AP BIOLOGY

Detailed explanation-1: -The light moths blended in with the light-colored trees. However, the Industrial Revolution changed the tree colors. After the pollution from the Industrial Revolution started affecting trees, most of the collected peppered moths were of the dark form.

Detailed explanation-2: -What was rare in 1848 became common over the next fifty years. By 1900, the peppered moth populations in areas around English cities were as much as 98% dark moths. Scientists became curious why this was happening.

Detailed explanation-3: -They were losing their selective advantage to the dark moths, which, against the trees’ dark bark background, were less visible to birds. In 1848, the dark moths comprised 1% of the population and by 1959 they represented  90% of the population. So, in 100 years the frequency of dark moths increased by 1000 fold!

Detailed explanation-4: -Q. Why did the population of peppered moths in England change from the light variation to the dark variation after the Industrial Revolution? The soot from industrial revolution caused the light peppered moth to fly away, and only the dark variation was left.