Natural Selection Simulation

Transcription

1 Group Members: Date: Natural Selection Simulation Get a laptop computer and open the internet and go to: 1. Click the Run now button. When the simulation begins, you will notice a single bunny in the environment. There is also a graph along the bottom that shows the population change over time. As the bunny continues to jump around, what do you notice is happening on the graph at the bottom? 2. If you allow some more time to continue, the bunny will die from being forever alone. Click the play again to get a new bunny. This bunny looks lonesome. Click the add a friend button and describe what happens. The graph can be zoomed out using the magnifying glass at the top left corner of the graph. Zoom the graph out. Allow several generations to pass. Draw what the graph looks like: 3. Why do you think that the bunnies have taken over the world? 4. Notice on the top right of the controls there are several selection factors. These are factors that can control the bunny population. Click the play again button. Add a friend for the lonesome bunny and add some wolves to control the bunny population. What happened? 5. Click the play again button. Add a friend for the lonesome bunny and wait a bit to allow the bunnies to make more bunnies before adding the wolves (wait till there are more than 50 bunnies). Describe what happened.

2 6. This is common in nature. Whenever a single species begins to become overpopulated, it becomes an easy food source for another species. As there are more bunnies, there are more wolves. More wolves need more bunnies to feed on, and the population is controlled. Our simulation is not taking into account that the bunnies need to eat. Click the play again button. Add a friend for the lonesome bunny and then add Food as a selection factor. Describe what happens. (If your bunnies survive for a long time, wait a few minutes then describe what happened) 1 7. Draw a picture of what the graph looks like: 8. How would you explain this graph? Why does it look like it does? 9. Mutations happen in nature. The word often has a negative sound because often mutations are bad. However, sometimes mutations result in a good trait. Notice the Add a Mutation section on the top right of the controls. Click the Reset All button on the bottom left of the controls. Add a friend for the forever alone bunny. This time add a Long Teeth mutation. Now add Food as a selection factor. The pink line on the graph represents the amount of long teeth bunnies in the population. The tan line represents the number of short teeth bunnies in the population. Describe what happens to the overall makeup of the bunny population. (Think how many have short verse long teeth) 10. Why do you think this happened? (Think about food as a selection factor and long teeth as a new trait) 11. The long teeth probably help the bunnies get food more easily then the short teeth. In this case the long teeth are a good mutation. Notice that Brown Fur is also a possible mutation. What do you predict will happen if we add bunnies with brown fur and wolves in the same simulation?

3 12. Test your prediction. Reset the simulation and give the bunny a friend. This time add the Brown Fur mutation to the population. Add the wolves in a bit and describe what happens. 13. Why do you think that the brown bunnies became so numerous? 14. Do you think brown fur will help bunnies if the selection factor is food? Why? 15. Test it out. Reset all and give the bunny a friend. Now add brown fur as a mutation. Why do you think the brown mutation does not overtake the population when Food was a selection factor like it did with the wolves? 16. How do you think both the Brown fur and Long teeth mutations will affect the whole populations of bunnies when both wolves and food are selection factors? Predict what the population will look like. 17. Reset the simulation and add a friend. Add the brown fur mutation and then add the long teeth mutation. Add the food selection factor. Wait a generation to pass, then add the wolves as a selection factor. You can alternate back and forth a few times. Was your prediction correct? 18. Brown fur is a good trait to help hide from wolves when the ground is brown. The wolves will find the white bunnies easier than the brown bunnies, eat them, and reduce the amount of white bunnies that can reproduce for the next generation. Brown fur bunnies are left and reproduce. Reset your simulation. Add a friend for the bunny and add brown fur as a mutation. Now wait till there are more than 50 bunnies (check the graph) and add wolves. After a few generations you will notice the brown bunnies are the majority of the bunny population. Switch the environment to Artic. Describe what happens to the fur color of the bunny population after a few generations.

4 19. Why did this happen? 20. What would happen if the snow melted and the ground was brown again? 21. Why do you think polar bears, artic hares, and artic foxes have white fur? 22. Fur color can either be a good or bad adaptation depending on the environment the bunny lives in. Some mutations result in traits that are always bad for a species. If the bunny were to mutate longer tail, this would make it easier for a wolf to catch them. What do you predict would happen to the mutation of long tails in bunnies if wolves are a selection factor? 23. Reset your simulation. Add a friend for the lonesome bunny and add a long tail mutation. Wait till there are more than 50 bunnies (check the graph) and add wolves. Was your prediction accurate? 24. Explain why the long tail trait disappeared from the bunny population. 25. Lastly, we will combine long tails and brown fur to our bunnies. This will make four different kinds of bunnies: white bunnies with short tails, white bunnies with long tails, brown bunnies with short tails, and brown bunnies with long tails. What do you think will happen if we add wolves? 26. Which bunny type do you think would be the least common in the environment? 27. Which bunny type would do you think would be the most common?

5 28. Reset your simulation and add a friend. Add the mutation for brown fur and then add the mutation for long tails. Wait till you have over 50 bunnies and add wolves as a selection factor. Were your predictions correct? 29. When the bunnies have taken over the world, DO NOT press the play again button. (If you did, you need to redo the simulation from the previous question) Instead of play again, close the window of the picture of the bunny world by pressing X at the top right of the window. Draw the graph after the last simulation. Add a line for each trait (brown fur, white fur, short tail, and long tail). Make sure you use different colors for each line and label them.