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Discovering microbiology

Microbiology should be part of everyone’s educational experience. European students deserve to know something about the influence of microscopic forms of life on their existence, as it is at least as important as the study of the Roman Empire or the Second World War. Knowledge of viruses should be as prominent in American high school curricula as the origin of the Declaration of Independence. This limited geographic compass reflects the fact that the science of microbiology is a triumph of Western civilization, but the educational significance of the field is a global concern. We cannot understand life without an elementary comprehension of microorganisms.

Appreciation of the microbial world might begin by looking at pond water and pinches of wet soil with a microscope. Precocious children could be encouraged in this fashion at a very early age. Deeper inquiry with science teachers would build a foundation of knowledge for teenagers, before the end of their formal education or the pursuit of a university degree in the humanities.

Earth has always been dominated by microorganisms. Most genetic diversity exists in the form of microbes and if animals and plants were extinguished by cosmic bombardment, biology would reboot from reservoirs of this bounty. The numbers of microbes are staggering. Tens of millions of bacteria live in a crumb of soil. A drop of seawater contains 500,000 bacteria and tens of millions of viruses. The air is filled with microscopic fungal spores, and a hundred trillion bacteria swarm inside the human gut. Every macroscopic organism and every inanimate surface is coated with microbes. They grow around volcanoes and hydrothermal vents. They live in blocks of sea ice, in the deepest oceans, and thrive in ancient sediment on the seafloor. Microbes act as decomposers, recycling the substance of dead organisms. Others are primary producers, turning carbon dioxide into sugars using sunlight or by tapping chemical energy from hydrogen sulfide, ferrous iron, ammonia, and methane.

Bacterial infections are caused by decomposers that survive in living tissues. Airborne bacteria cause diphtheria, pertussis, tuberculosis, and meningitis. Airborne viruses cause influenza, measles, mumps, rubella, chickenpox, and the common cold. Hemorrhagic fevers caused by Ebola viruses are spread by direct contact with infected patients. Diseases transmitted by animal bites include bacterial plague, as the presumed cause of the Black Death, which killed 200 million people in the 14th century. Typhus spread by lice decimated populations of prisoners in concentration camps and refugees during the Second World War. Malaria, carried by mosquitos, massacres half a million people every year.

Contrary to the impression left by this list of infections, relatively few microbes are harmful and we depend on a lifelong cargo of single-celled organisms and viruses. The bacteria in our guts are essential for digesting the plant part of our diet and other bacteria and yeasts are normal occupants of healthy skin. The tightness of our relationship with microbes is illustrated by the finding that human DNA contains 100,000 fragments of genes that came from viruses. We are surprisingly microbial.

Agar kontaminaatio. Photo by Mädi. CC BY-SA 3.0 via Wikimedia Commons
Agar kontaminaatio. Photo by Mädi. CC BY-SA 3.0 via Wikimedia Commons

Missing the opportunity to learn something about microbiology is a mistake. The uninformed are likely to be left with a distorted view of biology in which they miscast themselves as the most important organisms. For example, “Sarah” is a significant manifestation of life from Sarah’s perspective, but her body is not the individual organism that she imagines, and nor, despite her talents, is she a major player in the ecology of the planet. Her interactions with microbes will include a healthy relationship with bacteria in her gut, bouts of influenza and other viral illnesses, and death in old age from an antibiotic-resistant infection. Sarah’s microbiology will continue after death with her decomposition by fungi. In happier times she will become an expert on Milton’s poetry, and delight students by reciting Lycidas through her tears, but she will never know a thing about microbiology. This is a pity. Learning about viruses that bloom in seawater and fungi that sustain rainforests would not have stopped her from falling in love with Milton.

Even brief consideration of microorganisms can be inspiring. A simple magnifying lens transforms the surface of rotting fruit into a hedgerow of glittering stalks topped with jet-black fungal spores. Microscopes take us deeper, to the slow revolution of the bright green globe of the alga Volvox as its beats its way through a drop of pond water. A greater number of microbes are quite dull things to look at and their appreciation requires greater imagination. Considering that our bodies are huge ecosystems supported by trillions of bacteria is a good place to start, and then we might realize that we fade from view against the grander galaxy of life on Earth. The science of microbiology is a marvel for our time.

Featured image credit: BglII-DNA complex By Gwilliams10. Public domain via Wikimedia Commons

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