Genetic Monster
Purpose: To practice Punnett squares in a fun and creative way! 
Procedure:
1. Determine your traits as the parents of your baby monster. Flip the coin two times (once for each allele) to determine your
genotype for each trait listed on the worksheet.
 Heads = Dominant Allele
 Tails = Recessive Allele
3. Construct Punnett squares to determine the possible genotypes for each trait in your baby monster.
 If the Punnett square shows a greater than 50% probability for a phenotype, that trait will be present in the baby
monster.
 If the Punnett square shows a 50% probability for each of the two possible phenotypes, flip a coin. If the coin shows
heads, your baby will show the dominant phenotype. If the coin shows tails, your baby will show the recessive
phenotype.
4. You will be determining your genotype and the genotype of your baby for the following traits:
Horns on head-
Head Shape-
Neck Length-
# of Arms
Yes
H
No
h
________
Triangle T
Oval
t
________
Long L
Short l
________
Four
Two
A
a
________
Spots-
Yes
No
S
s
________
# of Eyes-
One
Two
E
e
________
Ear Shape-
Pointed P
Flat
p
________
Claws
Sharp C
Flat c
________
Wings-
Yes
No
W
w
________
# of Legs-
Four
Two
F
f
________
Is it . . . “A One-Horned, One-Eyed Flying Purple People Eater”? WS
Trait
Horns on head
Head Shape
Neck Length
# of Arms
Spots
# of Eyes
Ear Shape
Claws
Wings
# of Legs
Parent 1
Genotype
Parent 2
Genotype
Baby’s Phenotype
Name: __________________________________________________________________________________________________
Using the phenotypes you have determined, draw a picture of your monster baby. Use the questions on the worksheet
to write a description of your monster. Be accurate and creative!
Is Baby a Boy or Girl? __________________________________
(flip a coin: Head= Boy, Tails=Girl)
Monster Punnett Squares:
You and your partner determine what your baby will look like.
Horns on Head
Dominant = Yes
Genotype: ______________
Recessive = no
Phenotype: _____________
If it is 75% Dominant, than choose the dominant trait.
If it is 50% Dominant & 50% recessive, than flip a coin to decide what trait the baby has.
Head Shape
Dominant = Triangle
Recessive = Oval
Genotype: ______________
Phenotype: _____________
Neck Length
Dominant = Fat
Recessive = Thin
Genotype: ______________
Phenotype: _____________
# of Arms
Dominant = 4
Genotype: ______________
Recessive = 2
Phenotype: _____________
Spots
Dominant = Yes
Genotype: ______________
Recessive = no
Phenotype: _____________
# of Eyes
Dominant = 1
Genotype: ______________
Recessive = 2
Phenotype: _____________
Ear Shape
Dominant = Pointed
Genotype: ______________
Recessive = Flat
Phenotype: _____________
Claws
Dominant = sharp
Genotype: ______________
Recessive = Dull
Phenotype: _____________
Wings
Dominant = Yes
Genotype: ______________
Recessive = no
Phenotype: _____________
# of Legs
Dominant = 4
Genotype: ______________
Recessive = 2
Phenotype: _____________
If it is 75% Dominant, than choose the dominant trait.
If it is 50% Dominant & 50% recessive, than flip a coin to decide what trait the baby has.
Questions:
1. What is the name of your Monster? _____________________________________________________
2. What does it eat? ___________________________________________________________________
3. What planet does it live on? ___________________________________________________________
4. What type of animal eats them (predator)? _______________________________________________
5. How many earth years does it live? _____________________________________________________
6. How much do they weigh? ___________________________________________________________
7. How do the multiply? _______________________________________________________________
8. (Draw a dihybrid Punnett square) If you crossed a monster that was Heterozygous for # eyes &
Homozygous for dull claws with a monster that was Homozygous one eyed monster who is
Heterozygous for their claws
a. Key: ________________________________________________________
b. Cross: __________________________________
c. How many will be: 2 eyed & sharp claws ______
d.
2 eyed & dull claws_____
e.
1 eye & sharp claws _____
f.
1 eye & dull claws _____