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CHAPTER 3 COMPREHENSIVE LAB
HEREDITY, PUNNETT SQUARES, & PEDIGREES
From CELLS, HEREDITY, & CLASSIFICATION
NAME ___________________________
PERIOD _______
Imagine that you are a designer for a toy company that makes toy alien bugs. The
president of Bug Builders Inc., wants new versions of the wildly popular Space Bugs, but he
wants to use the bug parts that are already in the warehouse. It’s your job to come up with a
new bug design. You have studied how traits are passed from one generation to another. You
will use this knowledge to come up with new combinations of traits and assemble the bug parts
in new ways. Model A and Model B will act as the “parent” bugs. The two models currently
available are shown on page 76 of your textbook.
Materials:
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16 Allele sacks (supplied by your
teacher)
Large marshmallows (head and
body segments)
Red and green toothpicks
(antennae)
Other colors of toothpicks (to attach
body parts together and for legs)
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Green and blue thumbtacks (noses)
Pipe cleaners (tails)
Green and red gumdrops (feet)
Googly eyes
Scissors
Glue
Flowers (girl bugs only)
You will work with a partner for this project. You and your partner will be creating ONE
new bug design. The other pairs in your class will be creating designs of their own. Remember
– even though you will be working with a partner, you must each complete your own lab paper
and will be graded on the paper that you submit, not your partner’s paper. We will be working
on this lab for a few days, so make sure you do not lose your paper!
You will not get to choose which traits your bug has – we will follow Mendel’s Laws of
Heredity, which dictate that genes and traits are passed down randomly from the parents to the
offspring (aka the Law of Independent Assortment). We will also follow Mendel’s Law of
Segregation, which tells us that each parent will donate one allele, or set of instructions, for
each bug trait. This means that you will randomly choose one allele from the “mom” bug
(printed on red paper) and one allele from the “dad” bug (printed on blue paper). This process
will simulate that production of the sex cells in the parent bugs and the subsequent passing on
of those sex cells to the offspring. When you have collected all of the alleles you need for your
baby bug, you will match up each homologous pair of alleles, simulating fertilization. This
packet contains tables for you to record your data and questions that you need to answer.
Make sure you fill out all tables and answer all questions before you turn in your packet!
First…
Before you begin building your baby bug we want to know the possible genotypes of the
parent bugs. You can see the phenotypes of the parent bugs by looking at the models or by
using the information on page 76 of your textbook. You will also need the information on page
77 to fill in the table below.
Possible Genotypes of the Parents
“MOM” BUG
TRAIT
PHENOTYPE
POSSIBLE GENOTYPE(S)
Antennae Color
# of Body Segments
Tail Shape
# of Leg Pairs
Nose Color
Foot Color
# of Eyes
Gender
“DAD” BUG
TRAIT
Antennae Color
# of Body Segments
Tail Shape
# of Leg Pairs
Nose Color
Foot Color
# of Eyes
Gender
PHENOTYPE
POSSIBLE GENOTYPE(S)
Procedure:
1. Your teacher will pass around 16 allele sacks. These contain the alleles that the mom
and dad bug could possibly carry according to their specific traits. The mom and dad
bug are not true-breeding for all of their traits, so there are many different combinations
possible for each baby bug.
2. Choose one allele card from each sack (no peeking!), then pass the sack on to the next
group.
3. Lay all 16 alleles out on your table and match up the pairs of letters.
4. Record the alleles your baby bug has received, the genotype, and the phenotype of your
baby bug in the table below. When writing the genotype, remember that the dominant
allele should be written first. Be sure to use the correct letter for each trait. You can find
out which letters to use and which alleles are dominant and recessive by looking at the
table on page 77 of your textbook.
TRAIT
“MOM”
ALLELE
“DAD”
ALLELE
BABY
GENOTYPE
BABY PHENOTYPE
Antennae Color
# of Body Segments
Tail Shape
# of Leg Pairs
Nose Color
Foot Color
# of Eyes
Gender
5. After you have filled out the table above, carefully put your allele cards back in the
sacks. Please make sure you put each allele in the correct sack so they will not be
mixed up for future classes!
