Classroom Interactions: Explorations in
Mathematics and Science Teaching
Title of Lesson: Mendel’s Laws and Punnett Squares!
UFTeach Student’s Name: Nicole Steele
Teaching Date and Time: Monday, October 22nd, 2012 8:30-9:20am
Length of Lesson: 50 minutes
Grade / Topic: 10th Grade Honors Biology
Source of the Lesson: All of my sources are either made up by me or come from the Internet. The engagement
YouTube video is from http://www.youtube.com/watch?v=aDpLDBaEBjk and I created the worksheet by
myself, with a little inspiration from http://www.exploringnature.org/db/detail.php?dbID=22&detID=2289. The
first evaluation question is from www.cpalms.org under the sample test questions for SC.912.L.16.1.
Appropriateness for High School Students: An engaging and educational video is used to begin the lesson
and to help students become interested and educated in the topic for the day’s lesson. Questions are asked all
throughout the engagement to the evaluation in order to help students think outside the box and address
misconceptions. Probing questions are also used to allow students to think in a deeper manner and begin to
explore the topic more.
Concepts
Gregor Mendel was a monk who crossed peas in order to study heredity. He realized that, when crossing a
round pea with a wrinkled pea, the offspring was round, rather than a mixture of round and wrinkled. During the
next generation of offspring, he found that the peas were wrinkled, even though both the parents were round
peas. From this, Mendel learned about dominant and recessive traits, and how they are passed on through the
generations. The law of segregation and the law of independent assortment aid in assisting us today in finding
patterns of inheritance. Also, not all traits follow Mendel’s inheritance patterns that are described in this lesson.
Such examples are incomplete dominance, codominant heredity, etc. The law of segregation states that
organisms inherit one allele from each parents and that gametes carry one allele for each trait. The law of
independent assortment states that the inheritance of one trait does not have an affect on the inheritance of
another trait. Lastly, theories and laws are discussed for this lesson. Theories are tested and explain phenomena
while laws are simply observations that do not have any evidence.
Source: http://www.ndsu.edu/pubweb/~mcclean/plsc431/mendel/mendel1.htm
Florida State Standards (NGSSS):
 Grades 9-12, SC.912.L.16.1 Big Idea: Science-Heredity and Reproduction-Use Mendel’s laws of
segregation and independent assortment to analyze patterns of inheritance. Complexity: Moderate
 Grades 9-12, SC. 912.N.3.4 Big Idea-Nature of Science-Recognize that theories do not become laws, nor
do laws become theories. Theories are well-supported explanations and laws are well-supported
descriptions. Complexity: Moderate
Performance Objectives
 Students will be able to explain Mendel’s laws of segregation and independent assortment by discussion
and completion of the Punnett square worksheet
 Students will be able to identify patterns of inheritance through Mendel’s laws and the completion of
Punnett squares
 Students will be able to identify the differences between theories and laws through discussion of
Mendel’s laws
Classroom Interactions: Explorations in
Mathematics and Science Teaching
Materials List and Student Handouts
 24 student nametags
 Heredity video from YouTube http://www.youtube.com/watch?v=aDpLDBaEBjk
 24 copies of the exploration worksheet (1 for each student)
 PowerPoint presentation
 24 copies of assessment (1 for each student)
Advance Preparations
 Student nametags should be handed out to students as they enter the classroom
 The PowerPoint should be set up on the computer prior to the lesson
 Teacher should convert YouTube video to QuickTime Player using zamzar.com or another program and
have it set up before the lesson
 Exploration worksheet and evaluations should be organized in a way so the teacher can easily hand them
out at specific times during the lesson
Safety
 There are no significant safety concerns for this lesson
5E Lesson Templates
ENGAGEMENT
What the Teacher Will
Do
-The teacher will greet the
class and explain the
objectives of the lesson
Time: 5 minutes
Teacher Directions and Probing Questions Student Responses and
Potential
Misconceptions
-Good morning! My name is Ms. Steele and today
we will be learning of a very famous scientist in
the field of biology. Raise your hand if you have
-Some students should have
ever heard of Gregor Mendel.
at least heard of him and
raise their hands
-What did Mendel accomplish in his lifetime as a
scientist?
