Describe the basics of Endler’s guppy study (what did he discover an
Describe the basics of Endler’s guppy study (what did he
discover and how did he test it?), AND explain how
selection in the guppy study differed from that which the
finches on Daphne Major experienced following the
American zoologist John Endler tested Darwin’s theory with
common aquarium fish guppy. He discovered guppies with
differential colouration and spottings. some guppies with
vivid colours and large spots while the others with light
drab colour and small spots at different parts of the water
stream. He observed that the colour pattern of male guppy
is related to its predator stress. Male guppies with bright
colour and large spots have a reproductive advantage in
attracting the female, besides which it also cat ch the
attention of the predator fish. So male guppies living in
streams where there were many predators tend to possess
light colouration and small spots. In absence of the
predator, guppies tend to possess bright colours.
In Endler\’s guppy study, the frequency of predator is
selecting the colour of the male fish. Here natural
selection drives in favour of the male in terms of escaping
from predator vs attracting the female. The finches in
Daphne major has no predators or competitors. The
medium ground finch evolution is only influenced by the
weather, so the availability of food.
Normally, the medium ground finch are variable in size and
shape which has the stubby beaks and eats mostly seeds.
when drought occurred, the larger beak size gain
advantage in utilising alternate food, and they survived.
Due to differential survivability, they gain the reproductive
advantage and hence evolved into new species.