31 October 2012

The creature from the black puddle

The Creature from the Black Lagoon
The eggs, nestled in a protective jelly stained golden by tannins that glistened in the light, might have looked like any other clutch of salamander eggs from a woodland pond. But they weren’t, and this was no pristine sylvan pool. It was a roadside puddle, and those eggs promised to contain something unsettling. If Brady was right, the toxic brew associated with road run-off had forced the spotted salamanders to evolve in the space of decades. In the time since Neil Armstrong first set foot on the moon in 1969, these animals had been reinvented by nature to cope with life on the road.
--from Unnatural Selection by Emily Monosson, published by Aeon magazine.

Persistent sub-lethal exposure to toxic chemicals is enough to drive evolution in salamanders and other creatures. From this, other thoughts follow:
Is it possible that the genomes of vertebrate populations are not as recalcitrant to change as we once thought? What if they harbour subtle genetic variants, like ghosts from environmental challenges past, offering a degree of flexibility in the face of change? Perhaps...[the] salamanders are harbingers of discoveries to come. It might even be that rapid evolution in response to toxic chemicals is quite common. A further...question suggests itself. If life can adapt, why bother with expensive environmental cleanup? Why not let nature take its course?
The answer is "both intriguing and deeply troubling":
Industrial chemicals might have effects that are widespread and heritable, yet also maladaptive, not only in humans but in all life on earth...
We certainly have not escaped the chemical gauntlet. We might yet experience a far more insidious kind of rapid evolution through chemically induced epigenetic alterations. How these will influence the evolution of human populations is anybody’s guess. Perhaps they will be of little consequence...[or] perhaps humans in the not-so-distant future will become unwitting actors in a real-life science fiction, fending off hoards of fecund, rapidly evolving chemical-resistant pathogens and insects even as we are weakened through the accumulation of myriad changes of our own making.

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