C. Example 3 of Darwinian Evolution ANSWERS
The Peppered Moth of England
This speckled species prior to the 1840’s occurred only as L I G H T
colored moths.
These light colored moths
rested during the daytime on the light colored
L I C H E N S (an association of
a fungus plus an
algae) located on tree trunks.
The birds which preyed on these moths did not spot them
easily.
Can you easily spot them in
both the above photos?
By the 1840’s, pollution from C O A L - B U R N I N G factories had killed
many of the light-colored lichens and
had also deposited soot on the now
blacker tree trunks.
In 1848, the first D A R K colored M U T A
N T peppered moth was found.
This is the same species of moth,
just a new color variety.
Since the tree trunks were now rather
L I G H T in color, the birds of the
polluted region more easily fed
on the LIGHT colored moths in the
industrialized parts of England.
Do you see the moth?
But there are really two moths in this photo. At first
glance, you probably did
not see the moth on the left, since it was
well camouflaged and seldom eaten by
the hungry birds.
By 1895, nearly 99%
of the peppered moths in the industrial parts of England
were the DARK
(color) M U T A N T form.
Industrial areas are marked on this map with dark
circles.
Italics Bio H
For industrialized England, the G E N E F R E
Q U E N C Y of the dark
moths I N CREASED, while the
G E N E F R E Q U E N C Y of the light
moths
D E CREASED.
This
case study is known as I N D U S T R I A L M E L A N I S
M
(This is the same root word as
for Melanin!)
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