Biological complexity: bacteria R' us (Introduction)

by David Turell , Thursday, September 07, 2017, 15:01 (2415 days ago) @ David Turell

We live in symbiosis with hordes of bacteria everywhere on and in us:

http://nautil.us/issue/52/the-hive/what-the-meadow-teaches-us?utm_source=Nautilus&u...

"It has taken a long time for biology and medicine to arrive at the idea that significant portions of an individual’s own body are foreign to it. Now, however, microbiology in particular is discovering that there is no reposing, solid core within us, but rather a lurking void around which life’s dance unfurls. In the human body, thousands of different players make the meaningful whole possible. We know that our body is colonized by microbes, particularly in the gut, which perform metabolic processes essential to our lives. Within our body, we carry our own, developed ecosystem, without which we could not break down and digest food. There is a reason that biologists call the “biofilm” of microorganisms that cover moist surfaces “bacterial lawns.” With hundreds of species entangled on them—consuming, eliminating, extracting, and synthesizing matter—these bacterial lawns, like the Ligurian pastures, have the characteristic of an undulating meadow in the spring, inside of us. No wonder we have a feeling of recollection on such evenings.

***

"In this age of advanced gene technology, the true abyss of renunciation from which we speak “I” is only now becoming obvious to us. For only a few years, it has been clear that bacteria are completely dominant in a healthy human being: On top of our ten billion body cells, there are one hundred billion microbial cells that play a role in our metabolism. This enormously increases the options for our bodily processes: If we include the microbes’ genes, then we have over 100,000 genes at our disposal, as opposed to just over 20,000. This sort of bacterial aid leads, for example, to children in Papua New Guinea being born with nitrogen-fixing bacteria (like those found in some plants and algae) in their intestinal tissues. This allows them to subsist for years on a plant-based diet without suffering from symptoms of deficiency.

***

"With these symbiotic microbes, our existence joins the ranks of a continuum shared by many other beings that exist outside our bodies. For bacteria are engaged in constant exchange with one another. During times of crisis, they share advantageous genes with one another like children sharing candies. This is why researchers nowadays are speaking less about the various types of bacteria in the world (as they are so transformative) and more about the diversity of their genes and the biological abilities they facilitate. Biologists are regularly stunned by this diversity: The US researcher Norman Pace investigated an ounce of silt from the hot springs of Yellowstone National Park in the 1990s and found more genetic diversity there than scientists had previously assumed to be present in the entire biosphere.

"This diversity is not neatly divided between distinct species or types but is available to all microbes within the context of symbiotic processes of exchange. The late biologist and symbiosis researcher Lynn Margulis believed, for example, that this exchange relationship meant that we should actually speak about all the bacteria on Earth as though they composed a single biological subject—one body swarming with countless cells. Consequently, we who are dominated by a bacterial ecosystem ten times larger than our own body’s cells also belong to the great continuum of life. We are literally, physically, a part of the landscape. The moment we take sustenance from it, we enfold it and its inhabitants into our bodies."

Comment: There is a reason bacteria have survived and been here forever. Look how they join with us and are helpful.