It’s well known that humans have had a huge impact on the world’s biodiversity, with some suggesting that we have precipitated the sixth major extinction event in the Earth’s history. This may also be the worst sin perpetrated in Earth’s history. And it will only be accelerated and perpetuated via climate change. Shitty job, us.
A lesser known phenomenon occurring via humans is that we have changed the path of evolution for countless critters. There is the textbook example of the peppered moth, which evolved darker strains after the industrial revolution, resulting in better camouflage on polluted surfaces. Newer studies have found that swallows that spend more time around highways have evolved shorter wings, the better to dodge and dart around traffic. A new study, also with moths, finds that city variants of ermine moths are less attracted to light than their bumpkin cousins – thus avoiding the pitfalls of porch lights.
A few dozen millennia ago, wolves that capitalized on leftovers from human camps started developing traits that endeared them to humans – and bingo bango, we got chihuahuas.* After the hunter-gatherers and their dogs started planting stuff and settling down, we started to manipulate plant and animal life to an even greater degree. Did you know that cabbage, broccoli, cauliflower, kale, and Brussels sprouts are the same species, Brassica oleracea? Or, rather, they were all cultivated from that wild plant. Carrots used to be mostly purple. Corn cobs used to look a lot more like grass stalks before humans got their hands on them.
Way before Darwin and Mendel figured out what the hell was going on, humans were intentionally changing evolution. And by changing our environment, as in the moth and swallow examples above, we’ve also made unintentional alterations to the fabric of our world. Unlike the moth and swallow examples, some of these alterations will have lasting negative repercussions.
As a small example, I was in my yard yesterday ostensibly destroying some dandelions (sans chemicals), and it occurred to me that these little em-effers are probably evolving adaptations to work around human attempts to eradicate them. I noticed that some of the dandelion flowers grow very close to the ground – is this an adaptation brought about by the dreaded lawnmower? What other ways have they evolved to continue to blight our attempts at perfect green carpets of grass?
On a larger scale (and with more than just aesthetic implications), pesticides are leading to resistant pests, which leads to increased pesticide use and new chemicals – great for Monsanto, shitty for the rest of us.
On a microscale, antibiotic overuse results in super bacteria evolving resistance, which leads to an arms race – great for big pharmaceutical companies, shitty for us. Antibiotics have also, in a sense, changed human evolution in that they have changed our microbiomes, which is partly responsible for a number of modern ailments.
Speaking of which, modern medicine has changed the course of human evolution in other ways. One side effect of the amazing advances of modern medicine is allowing many genes that used to be weeded out through natural selection to remain in the gene pool. Eventually, this problem may be solved via gene therapy, which will ultimately be a form of human-directed evolution (but that’s a story for another post).
In a sense, we are GMO’ing (GM’ing is probably more accurate) ourselves and the world – or the world is GM’ing itself, in an adapt-to-human-changes-or-die scenario. This has, of course, been part of the game since the incipient primordial soup, when microorganisms reacted and evolved to adapt to changes wrought by other microorganisms. The relationship between flowering plants and insects is one of the most fascinating examples of this. Consider the bee orchid, which, in what could be considered trans-species sexual selection, mimics a female solitary bee, inducing male bees to pseudocopulate** with the flower, thus transferring pollen (if they’d stop fucking flowers, maybe they wouldn’t be such solitary bees).
But never has the course of evolution been so affected by one species: humans. Human-caused extinction has to be up there as one of our worst irredeemable acts, but we shouldn’t overlook the other ways in which we’re altering our big blue marble.
*One of my favorite disses on the creationist dupes was in the movie “Jesus Camp,” when the mom says “Creationism… it’s the only possible answer to all the questions” and the camera briefly pans to her chihuahua-ish wolf (1:51 in this clip):
**I admit it, this whole post was just an excuse for me to use the word “pseudocopulate.”