Wednesday, September 10, 2008

We Are More Bacteria Than We Are Us

And that's a good thing. I think.

I've been giving microorganisms a hard time. I need to show more respect. I owe my life to them. So do cows for that matter, and just about all other living things: 1
"Neither cows nor termites can digest the cellulose of grass and wood without communities of microbes in their guts."

"Certain families of plants (such as the pea family, including peas, beans, and their relatives such as clover and vetch) cannot live in nitrogen-poor soil without the nitrogen-fixing bacteria in their root nodules, and we cannot live without the nitrogen that comes from such plants."

Talk About Symbiosis
"Fully ten percent of our own dry body weight consists of bacteria, some of which, although they are not a congenital part of our bodies, we can't live without."
I may outweigh them, but cell-for-cell, my bacteria outnumber me by a factor of 10:
Humans Carry More Bacterial Cells than Human Ones

According to the authors of Microcosmos, all life is nothing but symbiosis:
"All visible organisms evolved through symbiosis, the coming together that leads to physical interdependence and permanent sharing of cells and bodies."

"The most important examples of symbiosis [are] the chloroplasts (of all plants) and the mitochondria (of all plants and all animals), both of which were formerly independent bacteria."

(Above is a diagram of a mitochondrion I swiped from Wikipedia. Most of our cells contain these; some cells have thousands of them. Our mitochondria came from our mother, they were in the fertilized egg at conception. Mitochondria generate most of our energy (in the form of ATP). This function requires oxygen, and is why we breathe/intake oxygen. Mitochondria are descendants of bacteria and contain their own DNA - different from our own. )

"Let evolution continue a few million years more, for example, and those microorganisms producing vitamin B12 in our intestines may become parts of our own cells."
If a vitamin is any organic substance that our bodies cannot synthesize, but which our bodies cannot live without, then bacteria must be the mother of all vitamins. Or maybe my bacteria (that 10% of my body weight that I voluntarily carry around so they don't have to grow muscles or a skeleton, that, for crying out loud, I breathe for) consider me their primary vitamin.

Gotta run, my bacteria just sent a message to my brain via my gut that they want some food.
1 Microcosmos: Four Billion Years of Microbial Evolution, Lynn Margulis, Dorion Sagan, 1997.

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