Natural history, not technology, will dictate our destiny

We do this in our homes, hospitals, yards, farm fields, and even, in some cases, forests when we use antibiotics, pesticides, herbicides, and any other “-cide.” And the effects are always predictable.

Recently, Michael Baym and colleagues from Harvard University constructed a huge Petri plate, or “megaplate”, divided into a series of pillars. Then Baym added agar, which is both a food and a habitat for microbes. The outer column on each side of the megaplate contained agar and nothing more. Moving inwards, each subsequent column was impregnated with antibiotics in increasing concentrations. Baym then released bacteria at both ends of the megaplate to test whether it would develop antibiotic resistance.

Bacteria did not have genes that would confer antibiotic resistance; they entered the megaplate helpless as sheep. And if agar was a pasture for these bacterial “sheep”, the antibiotics were wolves. The experiment mimicked the way we use antibiotics to control disease-causing bacteria in our bodies. He mimicked the way we use herbicides to control weeds on our lawn. He imitated each of the ways we try to preserve nature every time it flows into our lives.

The law of natural selection would predict that as long as genetic variations can occur, through mutation, bacteria could eventually develop resistance to antibiotics. But it can take years or longer. It could take so long for bacteria to run out of food before they develop the ability to spread into columns with antibiotics, columns filled with wolves.

It didn’t take years. It lasted 10 or 12 days.

Baym repeated the experiment over and over again. The same thing happened every time. Bacteria filled the first column and then briefly slowed down, before one and then many vines developed resistance to the next highest concentration of antibiotics. This continued until several vines developed resistance to the highest concentration of antibiotics and poured into the final column, like water over an embankment.

Viewed at a glance, Baym’s experiment is horrific. It’s also beautiful. His horror lies in the speed at which bacteria can go from helpless to indestructible in relation to our power. Its beauty lies in the predictability of experimental results, given the understanding of the laws of natural selection. This predictability allows for two things: it allows us to know when resistance can be expected to develop, whether among bacteria, bedbugs, or some other group of organisms; it also allows us to manage the river of life by making the evolution of resistance less likely. Understanding the laws of natural selection is crucial to human health and well-being and, frankly, to the survival of our species.

There are other biological laws of nature with similar consequences. The Law on the Area of ​​Species regulates how many species live on a particular island or habitat depending on its size. This law allows us to predict where and when species will become extinct, but also where and when they will evolve. The Corridor Law regulates which species will move in the future due to climate change and how. The law of escape describes the ways in which species thrive when they escape their pests and parasites. Escape explains some of the success of humans in relation to other species and how we have managed to achieve such exceptional abundance in relation to other species. The law frames some of the challenges we will face in the coming years when our chances of escape (from pests, parasites, etc.) are less. Niche law determines where species, including humans, can live and where we are likely to be able to live successfully in the future due to climate change.

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