We have an experiment in evolution in our own back yard – a vivid and undeniable example of natural selection at work.
Dandelions. The plague of the suburban lawn. Dandelions sound like a cute little plant, and they’re really not all that bad looking taken as just the flower. Indeed, their method of distributing seeds gets my vote as pretty darn ingenious.
Dandelions get their name from the petals of their flowers. The outer ridges look like “lion’s teeth”, at least according to some French person, which is where the “Dent de Lion” originates its name. The danger to destroying your lawn is certainly as deadly as the lion’s tooth, and their ability to evolve certainly demonstrates that.
The scourge of yellow flowers has been plaguing my lawn for too long this spring, as it is left untreated due to the unfortunate telephone tag game. “We’ll contact you in 7-10 days abut setting up an appointment.” Uh, right. Next year, we’ll be using someone else. I digress.
In any case, we’re in a bit of a pickle, since we live at the bottom of a hill from all of our neighbors, and the natural water flow through the neighborhood is pretty much through our lawn. (Yes, this stinks.) With the wave of rain runoff comes the loose dandelion seeds, which all get stuck in our high grass (uncut due to another byproduct of the aforementioned phone tag - not being around to do it). The end result is that you can see where the rain runs through our yard quite clearly by the density of yellow amongst the green.
Here’s where the evolution kicks in.
Today, the mowers finally arrived. My impression is that dandelions usually don’t survive long in a lawn that is well-groomed, and I was happy to see the mowers offload from their trailers and rev themselves over my lawn. But what happened is as shocking a demonstration of Darwin’s principles as one is likely to ever witness in person.
The mower glided over the lawn, chopping back the tall grass, but at least half of the dandelions remained. What the heck?
Here’s the thing: Every year, we cut down the dandelions that grow in our lawn, making it impossible for them to go to seed. The few dandelion flowers that do make it to seed are the ones that are too low to the ground to be cut by the mower when they are flowering. As a result, the breeding pool of dandelions consists mostly of plants that grow very short stalks, therefore surviving the slice of the mower blade.
This is why my lawn is almost entirely yellow. Dandelions have evolved via natural selection to evade the lawnmower blade and thrive as plants that lie so low to the ground that I would have to uproot my grass to get at them.
The only recourse I have is chemicals. Who knows how long I will have until evolution of the dandelion makes that option unavailable as well?!