-The teacher will show
students the video and ask
-I’m not sure; something to
do with genetics [he crossed
pea plants and came up with
the laws of segregation and
independent assortment. He
identified dominant and
recessive traits and was able
to predict traits]
-Today we are going to learn about Mendel and
his laws of segregation and independent
assortment.
-Our goal for today is to understand the patterns of
inheritance and we are going to predict traits today
as well!
-In order to understand Mendel and his laws, I
-Students should be
would like you to please watch this video quietly. respectfully and quietly
Classroom Interactions: Explorations in
Mathematics and Science Teaching
them to make observations
while watching it.
Make mental notes of any information that is new,
interesting, or weird to you.
watching the video and
making observations.
http://www.youtube.com/watch?v=aDpLDBaEBjk
-The teacher will ask
students questions about
the video
-Turn to your shoulder partner and share with
him/her one new piece of information you learned
from the video. I will give you one minute to
discuss your observations with your partner.
-Students will share their
new observations with their
shoulder partners and, after
that, with the class.
-[I learned Gregor Mendel
was a monk and that he
experimented a lot with peas.
I learned that, when he
crossed a wrinkled pea with a
round pea, he expected the
pea to be a cross between the
two, rather than the pea
turning out round like it did.]
-What is one interesting thing you learned from
the video?
-The teacher will transition
into the exploration
-I would like you to please turn to your shoulder
partner once again and discuss this question: What
do you believe Bill Nye meant when he stated
“segregation”? How does that relate to the law of
segregation we are going to learn about today? I
will give you one minute to discuss this with your
partner.
-Now that you have discussed it with your partner
we will talk about it as a class. What do you think
Bill Nye meant by “segregation”? Relate it to
Mendel’s pea crossings.
-Now that we have an understanding of Mendel
we are going to further explore heredity.
EXPLORATION
What the Teacher Will Do
-The teacher will introduce the
exploration activity to the class.
Teacher Directions and
Probing/Eliciting Questions
-For today’s lesson I have a fun
activity. However, in order to
complete it successfully, we need
to go over a few key concepts.
-To begin with, Mendel was able to
predict heredity. We use Punnett
squares in order to do so.
-Certain characteristics
disappear in the first
generation and appear during
the second. [Allele pairs
segregate during gamete
formation and randomly
unite again at fertilization]
Time: 20 minutes
Student Responses and
Misconceptions
Classroom Interactions: Explorations in
Mathematics and Science Teaching
-The teacher will ask questions in
order to help students understand
key concepts
-What is a Punnett square?
-The teacher will have an example
of a Punnett square on the board
and fill it out for the students
-I have a blank Punnett square for
tongue rolling that I am going to
show you how to complete.
-The teacher will have a blank
Punnett square on the PowerPoint
on the board
-I have a blank Punnett square on
the board with two plants that are
bred together: tall plant (BB) and
short plant (bb).
-The teacher will call on a student
to complete the Punnett square on
the board
-[A Punnett square is a box divided
into four sections and is used to
predict an outcome of a particular
cross.]
-How would we define an allele
then?
-[One of two or more alternative
forms of a gene]
-What is the BB or bb called?
-[An allele]
-Since our activity involves
working with Punnett squares, I
want you all to be comfortable
completing one before I let you
work. I will select one student to
complete this blank Punnett square
on the board. The rest of the class
will help this student complete it.
-One student will complete the
Punnett square with the help of the
class.
-The letters or characteristics [the
genotype]
-Good! We were able to complete
the Punnett square! What would we
call the Bb, Bb, Bb, and Bb that we
ended up with?
-[The two genes in a pair]
-What is an allele?
-[The alleles of a genetic code (one
-What is a genotype?
maternal and one paternal]
-[Bb]
-What would be the genotype for
this Punnett square?
