Download Natural Selection Simulation

Natural Selection Simulation Lab
One useful definition of evolution is it’s a change in the frequency of a gene in a population
over time. This simulation allows the user to alter various biological and non-living
environmental factors to see how they affect a population of rabbits over several generations.
It is possible to view the natural selection of beneficial traits, and how they quickly alter the
composition of the population.
Some Background Information
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Selection Factors – these are forces that limit the number of rabbits in the population.
Environment – the location and type of habitat the population inhabits.
Chart – the manner in which population data is displayed.
Mutation – an alteration in the rabbit’s genes that lead to a different trait.
Dominant gene gives rise to a dominant trait (only one parent must have the dominant
trait in order for it to be passed to the next generation).
Recessive gene gives rise to a recessive trait (both parents must have the recessive trait
and pass it to the next generation for it to show up).
Simulation Run 1
Chose the following settings:
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Selection Factor – none.
Environment – Equator.
Chart – population.
Add a Friend and click on brown fur mutation then let run for 5 generations before
hitting pause.
How big is the population of white rabbits? _______ Brown rabbits? _________
Point to remember: All populations have a natural variability in traits (e.g., some will be white
and some will be brown).
Simulation Run 2
Chose the following settings:
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Run the same settings as Run 1 except make the brown fur recessive and the white fur
dominant.
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Allow 5 generations to pass before pausing the simulation.
What color is most abundant in the population? _____________
Why is the brown rabbit difficult to produce under these conditions?
Simulation Run 3 – How Does a Population Become Adapted to its Environment?
Chose the following settings:
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Environment – Equator.
Chart – population.
Add a Friend and brown fur mutation. When the first generation has been born add
Selection Factor “Wolves”.
Run this simulation until 5 generations have been born and then pause it (don’t reset
because it will be used later).
What color fur is most common at this time? ______________________
Selection Factors work to reduce the _______ rabbits because they are easiest to __________.
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Assume an environmental change occurred rapidly to an existing population of brown
rabbits. Restart the last simulation and click on Arctic button to change the background
of the brown rabbits. Let the simulation for 5 more generations and pause it.
How does the population respond to this environmental change?
Apply the Knowledge
Approximately 1000 years ago, sands of the desert southwest of the US were disturbed by a
volcanic eruption. Molten lava was spewed out and covered hundreds of square kilometers of
desert. Over time this lava hardened into a black rock which was in stark contrast to the light
tan color of the desert sands. The tan furred desert pocket mice that ventured onto this black
rock looking for food soon encountered visual predators of all types.
Many centuries later, Dr. Howell began a research project to document the abundance of the
tan and dark color types of desert pocket mice in the area. What do you think his report would
reveal about the relative abundance of these mouse populations?
Conclusion
This simulation showed the change in the fur color of a population of rabbits over a few
generations, but not other traits. Many traits of an organism are stressed by the environment
which will allow the population as a whole to show new traits through time. If these traits
accumulate to the point a population isn’t capable of breeding with similar type neighboring
organisms, a new species has been developed. The process of natural selection modeled here
is a major driving force of evolution and can explain the diversity of life on this planet.