But this does not provide proof of ongoing evolution:
But farmers sprayed so much Roundup that weeds quickly evolved to survive it. “What we’re talking about here is Darwinian evolution in fast-forward,” Mike Owen, a weed scientist at Iowa State University, said.
In all likelihood what the farmers are seeing is the rapid population of a mutant breed of weeds that already existed but is now thriving in the absence of any non-roundup based weed control. It’s nice to think that this is an example of macro-evolution in action, but I suspect that this is simply the proliferation of an existing species. Maybe not, but it’s more likely.