Name ________________________________________________________ Block __________

 

Genetic Drift: One Way Allelic Frequencies Can Change

 

Go To the website: http://evolution.berkeley.edu/evolibrary/article/evo_24

 

1.      What is genetic drift?

 

 

2.      Unlike natural selection, genetic drift is ______________________________________.

 

In the search bar in the upper right-hand corner type “Sampling Error and Evolution” and then select it from the list.

3.      What does genetic drift reduce in a population?

 

 

4.      Does genetic drift have more of an effect on a large population or a small population?

 

 

5.      What can genetic drift contribute to?

 

 

In the search bar in the upper right-hand corner type “Effects of Genetic Drift” and then select it from the list.

6.      What happens if the allele causing the green marble drifts out of the population?

 

7.      What two processes could reintroduce the green allele into the population?

 

 

8.      What is the problem with having less genetic variation?

 

 

Click on the next page at the bottom of the page.

9.      Why is genetic drift more of a problem in small populations?

 

 

In the search bar in the upper right-hand corner type “Bottlenecks and Founder Effects” and then select it from the list.

10.  What is a population bottleneck?

 

 

11.  What is the founder effect?

 

 

12.  The small population size caused by the founder effect causes what two traits in the colony?

 

Go to the website: http://glencoe.mcgraw-hill.com/sites/9834092339/student_view0/chapter20/simulation_of_genetic_drift.html

 

1.      Why is genetic drift a more powerful force in small populations?

 

 

Click on the play button:

2.      What is random genetic drift?

 

 

3.      What is the fixation of an allele?

 

 

4.      If a population size is small (about 20 individuals), what happens to the A allele (follow the red line)?

 

 

5.      If the A allele is lost, what happens to the a allele?

 

 

6.      In the second simulation of a small population, what happens to the A allele (follow the purple line)?

 

 

7.      If a population size is large (about 1000 individuals), what happens to the A allele (follow the black line)?

 

 

Answer the questions below the simulation and then submit your answers. Write the correct answers below. Do NOT e-mail your results.

 

8.      Genetic drift ____________________________________________________________.

 

 

9.      The effect of genetic drift is much more significant in __________________ populations.

 

 

10.  If the frequency of an allele reaches 1.0, the allele is said to be _____________________.

 

 

11.  Genetic drift refers to the movement of individuals between populations.  True or False?

 

 

12.  Genetic drift is a random process. True or False?