"In a series of recent findings, researchers describe bacteria that communicate in sophisticated ways, take concerted action, influence human physiology, alter human thinking and work together to bioengineer the environment".
"But bacteria don’t have sex, they transfer genes among themselves horizontally — and they do a lot of transferring. The primary method most bacteria use is called “conjugation,” a process in which genetic material is transferred between two bacteria that are in contact....... In principle, every bacterium can exchange genes with every other bacterium on the planet. A side effect of this reality: The notion of separate bacterial species is somewhat shaky, although the term is still in use for lack of a better alternative".
"Group behavior has now been demonstrated so widely that many microbiologists view bacteria as multicellular organisms, much of whose activity — from gene swapping to swarming to biofilm construction — is mediated by a wide variety of chemical communications".
'Bacteria use chemicals to talk to each other and to nonbacterial cells as well. These exchanges work much as human language does, says Herbert Levine of the University of California, San Diego’s Center for Theoretical Biological Physics. With colleagues from Tel Aviv University, Levine proposed in the August 2004 Trends in Microbiology that bacteria “maintain linguistic communication,” enabling them to engage in intentional behavior both singly and in groups. In other words, they have “social intelligence.”'
"In 2007, the National Institutes of Health began an ambitious program called the Human Microbiome Project, which aims to take a census of all the microorganisms that normally live in and on the human body. Most of these live in the digestive tract, but researchers have also discovered unique populations adapted to the inside of the elbow and the back of the knee. Even the left and right hands have their own distinct biota, and the microbiomes of men and women differ. The import of this distribution of microorganisms is unclear, but its existence reinforces the notion that humans should start thinking of themselves as ecosystems, rather than discrete individuals".
"Researchers have found several reasons to believe that bacteria affect the mental health of humans. For one thing, bacteria produce some of the same types of neurotransmitters that regulate the function of the human brain. The human intestine contains a network of neurons, and the gut network routinely communicates with the brain. Gut bacteria affect that communication. “The bugs are talking to each other, and they’re talking to their host, and their host talks back,” Young says. The phrase “gut feeling” is probably, literally true".
"Even more intriguingly, there have long been hints that some bacteria, including Bifidobacteria commonly found in yogurt, can improve mood."
"Bacteria can distinguish “self” from “other,” and between their relatives and strangers; they can sense how big a space they’re in; they can move as a unit; they can produce a wide variety of signaling compounds, including at least one human neurotransmitter; they can also engage in numerous mutually beneficial relationships with their host’s cells. Even more impressive, some bacteria, such as Myxococcus xanthus, practice predation in packs, swarming as a group over prey microbes such as E. coli and dissolving their cell walls".
"And today the idea of thinking microbes is gaining ground. Marc van Duijn and colleagues at the University of Groningen in The Netherlands point out in the June 2006 issue of Adaptive Behavior that the presence of “the basic processes of cognition, such as perception, memory and action” in bacteria can now be “plausibly defended.” And bacteria that have antibiotic-resistance genes advertise the fact, attracting other bacteria shopping for those genes; the latter then emit pheromones to signal their willingness to close the deal. These phenomena, Herbert Levine’s group argues, reveal a capacity for language long considered unique to humans".
'So maybe bacteria are just computers, which so far, despite humans’ unending fantasies of conscious machines, aren’t yet really thinking. But University of Chicago microbial geneticist James Shapiro believes they come extremely close. He sees bacteria as consummate practitioners of information management, plus a bit more. They “have ways of acquiring information both from the outside and the inside,” he says, “and they can do appropriate things on the basis of that information. So they must have some way to compute the proper outcome.” It is these “sophisticated information processing capacities,” Shapiro wrote in the paper “Bacteria Are Small but not Stupid,” that represent “another step away from the anthropocentric view of the universe. … Our status as the only sentient beings on the planet is dissolving as we learn more about how smart even the smallest living cells can be.”'
"Is some nonhuman software organizing the teamwork of all those nonhuman semi-smart robots, aka bacteria? For this would be the truly radical argument: that bacteria — demonstrably integrated deeply and broadly into the entire planet, shaping its geochemistry, creating substrates and chemical processes that support the development of complex organic molecules, regulating the cycling of energy and nutrients both in “higher” organisms and their environments — constitute a kind of distributed awareness encompassing the whole planet. That not only are bacteria in a given local environment busy texting each other like mad, but the entire planet may consist of a giant Microbial World Wide Web."
"The grand story of human exceptionalism — the idea that humans are separate from and superior to everything else in the biosphere — has taken a terminal blow from the new knowledge about bacteria."