One of the easiest to understand examples of natural selection is the Peppered moth, which is why it’s so commonly found in textbooks on the subject. As Wikipedia puts it:
The evolution of the peppered moth over the last two hundred years has been studied in detail. At the start of this period, the vast majority of peppered moths had light coloured wing patterns which effectively camouflaged them against the light-coloured trees and lichens upon which they rested. However, due to widespread pollution during the Industrial Revolution in England, many of the lichens died out, and the trees which peppered moths rested on became blackened by soot, causing most of the light-coloured moths, or typica, to die off due to predation. At the same time, the dark-coloured, or melanic, moths, carbonaria, flourished because they could hide on the darkened trees. Since then, with improved environmental standards, light-coloured peppered moths have again become common, and the dramatic change in the peppered moth’s population has remained a subject of much interest and study.
We wrote about the return of the light-colored version — see The Peppered Moth is Turning White Again.
The peppered moth — for obvious reasons — is despised by creationists. For example, ol’ Hambo claims it’s really evidence of creationism — see Ken Ham and the Peppered Moth.
Today there’s lots of headlines about a new study of the little critters. This is in PhysOrg: Study confirms truth behind ‘Darwin’s moth’. Here are some excerpts, with bold font added by us for emphasis, and occasional Curmudgeonly interjections that look [like this]:
Scientists have revisited — and confirmed — one of the most famous textbook examples of evolution in action. They showed that differences in the survival of pale and dark forms of the peppered moth (Biston betularia) are explained by how well camouflaged the moths are to birds in clean and polluted woodland.
This is what they’re talking about: Avian vision models and field experiments determine the survival value of peppered moth camouflage. It’s in Communications Biology, and you can read it on-line without a subscription. Okay, back to PhysOrg. They say:
[N]obody had ever tested how well camouflaged the moths were to the vision of their key predators — birds — and how their camouflage directly influenced survival. Now scientists at the University of Exeter have shown that, to the vision of birds, pale moths are indeed more camouflaged against lichen-covered trees than dark moths — making pale moths less likely to be eaten by birds in unpolluted woodland and giving them an evolutionary advantage.
They quote one of the lead authors of the study:
“This is one of the most iconic examples of evolution, used in biology textbooks around the world, yet fiercely attacked by creationists seeking to discredit evolution,” said Professor Martin Stevens, of the Centre for Ecology and Conservation on the University of Exeter’s Penryn Campus in Cornwall.
“Remarkably, no previous study has quantified the camouflage of peppered moths, or related this to survival against predators in controlled experiments. Using digital image analysis to simulate bird vision and field experiments in British woodland, we compared how easily birds can see pale and darker moths, and ultimately determine their predation risk. Our findings confirm the conventional story put forward by early evolutionary biologists — that changes in the frequency of dark and pale peppered moths were driven by changes in pollution and camouflage.“
There’s a lot more in the PhysOrg article, but that’s enough to give you the general idea. Now we’ll watch for the inevitable creationist reactions. They won’t be able to ignore this one!
Copyright © 2018. The Sensuous Curmudgeon. All rights reserved.