-What is a phenotype?
-Why would a plant with the
genotype Bb have a phenotype that
states the plant as being tall?
-The characteristics [the expressed
physical trait or also known as what
can be seen. The BB is tall plants
and bb is short plants]
-[Because of dominant and
recessive traits]
Classroom Interactions: Explorations in
Mathematics and Science Teaching
-What is a dominant phenotype?
-AA=Freckles
-aa=no freckles
-What phenotype would a person
with a heterozygous Aa have?
-Is AA or aa dominant?
-You will be working with your
shoulder partner for this entire
activity. I will pass out a worksheet
that you should try and complete.
Between you and your partner, you
will each turn in a paper. You have
roughly 15 minutes to complete it
with your shoulder partner. For this
activity, you will hypothetically
assume that you and your partner
are starting a family. You are
having a child and are trying to
predict what color eyes it will have,
what gender it will be, and how
straight/curly the hair will be. In
order to do so, make sure to read
the instructions carefully before
you begin. Since you and your
partner are the parents, the child
will be receiving its genes from
you. Therefore, if you are a girl,
have light hair, and have dark eyes,
make sure to use those genotypes.
-Any more questions before we
begin? Remember, I will be
walking around the classroom so
please do not hesitate to ask me any
questions. I understand this is a lot
of new material that can be difficult
to grasp at first. I am here to help
you!
-[A plant can be tall (B) if its
genotype if BB or Bb. A plant can
only be short if its genotype is bb.
If the plant has a B then it must be
dominant]
-[Freckles]
-[AA]
Classroom Interactions: Explorations in
Mathematics and Science Teaching
-The teacher will have the students
complete their exploration activity
and walk around the classroom,
helping students and asking guiding
questions.
-Make sure to read the instructions
carefully and, once again, feel free
to ask me any questions.
-What did we say a genotype is?
-How else could we say the word
“phenotype”?
-[The genetic code and the alleles]
-[Characteristics that we see]
-What do I mean by curly hair and
by wavy hair?
-[Curly hair is filled with curls.
Think Taylor Swift curls. Wavy
hair is not quite straight but it is not
super curly]
-Do you have a boy or a girl? How
do you know?
-[We are having a boy/girl because
it has XY/XX alleles.]
-Does your child have light or dark
eyes?
-[It has light eyes because its
genotype is bb/it has dark eyes
because its genotype is BB]
-[Curly because of HH or straight
because of hh]
-Does your child have curly or
straight hair?
-Why would a child with Hh have
curly hair and not just, wavy hair
for instance?
-[Because H is dominant so it will
be curly. Mendel thought that if
HH and hh crossed then the
outcome would be wavy hair.
However, it does not work like that
because H is a dominant
phenotype.}
-The teacher will transition into the
explanation.
-Now that we have completed the
activity, let’s share our findings
with the rest of the class!
EXPLANATION
What the Teacher Will Do
Time: 15 minutes
Teacher Directions and
Student Responses and
Probing/Eliciting Questions
Misconceptions
-Everyone has completed their
-A few students and their partners
worksheet and now knows what
will be called on and will share
their child with their partner would with the class what their children’s
possible look like. Can I have a few genotypes and phenotypes are.
“couples” share what their children
may look like? Make sure to share
its gender, eye color, and hair
characteristics. Choose the one that
-The teacher will have the students
share their findings with the class.
Classroom Interactions: Explorations in
Mathematics and Science Teaching
is the biggest percent. For instance,
if the baby has a 75% change of
having curly hair, then tell us that.
-The teacher will call on three
students and their partners that
have not yet participated. They will
go up to the board and complete the
blank Punnett square on the board
for their baby’s gender, eye color,
or hair. There will only be one
couple for each. The teacher will
have the students complete the
Punnett square and then tell the
class their baby’s genotype and
phenotype for gender, eye color, or
hair.
-The teacher will ask the students
questions and teach the students the
important concepts.
