Natural Selection Lab
You and your fellow predators are going to simulate the process of natural selection to
see how it changes a population of insects. You are a flock of birds flying high above a
field in which a population of insects of many different colors live. We will simulate you
spotting them from above and swooping down to snatch them up. Those insects
surviving this predation will then produce new offspring, thus increasing their numbers.
We will track the change in population number for each different color variety for three
simulated cycles of predation/reproduction. Here is the procedure to follow:
A posterboard will serve as the background environment; its color should be close to
that of one of the simulated insects (fruit wheels).
Count out ten fruit wheels of each color and scatter them randomly over the entire
piece of posterboard. This will represent the initial population. Follow this direction
precisely.
All the predators should surround the posterboard, close their eyes, and on a signal by
one of you, open their eyes and snatch up the first insect they spot. You must look at
the board to simulate the predatory birds spotting their prey from above, but do it very
quickly so that you choose the one you spot first. You are trying to simulate actual
predation as closely as you can, so don’t always pick purple because that is your
favorite - pick the first one you see.
Repeat this process - close eyes, open and pick - as a group a total of five times; this
counts for ONE predation cycle. You DON’T need to keep track of any numbers yet!
To simulate reproduction of the survivors, add one fruit wheel of each color for each one
left on the board. For example, if there are four red ones left on the board after the
predation, add four more red ones.
After simulating reproduction, record the number of each color insect on the board (now
is when you need to write numbers down!)
Repeat the predation (5reps)/reproduction cycle two more times for a total of 3 cycles,
recording the number of each color present after reproduction each time.
Make sure each group member copies down all the numbers.
Clean up. You may consume the insects if you wish!