Name: _____________________________________________
Period: ___________
Natural Selection Simulation
Go to the Natural Selection simulation. https://phet.colorado.edu/en/simulation/natural-selection
● Click “play”
● Click “lab”
This is what you should see:
Timer (Ignore this)
Environment controls
Time control
Population graph
Part 1: Teeth
Traits and environmental factors
Reset everything using the
button. Click on the
on the left under the dominant
column to add a mutation. Click “Add a Mate”. After 3 generations have passed on the graph
click
to pause the simulation.
1. Based on the population numbers, which type of tooth is the predominant trait so far?
Short teeth
2. Do the current environmental conditions favor one type of tooth? Use evidence to
support your answer. (Hint: the “proportions” setting next to the graph can provide
evidence as well)
It favors short teeth, since there is a greater proportion of them.
3. PREDICT: What would happen to both the populations of long teeth and short teeth
rabbits if the food became tough? What would happen to the proportion of long teeth to
short teeth?
The population and proportion of rabbits with long teeth would increase and the population and
proportion of short teeth would decrease
DO NOT RESET. Click the “tough food box”, then click
to restart the simulation. After 7
generations have passed, pause the simulation to check your predictions.
4. Were your predictions correct? Use evidence to support your claims.
Yes, now the proportion of long and short teeth rabbits are 50%.
5. Write the REASONING for the following claim: Long teeth in rabbits is a favorable
mutation when food sources are tough.
Since rabbits with long teeth can bite through the tough food easier than rabbits with short teeth,
more are going to survive.
Part 2: Fur
Reset everything using the
button. Click on the
on the RIGHT under the recessive
column to add a mutation. Click “Add a Mate”. After 3 generations have passed on the graph
click
generations.
while letting the simulation run. Pause
the simulation after 8
6. How did the proportion of white bunnies to brown bunnies change after wolves were
introduced to the environment? What would be a reasonable explanation for this
change?
The proportion of white bunnies to brown bunnies decreased, since most white bunnies are
killed by the wolves since they are easier to spot.
7. Based on the evidence, what is the difference between a dominant trait (white fur) and a
predominant trait?
Dominant traits are the traits that a specie starts with. predominant trait is the result of the changes in environment.
DO NOT RESET. Click the
then click
have passed, pause the simulation.
to restart the simulation. After 12 generations
8. What effect did the change in environmental conditions have on the rabbit population?
More white rabbits survived, their population and proportion increased.
Conclusion
9. Go back to the lecture video and look for the or the prezi and search for the How it works
section. Mr. Morris has 5 Steps written on the prezi. Explain in as much detail as you can
each of the 5 steps by using the bunnies in this lab as an example.
1. Overproduction:
As generations pass on, the population of rabbits increases exponentially, eventually
taking over the world.
2. Variation: (Make sure to talk about the original source of variation. How did the new
alleles appear?)
Originally, all rabbits were white. However after mutations and natural selection, variations were
created in the population.
3. Competition:
Species have to compete with each other to survive. For example, when food became tough,
the rabbits with long teeth could eat the food while rabbits with short teeth can’t, eventually
leading to a decrease in short teeth population and proportions.
4. Successful competitors survive, reproduce, & pass on their traits
When wolves were introduced, many white rabbits were killed off since they are easier to spot
by predators. As a result, the population of brown rabbits increased drastically.
5. Repeat steps 1-4 for millions of years. (This is not shown in the lab but you can
speculate as to what would happen if this process would continue. REMEMBER NEW
MUTATIONS AND THUS NEW ALLELES WILL CONTINUE TO APPEAR!)
More variations will be created in the species as new mutations occur.