Changes

==='''Industrial melanism'''<ref>[http://www.darwinismrefuted.com/mechanisms04.html| Darwinism Refuted] accessed on 24 March 2007</ref>===

==='''Industrial melanism'''<ref>[http://www.darwinismrefuted.com/mechanisms04.html| Darwinism Refuted] accessed on 24 March 2007</ref>===

In England during the industrial revolution pollution killed mosses and lichens on tree trunks, turning them from light colors to dark brown. Before this occurred most specimens of the peppered moth Biston betularia had white wings with black spots - giving a peppered appearance. During the period with dark tree trunks (1849 to circa 1970) the white version of betularia was easily predated on by birds, decreasing the frequency of the white-wing allele. Individuals with dark wings caused by high concentrations of melanin became much more frequent and the allele frequency for melanic moths increased. When pollution levels were reduced in the late 1960s the trees gained more moss and lichens, making the trunks lighter and predation selected against melanic forms of the peppered moth. It is now thought that the proportions of white to melanic moths in England have now returned to pre-1849 levels.

In England during the industrial revolution pollution killed mosses and lichens on tree trunks, turning them from light colors to dark brown. Before this occurred most specimens of the peppered moth Biston betularia had white wings with black spots - giving a peppered appearance. During the period with dark tree trunks (1849 to circa 1970) the white version of betularia was easily predated on by birds, decreasing the frequency of the white-wing allele. Individuals with dark wings caused by high concentrations of melanin became much more frequent and the allele frequency for melanic moths increased. When pollution levels were reduced in the late 1960s the trees gained more moss and lichens, making the trunks lighter and predation selected against melanic forms of the peppered moth. It is meow thought that the proportions of white to melanic moths in England have meow returned to pre-1849 levels.

==='''Sickle cell anemia'''===

==='''Sickle cell anemia'''===