Yet the humble microbes may have a rudimentary form of intelligence, some researchers have found. The claims seem to come as a final exclamation point to a long series of increasingly surprising findings of sophistication among the microbes, including apparent cases of cooperation and even altruism.
This behavior is strikingly versatile, researchers have found in recent years; bacteria can cope with a remarkably wide range of situations by taking appropriate actions for each. For instance, the deadly Pseudomonas aeruginosa can make a living by infecting a wide variety of animal and plant tissues, each of which is a very different type of environment in which to live and find sustenance.
Furthermore, bacteria cooperate: they can group together to take on tasks that would be difficult or impossible for one to handle alone. In a textbook example, millions of individuals of the species Myxococcus xanthus can bunch up to form a “predatory” colony that moves and changes direction collectively toward possible food sources.
Some examples of bacterial cooperation have even led researchers to propose that bacteria exhibit a form of altruism. For instance, some strains of Escherichia coli commit suicide when infected by a virus, thereby protecting their bacterial neighbors from infection.
One example of what such a system could accomplish: a bit of food brushing against the cell could start a series of events that lead inside the cell and activate genes that generate the chemicals that digest the food.
A single bacterium can contain dozens of such systems operating simultaneously for different purposes. And compared to the board game, the cellular systems have additional features that make them more complicated and versatile.
For instance, some of these bacterial contraptions, when set in motion, lead to the formation of extra copies of themselves. These tricks can lead to phenomena with aspects of learning and language.
For example, a shortage of a nutrient in a bacterium’s neighborhood can activate a system that makes the microbe attract the nutrient toward itself more strongly. The system also produces extra copies of itself, researchers have found. Thus if shortage recurs later, the bacterium is better prepared. This is a form of “learning,” Hellingwerf and colleagues wrote in the August, 2001 issue of the Journal of Bacteriology.
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