Download Name: :__ Overview: In this activity you will experience one

Name:__________________________________Period:__
Overview: In this activity you will experience one mechanism for evolution through a simulation of a predator/prey
relationship. Natural selection can be described as the process by which those organisms best adapted to the
environment are more likely to survive and reproduce than those that are poorly adapted. Organisms have
developed many different kinds of adaptations that have helped them survive in their environments. One of these
adaptations is camouflage, which is a way to escape predation from other organisms.
Objectives:
 Use an artificial environment to demonstrate the concept of natural selection
 Construct graphs to show the results of the investigation
 Predict what will happen if natural selection acts on organisms exhibiting camouflage over a period of four
generations
 Compare this artificial example to natural selection
Materials:One piece of colored background (environment)
Beginning population of paper dots (butterflies)
You (bird, predator)
Clock
Procedure:
1. Elect one “game warden” for your group.
2. The rest of the members will be predators (birds)
3. Obtain a starting population of 15 dots for each of the 6 colors for a total population size of 90. Each dot
represents an individual butterfly of the same species. The different colors represent variation within this
species.
4. The predators should turn away from the habitats (colored background). The game warden will hide the
beginning population across the background. Make sure the dots do not stick together and are evenly
spread across the environment.
5. On the game wardens’ command the predators should turn around and pick up the first dot they see. The
hunting of dots will continue for 15 seconds.
6. After the hunting has stopped, you should collect all the dots that remain on the background and sort them
by color. Record this data. Round the percent composition to the nearest tenth.
7. To simulate reproduction among the butterflies (dots), add 1 paper dot for each remaining dot of that color.
These paper dots, obtained from the bags containing extra dots, represent offspring.
8. The game warden of your group must maintain the population of butterflies between 60 and 120. The
game warden will adjust the predation time up or down from the original 15 seconds for the remainder of
the trials to do this. It’s okay to be below 60 or above 120 for one trial, but you must adjust predation time to
be back between 60-120 on the next trial.
9. Repeat steps 4-8 for a total of 4 trials.
10. Record your groups’ final percent composition on the spreadsheet. Round to the nearest tenth.
Prediction/ Hypothesis:
Before you begin the lab, predict which colors of butterflies will survive the best and which colors will be least able
to survive. Rank the six colors from the highest to lowest survival rate for both the blue and green background and
explain why you ranked them this way (1=most likely to survive, 6=least likely to survive)
Colors of
Butterflies
White
Yellow
Green
Blue
Brown
Black
Rank for Blue
Background
Rank for Green
Background
Explanation for Blue Background:
Explanation for Green Background:
Data Collection Table:
White
# at Start
Yellow
Green
Blue
Brown
Black
Total
% composition
# after 1st
predation
# after 1st
reproduction
% composition
# after 2nd
predation
# after 2nd
reproduction
% composition
# after 3rd
predation
# after 3rd
reproduction
% composition
# after 4th
predation
# after 4th
reproduction
% composition
Analysis:
11. Using Excel, create a table that lists all of the groups’ final % composition for all 6 colors of butterflies. Then
create three pie graphs comparing your groups’ final % composition to the average final % composition for
your color of background and for the other colored background. You must include both a legend and a
caption, and your % compositions must be printed onto the actual graphs.
Your legend should include: WHAT happened (which butterflies survived the best and which did
not), HOW this data compares with your predictions, and WHY you think you got these results.