peppered moth.avi. peppered moth moth comes in two “versions”:
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Peppered mothMoth comes in two “versions”:
Pre-Industrial RevolutionThe white peppered moth very commonBlended in well
Lichens, tree branches, rocks
PredatorsBirds ate the mothAny moth that did not blend in very well was
prone to get eaten
Industrial RevolutionGreat deal of smoke and soot released into
No more camouflage Soot settled on rocks,
treesBecame darkerKilled lichens
Peppered moth lacking hiding places
MelanismThe black version of the peppered moth
(previously very, very rare) now had significant advantage
Natural Selection in action!
No humans are selecting for black moths or white moths.
NatureNature is selecting against one or the other!
ResultsThe white-and-black moth went from the majority to the minorityEstimated 99.9% to 2%Black moth went from 0.1% to 98%
All of this in about a 40 year spanVERY fast on a biological timescale!
RecentlyThe US and Europe now have cleaner air
standardsWhat happened to the proportion of
peppered vs. black moths?Now shifted towards light-colored
peppered moths again