The Data's In: Humans Are Screwing with Evolution
Whether this is good or bad is all a matter of perspective
Hiya!
The word “evoultion” probably triggers the name Charles Darwin in your mind, and for good reason. He was the one to discover it, if you will, changing the course of scientific study from that point on. Darwin proposed that evolution within a species may take hundreds, even millions of years to transpire. Meaning the process is a slow one.
But modern science has shown that evolutionary change doesn’t require immense time. Depending on circumstances, sometimes it occurs within a generation. When considering evolutionary changes within species, the cause of such changes is usually blamed on Nature — survival of the fittest against the elements. However, a recently compiled dataset shows that humans are forcing the natural world to adapt or perish more so than nature is.
Quick Background About Rapid Evolution
Scientists have noticed evolutionary changes within animals have occurred faster than previously believed for over half a century. One of the earliest observations was the peppered moths I told you about a while ago when we talked about urban evolution.
If you don’t remember, in 1955, British researchers published an explosive study about peppered moths. The moths originally had light-colored wings with tiny black specks. But as a result of using Britain's industrial warehouses as their habitat, the moth’s white wings evolved to be completely black, which provided better camouflage with the sooted walls of warehouses.
Over the years, more observations contradict Darwin’s evolution timeline, and in 1999, biologist and professor at McGill University, Andrew Hendry, and professor of Evolutionary Applications at the University of Maine, Michael Kinnison, published a paper that rocked the science community.
The two researchers compiled a database containing examples of known rapid evolution and suggestions about how to better track these changes moving forward. Since then, an additional 5,675 examples of rapid evolution have been added. Now that scientists know that evolution within species doesn’t require vast amounts of time, they want to know just how fast the natural world is changing. Perhaps it’s changing faster than we think, even now. But also, how many of these changes are happening because of us?
Four Offical Findings
I know there’s a lot of finger-wagging going on about the many, many mistakes humanity has made over the years and the now obvious impacts we’ve made on the environment in terms of global warming. But even if we put industrial influences aside, the human species is almost 8 billion strong. With so many of us, our mere existence on the planet is bound to cause ripples of impact throughout the natural world.
For instance, Hendry published another paper in 2021 using the larger dataset — called Phenotypic Rates of Change Evolutionary and Ecological Database, or Proceed— then containing a total of 7,338 examples. In the end, the researchers found four major ways humans contribute to the rapid evolution of animals.
The first shows that “a small absolute difference in rates of change exists between human-disturbed and natural populations.” The dataset shows that the rate of phenotypic changes (or changes in observable traits) of animals is higher in human-populated areas compared to animals that live in nature away from humans. Pollution, specifically, is a significant contributor to the rapid evolution of animals.
Humans don’t only hunt for food. Poaching is also a common reason people kill animals — as trophies or to the harvest parts of the animal, like elephant tusks. And it turns out, as the Proceed database found, that “harvesting by humans results in higher rates of change than other types of disturbance.”
Going back to harvesting elephant tusks, a recent study found that more African female elephants were born without tusks — as in 50 percent more — during a 15-year civil war around Mozambique Gorongosa National Park. Female elephants without tusks passed their genes on to future generations while those with tusks were hunted.
As a result, the number of tuskless elephants has multiplied, and these ones don’t interact with their environment in the same ways. For instance, they can’t toil the soil as much because they can’t dig, and evidence shows they eat different plants than their tuck-possessing counterparts.Animals stray from their initial habitat for all sorts of reasons. Sometimes animals hitch a ride on our boats, planes, and trains while humans travel the globe. Other times, the effects of climate change usher animals to find safer homes. And moving locations means the animal has to adapt to its new environment or perish.
So in a way, it makes sense that “introduced populations have increased rates of [evolutionary] change.” Like how the house sparrows changed in size and color when introduced to North America from Europe to adapt to their new climate. And as you know, often, when a new species is introduced to an environment, it results in the species becoming invasive, which can wreak havoc on an ecosystem.Cope’s rule — the idea that body size increases over time — was a favorite theory for a while. The premise was that a larger body translates to more mating options and higher survival rates.
But Henry and his colleagues found that “body size does not increase through time.” In fact, animals appear to be getting smaller worldwide, and there are several reasons why.For instance, smaller bodies require less energy to function. Plus, larger bodies are better able to retain heat, but as global temperatures rise, it might be more beneficial to be smaller — and thus, cooler. However, humans also play a role in how large or small some species are. Consider fishing. If we only kept the fattest fish of the ones we catch, then only the smaller ones would survive to procreate, leading to ripples that impact that can alter an ecosystem for the worse.
Perspective Shift
There’s one vital aspect to remember in all of this — things don’t just work one way. Yes, humans are to blame for this round of global warming, and our way of living is detrimental to a growing number of species. But we aren’t exempt from the consequences of our actions either. Life is a circle.
The choices we’ve made as a species are forcing us to rapidly adapt to this changing world we created, too. If there’s one thing we’ve learned, it’s that nature will survive — life will survive. But life as we know it… won’t.
Now, this may seem negative, but it doesn’t have to be. Right now, with everything going on in the world, I think our instinct is to catastrophize all of the terrible things to come. But this is also the time when we get to decide who we want to become. Sometimes we need to evolve so we can grow stronger, smarter, and kinder. And rarely do we achieve such feats when we’re comfortable.
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