughtful reply to my question included what, for me, is the best distillation of what virus’s “are.” He writes,

“So viruses may or may not be alive, but they are definitely a part of life.”

And as John and several commenters point out, viruses sure as hell evolve!

Still, I find myself in the gotta-have-metabolism camp. To me, that’s the dividing line between chemistry and biology.

As Carl notes in the section “The Shape of Life,” (page 20), “But on their own, genes are dead, their instructions are meaningless.”

I’ve heard viruses described as “escaped genes” … albeit inside nifty protein packages. But as Carl says, MICROCOSM is less about distilling definitions as it is about understanding the rules. In that vein, on page 21, he writes,

“The most obvious thing one notices about E. coli is that one can notice E. coli at all. It is not a hazy cloud of molecules. It is a densely stuffed package with an inside and an outside.”

So life has “boundaries,” an inside and an outside that must be actively maintained.

As cool as bacteriophages look with their lunar lander profile, they are mere snarls of chemicals in and of themselves.

i-b6e21922dd4204654618e31ffca9a44c-Bacteriophage.jpg

Comments

  1. #1 hibob
    June 6, 2008

    If I can bastardize some concepts used when talking about cellular automata and such: trivial reproduction and trivial heredity. How much of the information and how much of the machinery necessary for a thing to reproduce are contained within the thing itself as compared to how much of the complexity is ready made and available within its environment.
    A robot made of legos that reproduces by selecting from various abailable half-robots made of legos and then snapping them together is trivial in both senses. A robot that can sort through a sea of individual lego bits and assemble them accordingly to reproduce and do some maintenance work on itself would get my vote for being a living thing, as would the most complex viruses – you can put me partway into the metabolism camp. A lego robot that can start a family from vats of acrylonitrile and styrene should get anyone’s vote.

  2. #2 John Huey
    June 10, 2008

    We humans have an innate desire to put things into categories and this is a very useful. Defining a category and what belongs and what doesn’t gives insight into what makes a thing and what makes it useful to us. It allows us to put a name on subset of things and easily refer to that subset. However, for many things in the world, our categories are just a human contrivance. Yes, there is a night and there is a day but there is also twilight; there is black and white but there are also shades of gray. We think in categories but nature doesn’t really care what or how we think. It is really not important if a virus is categorized as alive or as non-living – especially, not to the virus. I think that Carl point about rules versus definitions is spot on.

  3. #3 cet
    January 14, 2009

    thanks you good

  4. #4 Hinshaw
    October 18, 2010

    Yes, there is a night and there is a day but there is also twilight; there is black and white but there are also shades of gray.

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