Download Peppered Moths Web Activity

NATURAL SELECTION
Peppered Moths Simulation
Peppered moths are a classic example of natural selection – and one of the first times scientists
were able to observe and document the principle of Natural Selection in action. This web
activity will help us see how natural selection works as different versions of a trait result in
increased survival and reproduction of moths in different environments.
Directions:
1. Go to http://peppermoths.weebly.com/
2. Click on ‘Life Cycle of a Peppered Moth’
3. Use arrow key to continue thru pages, answering questions below as you go.
a. What are the predators of peppered moths?
b. Why do moths sit on trees during the day?
c. What does the moth wing pattern resemble?
d. How do moth larvae (caterpillars) avoid predation?
e. While most moths were light colored, describe the other color variations.
4. Click on “Pollution and Peppered Moths”
a. While very rare in the early 1800’s, by the 1900, most moths were _________
b. What impact did the Industrial Revolution have on the trees surrounding the
cities?
c. What were 2 initial hypotheses about why the moths were now mostly dark?
d. What was actually the cause of the dark moth’s appearance?
5. Click on ‘Dr. Kettlewell’s tests natural selection’
a. What does an entomologist study?
b. In Kettlewell’s experiment, he captured, tagged, released, then recaptured moths.
Which moths were most likely to survive in:
a light forest –
a dark forest –
6. Click on ‘Bird’s Eye View’ and complete 2 trials in dark forest and 2 trials in a light forest.
Complete chart below.
% light
moths starting
% dark
% light
moths moths –
starting
ending
Light Forest
Trial 1
Trial 2
Average
Dark Forest
Trial 1
Trial 2
Average
7. Analysis: Do your results match Kettlewell’s results? EXPLAIN.
% dark
mothsending
Darwin’s Theory of Natural Selection
Skim section 15-1 then answer the following questions:
1.
Who was Charles Darwin?
2.
Where are the Galapagos Islands?
3.
What did he notice about the organisms on the Galapagos Islands?
5 MAJOR PRINCIPLES (STEPS) OF NATURAL SELECTION
1. There is variation (differences) among offspring, caused mainly by genetic
differences.
2. In nature there is an overproduction of offspring. Or, many more young are
produced than are able to survive.
3. There is struggle for existence as organisms must compete for limited
resources (such as food, space, etc).
4. There is differential survival and reproduction among organisms: individuals
born with favorable variations (traits) that are better suited to their particular
environment are more likely to survive and/or reproduce – passing on the
favorable traits to their offspring (who pass it on to their offspring, who pass
it on to their offspring, etc.) Other organisms die sooner and/or leave fewer
offspring.
5. Population shift: over time, the population will be mostly made up of
organisms with the favorable traits.
Examples: apply the 5 major principles (steps) of natural selection to the following
2 examples:
Peppered Moths Example:
1.
2.
3.
4.
5.
Hummingbirds:
Watch video clip #4 at:
http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html
1.
2.
3.
4.
5.