-Now that we know what some of
your classmates’ hypothetical
children may possible look like in
the future, let’s see how they
figured it out. Let’s have three
couples come up to the board and
show us how they predicted their
baby’s sex, eye color, and hair
waviness.
-What is a homozygous genotype?
-What is a heterozygous genotype?
-Dominant alleles will always show
while recessive alleles will only
show with other recessive alleles.
For example, BB and Bb would
show that a baby has dark eyes
while bb would show that a baby
has light eyes.
-For the explanation of the law of
-Why couldn’t you state your
segregation, the teacher can point at baby’s definite gender, eye color,
the student Punnett squares on the
or hair waviness?
board and where the students
placed the alleles to demonstrate
the law.
-What is Mendel’s law of
segregation?
-What is Mendel’s law of
independent assortment?
-[The alleles are the same (BB or
bb)]
-[The alleles are different (Bb)]
-[We could only calculate the
chances of the children having
certain characteristics because there
will still, no matter what, be
different possibilities depending on
the mother’s and father’s
genotypes.]
-[A pair of factors, known as
alleles, controls each gene. When a
gamete (or in this instance a baby)
is made, these alleles will separate.
In our Punnett square, we separated
the Bb into B and b for both
parents]
-[The inheritance of one trait has no
effect on the inheritance of
another.]
Classroom Interactions: Explorations in
Mathematics and Science Teaching
-Why do we strive to understand
Mendel’s inheritance patterns?
-The teacher will help students
identify the differences between a
law and a theory.
-How can a person’s phenotype
provide information about his/her
genotype?
-Do the laws of segregation and
independent assortment always
work?
-There are certain cases when the
two alleles have the same amount
of power or dominance, so to
speak.
-What do you think codominant
inheritance is?
-Why would this happen?
-What is incomplete dominance?
-Why does this happen?
-[They help us predict the
inheritance of traits]
-[If for example, a person could not
roll their tongue he/she would have
a genotype of rr, because it is a
recessive trait. If a person could
roll his/her tongue the genotype
would have to be dominant so it
would either have to be RR or Rr]
-Yes [No]
-[Two alleles of a heterozygote
gene pair both have full phenotypic
expression. Therefore, with Hh,
both would be shown.]
-[One allele for a specific trait is
not completely dominant over the
other allele. Therefore, a combined
phenotype arises. An example is
red and white snapdragon plants
producing offspring. The offspring
turned out pink, not red or white. ]
-Mendel came up with two major
laws that we just discussed.
-Can a theory become a law? Can a
law become a theory?
-Why not?
-[No]
-What is the difference between a
law and a theory?
-[Theories and laws are different.
Theories are proven while laws are
simply observations.]
-[A theory is a well-supported
Classroom Interactions: Explorations in
Mathematics and Science Teaching
explanation and laws are wellsupported descriptions. Theories
have been proven and have
evidence while laws are
observations. A law can predict
something happening but cannot
explain it]
-The teacher will wrap up the
explanation and transition into the
evaluation, or if time allows, the
elaboration.
-Now that we are experts on Gregor
Mendel, Punnett squares, theories
and laws, and heredity, I am going
to collect your papers and I want to
see how much you have learned
today by giving you a small
evaluation.
ELABORATION
What the Teacher Will Do
Time: None
Probing/Eliciting
Student
Questions
Responses and
Misconceptions
-The teacher will have the students complete a more complex
Punnett square that involves more traits. The Punnett square from
this website may be used:
http://biologycorner.com/worksheets/genetics_2traits_bio2A.html
-The teacher will have the student work with a partner. After the
students have completed it, they will go over it as a class.
-The teacher will transition into the evaluation.
EVALUATION
What the Teacher Will Do
-The teacher will hand each student
an assessment
-The teacher will announce that the
students have ten minutes to
complete the assessment on their
own
-The teacher will collect the
assessments after the ten minutes
are over
Assessment
1. Hemophilia is a sex-linked,
recessive trait. Which of the
following describes the probability
of hemophilia in the offspring of a
man who does not have hemophilia
and a woman who is a
heterozygous carrier?