6. Now that you know what your baby bug will look like, you are ready to build it! Using
your table as a guide (look at the “phenotype” column), carefully choose the items you
need to build your bug from the supplies on the front table. Here are some tips to
remember:
a. Get enough marshmallows for the # of body segments plus one for the head (and
no, you may not eat them!).
b. Use the green and red toothpicks for antennae ONLY – use other colors for the
legs and to attach the body segments and head together.
c. You may use glue to help hold the body together if necessary and to attach the
eyes.
d. Break or cut the toothpicks in half to make the antennae – this means you will
only need ONE red or green toothpick.
Analyze the Results:
7. Take a class poll of the traits of the offspring by putting a tally mark next to your baby
bug’s traits in the table on the SmartBoard. Record the results of the entire class in the
table below. What are the ratios of each trait?
Traits of the Offspring (class totals)
DOMINANT TRAIT
# BABIES
EXHIBITING
DOMINANT
TRAIT
RECESSIVE
TRAIT
Red Antennae
Green Antennae
3 Body Segments
Curly Tail
2 Body
Segments
Straight Tail
3 Leg Pairs
2 Leg Pairs
Blue Nose
Green Nose
Green Feet
Red Feet
2 Eyes
3 Eyes
# BABIES
EXHIBITING
RECESSIVE
TRAIT
Gender
Boy Babies
Girl Babies
RATIO OF
DOMINANT TO
RECESSIVE
TRAITS
Draw Conclusions:
8. Do any of the baby bugs look exactly like their parents? ______________
Explain your
findings. __________________________________________________________________
_________________________________________________________________________
9. Was this an example of selective breeding? ________________________ Explain your
answer. ______________________________________________________________
_________________________________________________________________________
Going Further:
10. Your little baby bug has grown up quickly. It is now time for him/her to find a mate and
have a baby of their own! Remember that you need to find a mate of the correct gender so
your baby bug can successfully reproduce. Depending on the number of male and female
bugs in your class this may mean that some bugs have to “mate” with more than one other
bug. If this happens to your bug you only need to record the results for one of his/her
partners. Record the data for your bug, your bug’s partner, and the possible genotypes and
phenotypes of their offspring in the table below.
* You will need to create Punnett Squares for each trait in order to
determine the possible genotypes and phenotypes! *
TRAIT
OUR BUG
Genotype
Antennae
Color
# of Body
Segments
Tail Shape
# of Leg Pairs
Nose Color
Foot Color
# of Eyes
Gender
Phenotype
PARTNER BUG
Genotype
Phenotype
POSSIBLE
GENOTYPES OF
OFFSPRING
POSSIBLE
PHENOTYPES OF
OFFSPRING
11. Now you need to draw a pedigree for the bug family that your class has created. You are
going to make a pedigree for the trait of antennae color. Some information you will need to
know before you draw your pedigree is:
a. What color antennae do the original “mom” and “dad” bugs have? (First Generation)
b. How many babies did the original “mom” and “dad” bugs have? (2nd Generation)
c. How many of the second generation bugs were boys? Girls?
d. Which color antennae does your baby bug have, and which color did his/her partner
have?
e. What possible genotypes/phenotypes for antennae color could your baby and his/her
partner’s children have?
f. Assume your baby and his/her partner had 4 children. Include these 4 children on the
pedigree. (3rd Generation)
Draw your pedigree in the space below:
Review Questions:
1. What is an “allele”? ______________________________________________________
______________________________________________________________________
2. What does “true-breeding” mean? ___________________________________________
______________________________________________________________________
3. What does “hybrid” mean? ________________________________________________
______________________________________________________________________
4. What process was simulated when you randomly picked alleles from the mom and dad
and matched them with one another? ________________________________________
5. What are the matching pairs of chromosomes in your new baby called?
______________________________________________________________________
6. What was the only sex chromosome that the mom bug could pass on? ______________
7. Which sex chromosome did the dad bug pass on to your baby bug? ________________
8. Is your baby bug a boy or a girl? _________ How do you know? __________________
______________________________________________________________________
9. What is a “genotype”? ____________________________________________________
______________________________________________________________________
10. What is a “phenotype”? ___________________________________________________
______________________________________________________________________
11. What type of letter represents a dominant allele? ______________________________
12. What type of letter represents a recessive allele? ______________________________
13. What is a Punnett Square? ________________________________________________
______________________________________________________________________
14. What is a Pedigree? _____________________________________________________
______________________________________________________________________