Teacher Guide: Fast Plants® 1 – Growth and Genetics
Learning Objectives
Students will …
 Observe the life cycle of Wisconsin Fast Plants®, from seed to mature seedpod.
 Use a “bee stick” to pollinate Fast Plants.
 Design experiments to test the effects of water, light, and crowding on Fast Plants.
 Observe Fast Plants traits for stem color and leaf color.
 Identify dominant and recessive alleles for stem and leaf color.
 Use Punnett squares to predict the percentages of different offspring genotypes and
phenotypes, then test these predictions using the Gizmo.
Vocabulary
allele, dominant allele, Fast Plants, gene, genetics, genotype, heterozygous, homozygous,
offspring, phenotype, pollen, pollinate, Punnett square, recessive allele, trait
Lesson Overview
The Fast Plants® Gizmos were created as a collaboration
between ExploreLearning and the Wisconsin Fast Plants
Program of the University of Wisconsin-Madison. They were
designed to support the experiments that students can do
using Fast Plants seeds and plants. By using these Gizmos
in combination with growing Fast Plants, students can
compare simulated growth, development and reproduction
with firsthand observations of living Fast Plants.
The Student Exploration sheet for Fast Plants 1 – Growth and Genetics contains three activities:

Activity A – Students learn about the life cycles of Fast Plants (flowering plants) and
experiment with different growing conditions.

Activity B – Students make observations of how stem and leaf color traits in Fast Plants
are passed from parent to offspring plants.

Activity C – Students learn about the underlying genetics that regulate stem and leaf
color, then use Punnett squares to predict the ratios of traits in offspring.
Suggested Lesson Sequence
1. Pre-Gizmo activities
( varies)
The best way to prepare for the Fast Plants 1 Gizmo is to grow Wisconsin Fast Plants®
in the classroom. Fast Plants grow from seed to flowering in just two weeks, under
standard growing conditions. Complete information about growing Fast Plants is
available on the Program’s website: www.fastplants.org, and seeds are available from
Carolina Biological Supply®. To replicate some of the experiments in the Gizmo,
students can grow Purple and Non-Purple Stem, and Yellow-Green Leaf varieties of
Wisconsin Fast Plants Plants. Students can then use “bee sticks” or other tools to
pollinate their living plants, produce seedpods, and harvest the mature seeds.
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It is helpful for students to understand the basics of Mendelian genetics and the use of
Punnett squares prior to using this Gizmo. The Mouse Genetics (One Trait) and Mouse
Genetics (Two Traits) Gizmos would be great preparation.
2. Prior to using the Gizmo
( 10 – 15 minutes)
Before students are at the computers, pass out the Student Exploration sheets and ask
them to complete the Prior Knowledge Questions. Discuss student answers as a class,
but do not provide correct answers at this point. Afterwards, if possible, use a projector
to introduce the Gizmo and demonstrate its basic operations.
3. Gizmo activities
( 15 – 20 minutes per activity)
Assign students to computers. Students can work individually or in small groups. Ask
students to work through the activities in the Student Exploration using the Gizmo.
Alternatively, you can use a projector and do the Exploration as a teacher-led activity.
4. Discussion questions
( 15 – 30 minutes)
As students are working or just after they are done, discuss the following questions:

What does a plant need to grow and reproduce, and how is this illustrated in the
Gizmo? [Plants need soil, light, and water to grow. In the Gizmo, the plants do
not grow if there is no water or light. For the plant to reproduce, the flowers must
be pollinated. In the Gizmo, plants that are not pollinated do not produce seeds.]

Why is a “bee stick” used for flower pollination? [Bees collect pollen on the hairs
that cover their bodies (setae) and in pollen baskets on their legs. A bee stick
consists of a dried bee or bee thorax (the "hairiest" part of a bee) on a toothpick.]

Suppose a heterozygous green leaf plant is pollinated with pollen from a yellowgreen leaf plant. What proportion of the offspring will have yellow-green leaves?
[About half. All offspring receive a ygr allele from the yellow-green parent. Half
the offspring receive YGR alleles from the green parent, forming YGR/ygr (green)
offspring. The rest receive ygr alleles, forming ygr/ygr (yellow-green) offspring.]