A. There is a 100% chance that
their sons will have hemophilia.
B. There is a 0% chance that their
daughters will have hemophilia.
C. There is a 25% chance that their
sons will have hemophilia.
D. There is a 50% chance that their
daughters will have hemophilia.
Time: 10 minutes
Student Responses
1. B. There is a 0% chance that
their daughters will have
hemophilia.
Classroom Interactions: Explorations in
Mathematics and Science Teaching
2. Using what we learned in class
today, why are Mendel’s
discoveries referred to as laws and
not as theories? Support your claim
with at least two reasons.
3. Two plants are crossed in an
experiment. The plants have
genotypes of Tt and Tt, with T
representing tall plants and t
representing short plants. Complete
the Punnett Square and write the
possible genotypes and phenotypes
of the possible offspring.
2. Mendel’s laws of segregation
and independent assortment are
named so because they describe
behavior. They are observations
and cannot be turned into theories
because theories are proven and
tested.
3. Genotypes: TT, Tt, tt
(25% TT, 50% Tt, 25% tt)
Phenotypes: Tall, short
(70% tall-the TT and Tt and 25%
short-the tt)
Classroom Interactions: Explorations in
Mathematics and Science Teaching
Name: __________________________________________
Partner’s Name: __________________________________________
Our Child
For this activity, you will be working with a partner. You and your partner are expecting a child and are
wondering what its gender, eye color, and waviness of hair will be. In order to do so, you must reflect on yours
and your partner’s genotypes, since the baby will inherit its traits from its parents. For eye color, we are going
to assume that everyone will either be bb or BB, rather than Bb, which gets confusing.
SEX
If you are a female then your genotype is XX
If you are a male then your genotype is XY
What is your genotype? _________________
What is your partner’s genotype? ___________________
Write your genotype above the top two boxes
Write your partner’s genotype on the left side of the two top and bottom left boxes
What are your baby’s possible genotypes?
What is your baby’s phenotype? (25%, 50%, 75%, 100%
chance of baby having….)
EYE COLOR
If you have light eyes then your genotype is bb
If you have dark eyes then your genotype is BB
What is your genotype? __________________
What is your partner’s genotype? _____________________
Write your genotype above the top two boxes
Write your partner’s genotype on the left side of the two top and bottom left boxes
Classroom Interactions: Explorations in
Mathematics and Science Teaching
What are your baby’s possible genotypes?
What is your baby’s phenotype? (25%, 50%, 75%, 100%
chance of baby having…..)
HAIR
If you have curly hair then we will assume your genotype is HH
If you have straight hair then we will assume your genotype is hh
What is your genotype? _________________________
What is your partner’s genotype? _________________________
Write your genotype above the top two boxes
Write your partner’s genotype on the left side of the two top and bottom left boxes
What are your baby’s possible genotypes?
What is your baby’s phenotype? (25%, 50%, 75%, 100%
chance of baby having…..)
Overall, what do you think your baby will look like?
________________________________________________________________________________
Classroom Interactions: Explorations in
Mathematics and Science Teaching
Name: _________________________________________
Evaluation
1. Hemophilia is a sex-linked, recessive trait. Which of the following describes the probability of hemophilia in
the offspring of a man who does not have hemophilia and a woman who is a heterozygous carrier?
A. There is a 100% chance that their sons will have hemophilia.
B. There is a 0% chance that their daughters will have hemophilia.
C. There is a 25% chance that their sons will have hemophilia.
D. There is a 50% chance that their daughters will have hemophilia.
2. Using what we learned in class today, why are Mendel’s discoveries referred to as laws and not as theories?
Support your claim with at least two reasons.
3. Two plants are crossed in an experiment. The plants have genotypes of Tt and Tt, with T representing tall
plants and t representing short plants. Complete the Punnett Square and write the possible genotypes and
phenotypes of the possible offspring.
Genotypes: ________________________________
Phenotypes: ________________________________