1. Module 8

1.15. Page 4

Lesson 3

Module 8—Populations, Individuals, and Gene Pools

 

Reflect and Connect

 

The photo shows a baby receiving oxygen with assistance from doctor.

© Lisa Eastman/6050238/Fotolia


 

It is possible to determine the characteristics of the Canadian cystic fibrosis gene pool. The incidence of CF in Canada is 1/2500 people, so

  • f(aa)  = q2 = 0.0004

  • the frequency of the recessive CF allele f(a) = q = 0.02

  • the frequency of the dominant normal allele (1 − q) =  p = 0.98

  • the frequency of the homozygous dominant genotype p2 = 0.96

  • the frequency of heterozygotes (carriers) f(Aa) = 2pq = 0.039

The data tells us that 98% of the alleles in the Canadian gene pool are normal and 2% are CF alleles. About 4% of the population are carriers of the CF gene. Data is not available to determine how frequencies have changed since medical technologies made it possible for CF patients to live long enough to reproduce, but we can certainly guess that the frequency of the CF allele has risen and microevolution is occurring. Of the five possible reasons for this evolution, natural selection is the closest explanation. But is it nature that’s selecting or the environment created by humans and our technology? This is called artificial selection. Although artificial selection is grouped with natural selection as a cause of evolution, there is debate as to whether or not it is a cause of evolution.


Before submitting your Module 8: Lesson 3 Assignment, you may wish to review pages 678 to 688 of your textbook, which is the section on the Hardy-Weinberg principle. Your teacher may suggest questions, other than questions 1, 2, 3, and 8, from page 688 that you could use as review. Consult with your teacher for answers to the questions that you decide to complete.

 

Module 8: Lesson 3 Assignment

 

Go to the Module 8: Lesson 3 Assignment that you saved to your computer at the start of this lesson. Complete Part 1.

 

When you've finished Part 1, complete Lesson 3: Lab. All of your answers to the lab go in Part 2 of the Lesson 3 Assignment.

 

Submit your completed Module 8: Lesson 3 Assignment to your teacher for assessment