Since emerging on the world stage, the virus that causes COVID-19 has infected hundreds of millions, killed millions, and disrupted society in ways that will branch out for decades. COVID-19 is a story of politics, culture, and medicine, but underneath it all, it’s also an extraordinary story of evolution. Charles Darwin imagined that evolution by natural selection happened too slowly to be observed in action. It was, he thought, a process that took decades, centuries, or, more often, millennia.
COVID-19 reminds us that evolution can happen in weeks, days or even hours. It occurs on the body of every infected person. On our bodies, the strains of the virus that causes COVID-19 have evolved in relation to the human immune system, vaccines, and even the need to travel from individual to individual. In this regard, the Omicron variant is as powerful a testament to the force of natural selection as blue whales, mushroom-farming ants, or finches in the Galapagos Islands.
If he were alive today, Charles Darwin would have been, above all, terrified of contracting COVID-19. He was constantly worried about his health (and, of course, at 212, he would have been right to worry). But he would also marvel at the speed of evolution of the virus. Over the past decade, biologists have discovered that evolution is happening all around us.
Learn more about the evolution:
The rate of evolution of new bloodlines and forms can actually be accelerated on our bodies, in our homes, around our cities, and on our farms. In my new book, The natural history of the future, I consider the rules of this acceleration. Here are some of my favorite examples of evolution seen right now, examples in which the story will be different a decade from now precisely because these species continue to evolve.
Species that evolve with the heat of cities
We make cities warm. Sidewalks and buildings store heat and release it under our feet. In some cities, the blocks with the most cement and the least green life are already as hot as the surrounding countryside should be in 2100. Some species are evolving to cope with this heat. In the hottest parts of Cleveland, Ohio, urban ants living inside tiny acorns have evolved the ability to tolerate more extreme heat than their country cousins may.
Natural selection favors heavier tree seeds
In Montpellier, France, the future unfolds on busy streets. Even in the most urban areas of Montpellier, one finds the fuzzy yellow flowers of the hawk’s-beard plant (Crepis sancta). In natural habitats, hawksbeard tends to produce lighter seeds that are able to catch the wind and move to new patches. But in Montpellier, hawks often live in tree pits. In these tree pits, the next habitat patch is likely to be far away. To deal with this, urban hawk beard plants with heavier seeds that don’t fly are favored by natural selection; their more chubby seeds are more likely to land in the same tree pit and survive.
New York Rats need a new meeting space
In Manhattan, inner city rats and inner city rats have stopped meeting in the city center (perhaps because the number of overnight residents and therefore food is slightly lower in a downtown strip). Without meeting, rats do not mate or share genes. And so they diverge, embarking on their own independent evolutionary trajectories.
The pigeon population is to separate
Pigeon populations also separate. The pigeons from Boston, for example, diverge from those from New York. Eventually, where towns stay separate, each town can have its own unique pigeon. It’s not just pigeons. Lice on pigeons evolve. Pigeons have two types of lice. A kind rides from pigeon to pigeon on tiny flies (really); they are likely to evolve more slowly because their wanderings keep their genes moving from here to there and from there to here. The other type of pigeon louse passes from the mother pigeon to the baby pigeon.
Foxes in cities, for reasons that aren’t entirely clear, have evolving faces that look more like those of dogs. Keep an eye out for their shorter muzzles and weaker jaws. And stay tuned for more studies on the reasons for this change.
Lizards with longer toe pads
In Puerto Rico, urban Anolis lizards have evolved longer limbs and “more eye-catching” toe pads which together allow them to cling better to buildings and other man-made structures.
An evolving taste for starch
For most mammals, starch has no taste, so there is no reward for seeking it. Humans, however, have evolved extra copies of amylase genes. These genes produce the enzyme amylase in the human mouth which begins to break down starch into simple sugars; these sugars are then sweetened. Clearly, humans from agricultural societies that ate more starch were more likely to survive. We now know that many of these mammals that rely on garbage and human donations also have undergone the same evolutionary transition.
Cockroaches adapt to avoid bait
Cockroach bait sounded like a revolution. Rather than spraying pesticides around a house, the baits allowed cockroaches to be attracted to the pesticide. The baits contained glucose which attracted cockroaches until widespread use of bait inadvertently triggered evolutionary changes in the brains of German cockroaches. Some populations of German cockroaches have evolved to perceive the taste of glucose as bitter and avoiding bait.
Your refrigerator is alive
In your refrigerator, bacteria are alive and actively metabolizing in all of your stored foods, but especially in fermented foods such as yogurts and cheeses. Even within an individual block of cheese or pot of yoghurt, bacteria can undergo large evolutionary changes even in just a few days. But the most important evolutionary changes occur in the viruses that attack the bacteria that produce cheese and yogurt.
The Bacteria Inside You Are Constantly Evolving
Even closer to home, in your belly, bacteriophages evolve according to the modifications of the bacterium on which you depend for your survival. Each species of bacteria in your gut seems to have one, if not more, specialized types of bacteriophages attacking it. These bacteriophages evolve so rapidly that if twin babies were inoculated with the same bacteria and bacteriophage species at birth, one baby’s bacteriophages would be recognizable as separate species from the other.
The truth is that many of these changes are not only observable in real time, they are also predictable. Evolutionary biologists watch their predictions, made by studying the past looming around them in their daily lives. They see tests of their predictions in gutters, on sidewalks, and even in their fridges. And they just started looking.
Consider the reality that when you breathe in, you breathe in hundreds (and often thousands) of species. Most of these species have not yet been studied. They all evolve. Some fast and some slow. Inhale. Exhale. This is the relentless course of natural selection, the endless story of evolution, a story that began billions of years ago and continues wherever there is life.
A natural history of the future by Robb Dunn is out now (£14.99, Hachette)