Download Name

Name:_______________________________
Period:__________
Online Activity 10.5
www.pearsonsuccessnet.com
Login: Student
Password: test07
Page 1 Objective: to determine how the white-eyed trait in fruit-flies is inherited.
1. How can you distinguish between male and female fruit flies? What is the normal phenotype for
the fruit flies?
2. What was Thomas Morgan’s new discovery? Click the jar to find out and write your answer
below.
3. When the red-eyed female mates with a white eyed male, what is the observed F1 offspring
phenotype?
4. When two members of the F1 generation are crossed white eyed flies are observed. Fill in the
chart below with the appropriate numbers:
Red-eyed females
White-eyed males
Red-eyed males
White-eyed males
5. Write the genotypes for the parental generation and show the punnet square cross. Indicate in each
square the eye color, genotype and sex of each fly.
6. Write the genotypes for the F1 generation and show the punnet square cross. Indicate in each
square the eye color, genotype and sex of each fly.
7. Explain why the male fruit fly, but not the female, demonstrated the white-eyed trait after the cross
between the F1 generation.
8. Is it possible to have a white-eyed female? If so, what cross would you perform to produce a
white-eyed female? Show the punnet square for this cross.
9. Mutations are relatively rare events, and Morgan's white-eyed male fly probably arose because of
a mutation. Why is it more likely that you would observe a white-eyed male fly, rather than a
white-eyed female fly, as a result of a new mutation?
Review:
1. In humans normal pigmentation (P) is dominant to being albino (p). A normal pigmented man and
an albino woman have children with the normal phenotype. What is the man’s genotype?
2. The ABO blood group found in humans is an example of:
a. incomplete dominance
b. multiple alleles
c. polygenetic
3. What are alternate forms of a gene which influence the same trait called?
4. Two true-breeding (purebred) plants, one for the tall phenotype (which is dominant) and one for a
short phenotype (the recessive condition) are crossed. What is the chance that their offspring will
be short plants?