Rise and Fall of Phenotype Frequency
Melanism has appeared in the European and North American peppered moth populations. Information about the rise in frequency is scarce. Much more is known about the subsequent fall in phenotype frequency, as it has been measured by lepidopterists using moth traps.
Though a black peppered moth was found in 1811, this can be seen as an aberrant morph caused by a recurrent mutation that was probably selected out of the population. The first carbonaria to be found was caught in Manchester, England in 1848, but was only reported 16 years later in 1864 by Edleston. Edleston notes that by 1864 it was the more common morph in his garden in Manchester. Steward compiled data for the first recordings of the peppered moth by locality, and deduced that the carbonaria morph was the result of a single mutation that subsequently spread. By 1895, it had reached a reported frequency of 98% in Manchester.
From around 1962 to the present, the phenotype frequency of carbonaria has steadily fallen. Its decline has been measured more accurately than its rise, because of more rigorous scientific studies being conducted. Notably, Bernard Kettlewell conducted a national survey in 1956, Bruce Grant conducted a similar one in early 1996., and L.M. Cook in 2003.
Similar results were found in America. Melanic forms have not been found in Japan. It is believed that this is because peppered moths in Japan do not inhabit industrialised regions.
Read more about this topic: Peppered Moth Evolution
Famous quotes containing the words rise and, rise, fall and/or frequency:
“Only the person who has experienced light and darkness, war and peace, rise and fall, only that person has truly experienced life.”
—Stefan Zweig (18811942)
“To business that we love we rise betime,
And go to’t with delight.”
—William Shakespeare (1564–1616)
“Have you seen but a bright lily grow
Before rude hands have touch’d it?
Have you mark’d but the fall of the snow
Before the soil hath smutch’d it?
Have you felt the wool of the beaver,
Or swan’s down ever?
Or have smelt of the bud of the brier,
Or the nard in the fire?
Or have tasted the bag of the bee?
O so white, O so soft, O so sweet is she!”
—Ben Jonson (1572–1637)
“The frequency of personal questions grows in direct proportion to your increasing girth. . . . No one would ask a man such a personally invasive question as “Is your wife having natural childbirth or is she planning to be knocked out?” But someone might ask that of you. No matter how much you wish for privacy, your pregnancy is a public event to which everyone feels invited.”
—Jean Marzollo (20th century)