1Utah Agriculture in the Classroom

Objectives

1. Students will understand how some traits are always expressed

when passed from parent to offspring.

2. Students will understand that some traits are not always

expressed when passed from parent to offspring.

3. Students will be able to identify similarities and variations in

physical traits expressed by offspring of a parent plant.

Rock, Paper, ScissorsInvestigating traits that are always seen when

passed from parents to offspring

Time: 90 minutes (can be split

into two class periods)

Grade: 5

Core Standard:V- Students will understand that

traits are passed from the parent

organisms to their offspring, and

that sometimes the offspring may

possess variations of these traits

that may help or hinder survival in

a given environment.

Objective 1- Using supporting

evidence, show that traits are

transferred from a parent

organism.

Intended Learning

Outcomes:Students will know and explain

science information specified for

the grade level; record data;

describe or explain observations

carefully and report with pictures;

understand the nature of science;

and cite examples of how science

affects life.

Background

The Father of Genetics, Gregor Mendel, was born in 1822. He

was born into a peasant family and later entered into a monastery in

Brunn (a city in the southeastern part of the Czech Republic), where

he received an education. The great work that Mendel did in the quiet

monastery garden was ignored until after his death in 1885. His

work marked the beginning of modern genetics. Mendel’s major

contribution was to demonstrate that inherited characteristics are

carried as discrete units in each generation. These units came to be

known as genes.

Genes are the basic units capable of transmitting characteristics

from one generation to the next. A trait becomes the genetically

determined characteristic or quality that distinguishes one from

another. When an offspring is formed, its traits are determined by a

combination of genes from each parent. Each parent contributes

one half of the genes for each trait. In the simplest cases, genes are

either always expressed (dominant) or not always expressed

(recessive). When a dominant gene combines with a recessive gene,

the dominant gene’s characteristics are expressed in the offspring.

When two recessive genes are combined, the recessive characteristic

is expressed in the offspring. Co-dominance occurs when the genes

for a particular trait are equally strong. In this case, the two

variations of the gene are expressed in equal strength (e.g., red vs.

white= pink).

Gregor Mendel studied yellow and

green pea plants to determine

which traits were always

expressed when passed from

parent plants.

Materials

“Rock, Paper, Scissors” Recording Chart, one for each pair of

students

“Plant Feature Page,” one for each student

Crayons and scissors for each student

“What Does It Look Like?” activity sheet for each student

5 “Gene Pool” boxes made from shoe boxes (labeled leaves, fruit,

flowers, roots, and stems)

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Questions for

Investigation or

Assessment

1. Why would dominant

traited plants be more

readily available in the

grocery store? What

would a farmer need to

do in order to grow a

crop that exhibited only

recessive traits? Do you

think this would cost him

more or less money?

Mendel conducted his work with pea plants because they were

readily available and easy to cultivate. Different varieties had different

characteristics. He started with 32 types of pea plants which he

studied for about two years. He wanted to see which

characteristics were clearly defined. The results of these experiments

were called dominant traits and recessive traits by Mendel.

He continued with various experiments until his death in 1864.

Mendel’s work was first reported in 1865 to a small group of people

at the Brunn Natural History Society. Sadly, no one seemed

interested in what Mendel was talking about. It wasn’t until 1900 that

Mendel’s work was discovered by three other scientists working

independently of each other. Mendel’s brilliant analysis of the

questions they sought to answer, the design of his experiments, and

the clarity of his results are so outstanding that his name is

permanently linked with the first principles of genetics.

In agriculture there are many examples of dominant, recessive

and co-dominant traits. Many of the foods we enjoy every day have

been bred to look, taste, grow and develop using the principles that

Mendel first discovered. Some examples are listed. Perhaps you

have noticed that the dominant-traited plants are easier to find in

your grocery store.

* Red potato skin is dominant over white potato skin.

* Russet colored potato skin is dominant over white potato skin.

* Green peas are dominant over yellow peas.

* Red cherry tomatoes are dominant over yellow cherry

tomatoes.

* Red and white snapdragon flowers are co-dominant and

produce pink flowers.

* Short and tall corn plants are co-dominant and produce

medium height corn plants.

* Tall sunflower plants are dominant over short sunflower plants.

* Yellow kerneled corn is dominant over white kerneled corn.

