Biology 11
Studies
1.
Natural Selection – Case
Darwin’s Finches
Darwin’s observation:
Darwin discovered _______________ different species of finches on the Galapagos Islands, but
found only ____________ species of finch on the mainland of South America.
Darwin’s explanation:
● the Galapagos Islands are _____________________________ than the continent
of South America. (The Galapagos are volcanic islands. They lie 1000 km west of
mainland South America.)
● after the Galapagos Islands were formed and colonized by plants, an ancestral
flock of finches arrived at the islands. How could this happen?
______________________________________________________________
______________________________________________________________
● Once the ancestral flock arrived at the islands, there was very little
_________________________________ because _________________________
__________________________________________________________________
The finches had an unlimited food supply consisting of _________________,
____________________________ and _____________________________.
● The flock of ancestral finches would contain birds with a variety of beaks. Each
type of beak was adapted to a different food source. For example, birds with big
beaks could ______________________________ more easily than birds with
slender beaks, but birds with slender beaks could ________________________
________________________________________________________ more easily
than birds with thick, heavy beaks.
● Some of the finches migrated to other nearby islands in the Galapagos group.
The islands are ecologically different. A different type of beak would be favored
in each separate ________________________________________.
● As a result of each bird population being _____________________________ (on
different islands and/or in different habitats), separate ____________________
of finches evolved.
● There is only one species of finch on the South American mainland because
__________________________________________________________________
__________________________________________________________________
Darwin’s finches provide an example of ________________________________
_________________________________ - the evolution of several new species from a
common ancestor into new ecological or geographical areas.
2. The peppered moth
● Peppered moths can be __________________ or _______________________
colored. The dark (or melanic) form is caused by a ________________________.
In a population of peppered moths, there are always some black and some white
moths.
● In the early 1800’s, the white form of the peppered moth was the most
common. The white form blended in with the ________________________ on
trees. This protected the moth from __________________________________.
● During the Industrial Revolution in the mid-1800’s, ________________ from
factories killed the lichen and __________________________________ the tree
trunks. Now the black form the moth was _______________________________
for birds to see because the black form matched the tree trunks.
● Through natural selection, the population of the peppered moth shifted from the
________________________form to the _________________________ form.
● The selecting agents were the _______________________________________
and the _________________________________________
Consider the following experimental data:
Location 1
Unpolluted area
473 black moths are released
30 black moths are recaptured
% recaptured = ____________
496 white moths are released
62 white moths are recaptured
% recaptured = _____________
Location 2
Polluted area
447 black moths are released
130 black moths are recaptured
% recaptured = ____________
137white moths are released
18 white moths are recaptured
% recaptured = _____________
Explanation:
Explanation: