2. Understanding Inheritance
• A farmer who raises vegetables wants to cross two
types of corn plants. One type is a homozygous plant
with red kernels (RR) and the other is a homozygous
plant with white kernels (rr). For these plants, red
color is dominant and white color is recessive. Fill in
the Punnett square below to predict the offspring the
farmer should expect.
• Draw and drop the correct allele combinations into
the Punnett square to answer the question. There are
more choices available than will be used to solve this
Punnett square.
RR RR
RR RR Rr Rr
Rr Rr rr rr
rr rr
r r
R R
r
R
r
R
3. Understanding Inheritance
• Using your Punnett square from the previous slide, predict the color of the
corn kernels. Will the plants produce all red kernels, all white kernels, or a
mixture of both colors?
• What would be the ratio of red corn to white corn in the offspring?
4. Understanding Inheritance
• Next, the farmer cross-pollinates the red hybrid
(Rr) offspring. Complete the Punnett square
below for this cross.
• Draw and drop the correct allele combinations
into the Punnett square to answer the question.
There are more choices available than will be
used to solve this Punnett square.
RR RR
RR RR Rr Rr
Rr Rr rr rr
rr rr
r r
R R
r
R
r
R
5. Understanding Inheritance
• Using your Punnett square from the previous slide, predict the color of the
corn kernels. Will the plants produce all red kernels, all white kernels, or a
mixture of both colors?
• What would be the ratio of plants with red kernels to plants with white
kernels in the offspring?
6. Reader’s Theater-An Interview with Gregor Mendel
CHARACTERS: Reporter, Gregor Mendel
Reporter: Good evening. Tonight we have a special guest in our studio. His name is Gregor Mendel. Mr. Mendel was an Austrian friar and a scientific researcher more
than 150 years ago. He traveled in a time machine to get to our interview today. Thank you for coming.
Gregor Mendel: It was a long journey, but I’m glad to be here.
Reporter: Our viewers are interested to hear about how your study of peas changed the way we view heredity.
Gregor Mendel: I’m glad to hear that my work is important. I started my research in the 1850s.
Reporter: I have some questions I’d like to ask you, if you don’t mind.
Gregor Mendel: No, I don’t mind. Ask any question you’d like.
Reporter: My first question concerns your choice of plants. Why did you use pea plants?
Gregor Mendel: Pea plants grow and reproduce quickly, so I was able to breed many plants in a short period of time. Also, they have a wide variety of traits, or
characteristics, so I was easily able to record the results of the cross-pollination of different varieties. I studied many generations of pea plants to reach my
conclusions. My colleagues at the monastery used to grumble because we ate so many peas.
Reporter: Now I understand why you used peas. Can you describe cross-pollination?
Gregor Mendel: I transferred pollen from the flowers on certain plants to the flowers on other plants. For example, I transferred pollen from short-stemmed pea
plants to other short-stemmed pea plants. I noted that the offspring from this combination were always short-stemmed, just like the parents. When I crossed tall-
stemmed plants with other tall stemmed plants, however, I noted that tall and short plants grew. To me, this meant that the short-stemmed trait must be present
somewhere in the genetic makeup of the tall stemmed pea plants.
Reporter: And for those of us who don’t have a background in genetics, what did you conclude from your experiments?
7. Reader’s Theater-An Interview with Gregor Mendel
Gregor Mendel: I determined that each parent pea plant must contain two characteristics for a particular trait. When two plants with different traits, such
as tall and short stems, were bred, the offspring showed only one of the traits. This was then called the dominant trait, and the trait that did not appear was called
recessive.
Reporter: How do you think the traits are inherited?
Gregor Mendel: From the evidence I gathered in my research, I concluded that each parent contributes one factor to the plant in the offspring generation. So, the
offspring in the first filial generation gets one factor from the female parent and one factor from the male parent. The two factors interact to produce the resulting
trait.
Reporter: Why is this called the study of heredity? What was it about your experiments that changed the way we look at heredity today?
Gregor Mendel: Until the time I conducted my research, people believed that the blending of traits resulted when two complex life-forms such as plants reproduced. I
disproved that hypothesis by crossing two different flower colors, for example. I never saw a mixture of purplish-white flowers on a plant. The result was always
purple or white.
Reporter: Can you give us an example with humans?
Gregor Mendel: Sure. Some people have unattached earlobes; that is, a part of the lobe hangs down from the side of the head. This is a dominant trait. The recessive
trait is an attached earlobe. The lower part of this type of earlobe attaches directly to the side of the head. If a person’s mother has attached earlobes and the father
has unattached earlobes, then the person will have attached or unattached earlobes, but not something in between. Not all traits follow such simple patterns of
inheritance, but some do.
Reporter: Well, we hope you are aware that your work is important to the scientific community, although not everyone recognized your findings during your time. By
1900 your work was recognized as important to the world of biology, specifically to the study of genetics. Thanks again for your time this evening. We are fortunate to
have had this opportunity to speak with you, Mr. Mendel. Have a pleasant trip back through history.
8. Reader’s Theater-
An Interview with Gregor Mendel
• Part A- Choose the best response
by deleting all incorrect choices.
• Which statement describes Mendel’s
importance as a scientific researcher?
A) Mendel created a machine that
allowed for time travel
B) Mendel conducted research in various
scientific areas over 150 years ago
C) The area of biology was impacted by
Mendel’s research on genetics
D) The study of pea plants changed how
we grow flowers
• Part B-Choose the best response by
deleting all incorrect choices.
• Which statement from the passage
supports the response from Part A?
A) Pea plants grow and reproduce quickly
B) Parent pea plants must contain two
characteristics for a particular trait
C) Mendel was an Austrian friar and a
scientific researcher
D) Not all traits follow such simple
patterns of inheritance, but some do.
9. Reader’s Theater-
An Interview with Gregor Mendel
• The reporter stated “Our viewers are interested to hear about how
your study of peas changed the way we view heredity.”
• How did Mendel’s study of peas change the way we view heredity?
Using the reporter’s interview provide two examples of how Mendel’s
study changed the way we view heredity. Make sure to support your
answer with evidence from the interview.