Activity Procedures

1. Have students list words that are associated with the words

“dominant” (dominated, dominating, dominate, domain,

dominance, predominant, dominator, etc.) and “recessive”

(recessively, recede, receded, receding, recessional, recession,

etc.). Then, discuss the differences between the concept of

dominating a situation and receding in the same situation. For

instance, if two people wanted to climb up the ladder of a slide at

the same time, one person might dominate the situation by

yelling it was his turn or pushing someone out of the way to go up

first. Someone else might recede by walking away and playing

something else. The receding person may play at the slide later

when there is less competition (similar to genes!). Role play a few

situations such as lining up after recess or participating in class

discussions.

2. Describe the game Rock, Paper, Scissors using the words

“dominant” and “recessive.” Discuss that rock dominates

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scissors, scissors dominate paper and paper dominates rock.

Have the students play this game with a partner, recording their

outcomes on the “Rock, Paper, Scissors Recording Chart.” The

outcome column will say either “Rock,” “Paper,” “Scissors.” If

both people choose the same item then it is a tie and the item that

both people chose will be written in the outcome box. The

procedure for playing the game is described below.

To Play Rock, Paper, Scissors:

After a count of “1-2-3,” each player must symbolize a rock,

scissors or paper with one hand on a desk or table top. The

hand symbol for rock is a fist. The hand symbol for scissors

is the first two fingers cutting the air in a scissors motion.

The hand symbol for paper is a flat hand on the desk top or

table top. It is important that both players reveal their chosen

hand symbols at exactly the same time.

3. Discuss the outcome of the game. Are there ways of making

certain one person will always dominate (win)?

4. Discuss “dominant” and “recessive” in terms of genes and

heredity using some of the ideas given in the background

information.

5. Have each partnership color and cut out a “Plant Feature Page.”

Place the features into the appropriate gene pool containers (shoe

boxes) labeled “Leaves,” “Fruit,” “Flowers,” “Roots” or “Stems.”

Each partnership will contribute a dominant and recessive trait for

each feature. Place the five boxes in different locations through-

out the room.

6. Hand out, to each pair of students, the “What Does It Look Like?”

page. From the five separate “gene pool” containers have each

student randomly select one feature. Have the students fill in the

gene chart as each feature is chosen. The partners then need to

determine what their plant looks like. For example, if one partner

chooses a dominant round fruit and the other partner chooses a

recessive oval fruit, the plant will have round fruit. Have the

students complete their plant by drawing the appropriate features

on their plant.

7. Have the students display their plants. Discuss how many

dominant traits were expressed compared to recessive traits

(students should easily see that there were more dominant traits

Teacher Notes:

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Teacher Notes:

expressed than recessive traits). Discuss the wide variety of

plants produced from the same gene pool and how this activity

shows that it would be highly unlikely for two plants to be exactly

alike. Impress upon students that it is because of dominant and

recessive traits that certain characteristics may only appear in

select generations (why a child may have blue eyes like their

grandmother, but neither of the child’s parents has blue eyes).

Extensions/Adaptations/Integration

1. Have the students design their own dominant and recessive

features for the gene pool, perhaps adding some co-dominant

traits. Have them create the offspring with modeling clay.

2. Display pictures of parent plants along with four different pictures

of possible offspring. Have the students select which offspring is

most appropriate based upon a list of dominant and recessive

traits given by the instructor. Students should be able to justify

their answer.

Additional Resources

Lesson adapted from materials available from the California

Agriculture in the Classroom. Visit their web site for more

information: www.agclassroom.org/ca

Materials Adapted by the Utah Agriculture in the Classroom, www.agclassroom.org/ut

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Rock, Paper, Scissors Recording Chart

Name

Date

Possible Outcomes:

* Rock dominates scissors * Scissors dominates paper * Paper dominates rock

1) Which outcome was most common in your partnership?

2) Which outcome was the least common?

3) Were your results similar to the results of the class?

4) Describe one thing you learned about heredity by doing this activity.

Round Partner A Partner B Outcome(Rock, Paper, Scissors)

1

2

3

4

5

6

7

8

9

10

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What Does It Look Like?

Name

Date

Complete this plant diagram by following the instructions of your teacher.

Plant Diagram

Features Partner A Partner B Outcome

Leaf

Fruit

Flower

Stem

Root

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