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The dark-colored peppered moth is on the verge of extinction. And it IS very likely because of human activity. Voila! Evidence that humans are bad for species and ecosystems!

Might I urge everyone to just take a deep breath and to think harder when information is presented to you?

It turns out that the dark colored peppered moth was likely a creation of human beings in the first place. Was its creation sustainable? Is its demise evidence of unsustainability? Well, this is why standard “definitions” of sustainability will lead us off into the vaguely phosphorescent recesses of the great grimpen mire. It turns out that the peppered moth is generally light colored. In the mid-19th century it began to turn black, and yes because of human activities coupled with the wonders of evolutionary processes. As cities in England got dirtier and dirtier, and the air and particulates coating all surfaces got darker and darker – the darker colored moths had an easier time hiding from predators, particularly when they were roosting in trees. Over time, evolutionary processes took over – being dark conferred an advantage and soon nearly all of the peppered moths in England were dark.

Not anymore. It is thought that the dark-colored strain of the moth is about to go extinct? Why?

The same human influences, this time running in reverse. We humans have managed to clean the air and particulate matter from London and many of our major cities. Things are lighter, brighter and healthier. As a result, the naturally lighter-colored moths now have an advantage in camouflage, and the darker ones now stand out in the clean skies and trees – so they are not very likely to have their genes passed onto the next generation.

Should we do the “sustainable” thing and ensure that future generations can enjoy what present generations enjoy? Should we dirty the air a bit so that this creature of dirty air can sustain itself? I don’t think many folks would suggest that. And in thinking more deeply about the meaning of sustainability, without being too moralistic here, I hope the story helps folks understand that the world and ecosystems are always changing, and adapting to hundreds and thousands of stimuli, some human created, some not – and that the very simplistic concept of sustainability is not well-suited to describing, and acting in, the very complex world we live in.


One Response to “Species Extinction and Sustainability: The Case of the Pepper Moth”

  1. jb says:

    Good post. I wonder if, when the “experts” count the number of life forms lost as a result of human activity, etc. they provide a net figure. Seems to me we have created quite a few variations of species, from this moth to chickens, cattle, cocker spaniels,….

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