Suppose your classmate proposes that each plant had only one allele for each
trait. For example, a purple-stem plant would have just one ANL allele and a nonpuple (green) stem plant would have one anl allele. When the plants mate,
offspring plants only have the dominant ANL allele. What observation disproves
this theory? [In the Gizmo, the F1 generation all had purple stems, but some the
F2 plants had green stems. This shows that the recessive anl allele did not
disappear and must have been carried by the F1 plants.]
5. Follow-up activities
( varies)
If possible, obtain Fast Plants® seeds and grow the plants to replicate some of the
experiments shown in this Gizmo. In addition to the homozygous parent seeds (purple
stem/green leaf and non-purple stem/yellow-green leaf) there are F1 (ANL/anl, YGR/ygr)
and F2 (offspring of F1 plants) seed packs available.
The Fast Plants 2 – Mystery Parent activity is a follow-up to the Fast Plants 1 activities.
In this lesson, students will determine the genotype and phenotype of a mystery parent
based on the traits of offspring plants and the other parent plants. Students can then
complete challenges to design their own Fast Plant hybrids. Fast Plants 2 also offers an
opportunity for students to learn about and apply the chi-squared test.
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Scientific Background:
Brassica rapa and its subspecies have been selectively bred by humans for over 4,000 years.
Cultivars of Brassica rapa include the turnip, bok choy, and napa cabbage. Wisconsin Fast
Plants® are a rapid-cycling variety of Brassica rapa developed by Dr. Paul Williams at the
University of Wisconsin-Madison. By selectively breeding plants with shorter life cycles, after 20
years he was able to reduce the life cycle from 6 months to 5 weeks. Additional selective
breeding allowed various genetic traits in the plants to be isolated and studied. Today, these
plants are used for genetic research and as a teaching tool in classrooms all over the world.
In the Fast Plants 1 Gizmo, traits for stem color and leaf color are studied. The stem color is
determined by the presence or absence of anthocyanin, a purple pigment found in many plants
including blueberries, cherries, and red cabbage. The gene, “anthocyaninless,” is named after
the recessive trait of producing no anthocyanin. The two alleles are ANL, which produces
purple-stemmed plants, and anl, which produces non-purple, or green-stemmed plants.
For leaf color, the gene also is named after the recessive trait: yellow-green leaves. Plants with
the dominant YGR allele have the standard, dark green leaves, while those with two copies of
the recessive ygr allele have yellow-green leaves. (Note: Students are usually taught that allele
symbols are based on the dominant allele. In fact, most allele symbols are based on the less
common, or “mutant” allele. If this allele is recessive, the symbol is based on the recessive trait.)
To predict the offspring of a
dihybrid (two traits) cross, use an
expanded Punnett square. The
sides of the square show the
possible allele combinations
contributed by each parent. The
boxes in the square show the
proportion of offspring that will
inherit that allele combination.
For example, the Punnett square at
right shows the possible offspring
of an ANL/anl, YGR/ygr plant and
an ANL/anl, ygr/ygr plant. Based on the Punnett square, you could predict that about 6 of 16
offspring (37.5%) will have purple stems and yellow leaves. You could also predict that about 2
of 16 offspring (12.5%) will have green stems and green leaves.
Selected Web Resources
Wisconsin Fast Plants: https://fastplants.org/
Fast Plants inheritance: https://fastplants.org/category/fast-plants-inheritance-blog/
Carolina Biological Supply (source for Fast Plants seeds): https://www.carolina.com/
Mendelian genetics: https://www2.palomar.edu/anthro/mendel/mendel_1.htm
Dihybrid cross: https://www.ndsu.edu/pubweb/~mcclean/plsc431/mendel/mendel3.htm,
http://www.biology.arizona.edu/mendelian_genetics/problem_sets/dihybrid_cross/03t.html
Growing Plants Gizmo: https://www.explorelearning.com/gizmo/id?635
Pollination: Flower to Fruit Gizmo: https://www.explorelearning.com/gizmo/id?615
Mouse Genetics (One Trait) Gizmo: https://www.explorelearning.com/gizmo/id?449
Mouse Genetics (Two Traits) Gizmo: https://www.explorelearning.com/gizmo/id?382
Fast Plants 2 – Mystery Parent Gizmo: https://www.explorelearning.com/gizmo/id?1087
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