Perry Marshall, Evolution 2.0, page 100:
Bacteria are the most abundant kind of cells. Most things bacteria do, other kinds of cells do, too. Our knowledge of bacteria forms the foundation for understanding all forms of life. Across the vast kingdoms of life on Earth, bacteria’s linguistic skills are second only to humans’—and in some ways they’re superior. In her TED talk, Dr. Bassler goes on to describe how bacteria send out very small molecules, which form “words” for communication. Each molecule in the chain acts as a letter in the word. Different words form commands or requests, which are understood by their neighbors. Each molecule in the chain acts as a letter in the word (400, 604). Günther Witzany, a German philosopher of biology (407), also explains that bacteria interpret signals based not just on the chemistry but on the context of the situation. Bonnie Bassler also described bacterial communication as linguistic (401). Moreover, bacteria have molecular words for “me,” “you,” “us,” and “them.” They know and describe the difference between themselves and others. They sense how many of their own species and how many of another exist in any population. And they speak multiple languages—a native language for their own species, and foreign languages for other species.
To conduct intraspecies conversations, a bacterium has a special receptor that only accepts molecules from the bacterium they’re conversing with. Dr. Bassler reports that “each molecule fits into its partner receptor and no other. So these are private, secret conversations” (604).* But alongside this, bacteria have a second, generic receptor that emits a different molecule and allows them to communicate with members of different species of bacteria. Dr. Bassler describes this as “bacterial Esperanto,” a language constructed for universal communication. She says bacteria will make decisions based on which species is in the majority and minority of any given population (604). As the paper “Bacterial Linguistic Communication and Social Intelligence” (401) points out, “Bacterial chemical conversations also include assignment of contextual meaning to words and sentences (semantic) and conduction of dialogue (pragmatic)—the fundamental aspects of linguistic communication.”
Bacteria Work in Teams
This capacity for communication makes bacteria social creatures (513), and, as it turns out, democratic ones as well. Dr. Bassler says, “They make chemical words, they recognize those words, and they turn on group behaviors that are only successful when all of the cells participate in unison. We have a fancy name for this; we call it ‘Quorum Sensing.’ They vote with these chemical votes, the vote gets counted, and then everybody responds to the vote” (604). Apparently, the practice of casting votes wasn’t invented by Benjamin Franklin or the Greeks. It was invented by bacteria! I used to think of bacteria as “lone rangers.” But seldom do bacteria float around all by themselves groping for something to eat. They live together in colonies with assigned roles and allegiance to the group. They behave much like ants or bees (502, 513). They greet each other when they meet, they hunt for food together, and they pool their digestive enzymes (522). They prey on other bacterial colonies by surrounding them, digesting them, and splitting the booty (much as human armies do). Martin Dworkin, a preeminent scholar in microbiology at the University of Minnesota (524), said, “In the presence of clumps of prey bacteria, swarms of M. xanthus would frequently turn sharply, head directly for that clump, and then linger there as if at a banquet.” He called it “the microbial wolf-pack effect.” He also showed how bacteria can detect and migrate toward glass beads, but won’t stay and eat as they do after locating a clump of prey bacteria (504). Certain kinds of cyanobacteria called Anabaena divide labor by forming cells called heterocysts. When deprived of nitrogen, they genetically reengineer their genomes to form an enzyme that extracts single nitrogen atoms from the air (507). In other words, division of labor wasn’t invented by Henry Ford or Adam Smith or ancient tribesmen—it was invented by bacteria. When bacteria want to attack you and make you sick, they don’t just hack their way into your system and try to take over. Any one bacterium is far too small and helpless to pull this off.
Rather, they wait until they have built up to a sizable population. They begin signaling each other and when they estimate they’ve reached a critical mass, they launch an organized attack (516). A paper in Nature (514) by Iñigo Martincorena, a fellow at the Sanger Institute, and colleagues reports that mutation rates vary widely from one place in the genome to another. Factors we don’t yet understand influence mutation rate of cells, and mutations maximize the chances of survival. These findings contradict the current popular belief that mutations occur regardless of their ability to help the organism survive. So cells direct their own evolution. They also monitor their genomes to find and fix mistakes. Which brings us to the next surprise.
400 Bassler, B. L. (2002). “Small Talk: Cell-to-Cell Communication in Bacteria.” Cell, 109, 421–424.
401 Ben Jacob, E., Becker, I., Shapira, Y., & Levine, H. (2004). “Bacterial Linguistic Communication and Social Intelligence.” Trends in Microbiology, 12(8 ), 366–372.
407 Witzany, G. (2008). “Bio-Communication of Bacteria and Their Evolutionary Roots in Natural Genome Editing Competences of Viruses.” Open Evolution Journal, 2, 44–54.
502 Chowdhury, D., Nishinari, K., & Schadschneider, A. (2004). “Self-Organized Patterns and Traffic Flow in Colonies of Organisms: From Bacteria and Social Insects to Vertebrates.” Phase Transitions, 77, 601–624.
504 Dworkin, M. (1983). “Tactic Behavior of Myxococcus xanthus.” Journal of Bacteriology, 154, 452–459.
507 Golden, J. W., Robinson, S. J., & Haselkorn, R. (1985). “Rearrangement of Nitrogen Fixation Genes during Heterocyst Differentiation in the Cyanobacterium Anabaena.” Nature, 314, 419–423.
513 Lyon, P. (2007). “From Quorum to Cooperation: Lessons from Bacterial Sociality for Evolutionary Theory.” Studies in History and Philosophy of Biological and Biomedical Sciences, 38, 820–833.
514 Martincorena, I., Seshasayee, A. S. N., & Luscombe, N. M. (2012). “Evidence of Non-Random Mutation Rates Suggests an Evolutionary Risk Management Strategy.” Nature, 485, 95–98.
516 Miller, M. B., & Bassler, B. L. (2001). “Quorum Sensing in Bacteria.” Annual Reviews in Microbiology, 55, 165–199.
522 Shapiro, J. A. (1988). “Bacteria as Multicellular Organisms.” Scientific American, 258, 82–89.
524 Sudo, S. Z., & Dworkin, M. (1973). “Comparative Biology of Prokaryotic Resting Cells.” Advances in Microbial Physiology, 9, 153–224.
604 Bassler, B. L. (2009, February). “[url=http://www.ted.com/talks/bonnie_bassler_on_how bacteria_communicate.html]How Bacteria ‘Talk.’[/url]” TED2009. Retrieved from
The Remarkable Language of Cells
Cell-Cell Communication in Bacteria
Last edited by Admin on Sun Feb 19, 2017 8:55 am; edited 4 times in total