Download Export To Word

Kingsnakes: Can Genetic Variation be
Advantageous in Changing Environments?
Resource ID#: 129193
Primary Type: Lesson Plan
This document was generated on CPALMS - www.cpalms.org
This role-playing activity will visually show students how genetic variation and environmental
factors contribute to evolution by natural selection and diversity of organisms. During this
activity, students will represent the alleles themselves! Students will "mate" to create various
genotypes and phenotypes through an engaging, fun, and content-enriched activity. Students will
use scientific and mathematical skills to complete and draw conclusions.
Subject(s): Science
Grade Level(s): 7
Intended Audience: Educators
Suggested Technology: Document Camera, Computers for Students, GeoGebra Free Software
(Download the Free GeoGebra Software)
Instructional Time: 80 Minute(s)
Resource supports reading in content area: Yes
Keywords: natural selection and variation, phenotype and genotype, incomplete dominance,
homozygous and heterozygous genes
Instructional Component Type(s): Lesson Plan, Learning Goal, Model Eliciting Activity
(MEA) STEM Lesson
Resource Collection: FCR-STEMLearn Diversity and Ecology
ATTACHMENTS
KingsnakesGeneticVariationStudentDataSheet.docx
LESSON CONTENT

Lesson Plan Template:
General Lesson Plan

Learning Objectives: What will students know and be able to do as a result of this
lesson?
1. Students will demonstrate knowledge of genotype and phenotype relationships by participating in an
activity and recording data.
2. Students will draw conclusions based on data that genetic variations (diversity) are advantageous for
species evolution.

Prior Knowledge: What prior knowledge should students have for this lesson?
1. Students should have knowledge of genotypes and phenotypes.
2. Students should have an understanding of dominant and recessive alleles.
3. Students should be able to record genotypes based on which alleles an organism has.
4. Students should have a basic understanding of mitosis and meiosis.
5. Students should have basic knowledge of co-dominance, incomplete dominance, homozygous dominate,
homozygous recessive, and heterozygous.

Guiding Questions: What are the guiding questions for this lesson?
1.
2.
How might low genetic diversity impact a population?
Is evolution occurring today?

Engage: What object, event, or questions will the teacher use to trigger the students'
curiosity and engage them in the concepts?
Pass out the student data sheet "Kingsnakes: Can genetic variation be advantageous in changing
environments?"
Ask students to answer the first question on their worksheet - What is genetic variation? Generate a class
discussion by asking for volunteers to share their ideas to the whole class. Answers may vary
from variation in genotype leading to variation in phenotype to genotypic variation leading to differences in
survival and reproductive success.
Watch the 12-minute YouTube video "Natural Selection - Crash Course Biology #14." Make sure to preload the video so ads are not shown to students. If time (or student engagement) is a concern, the movie can
easily be stopped in multiple locations.
After watching the video, have students address the second question on their data sheet "Think of a real
world example and describe it using complete sentences."
Ask students to share with a student sitting next to them. Then have a class discussion and ask for
volunteers to share their responses.
Teacher: "Today we are going to use our knowledge about genotypes and phenotypes to determine if
genetic variation is advantageous for species evolution during environmental changes. We will be
representing alleles for a color gene of kingsnakes. However, first lets learn a little about kingsnakes."
Read summary (taken from the resources written below- can include more information or take out
depending on teacher's preference). Posting an image of various kingsnake color patterns on the screen will
increase engagement.
Summary: The common kingsnakes are found throughout most of North America. Kingsnakes can be about
36-48 inches in length. There is even a subspecies called Lampropeltis getula floridana (Florida kingsnake)
that is found on the peninsula of Florida. Depending on the kind of kingsnake they are found in many
different types of habitats. Some of these include, pine forests, bottomlands and swamps, tidal wetlands,
lumber, in trash piles, barns, along stone walls, on sunny railroad embankments, in stump holes, and even
farmlands. Their physical appearance can be black and shinny, vibrant reds, yellows, oranges, tans, black
and white arranged in bands, rings, stripes, patches, spots and speckles, with the exact design depending on
the species. Kingsnakes may take on a color that helps tell predators they are dangerous. The common
kingsnake feeds on other animals that it can constrict like lizards, other snakes, frogs, birds, and turtles.
Some species of kingsnakes have a special enzyme that breaks down venom so it can also eat snakes like
copperheads and rattlesnakes! Kingsnakes mate in the spring and the female lays anywhere from 4-20 eggs.
They reach sexual maturity at about 4 years old and can live up to about 20 years!
Resources:
o
o
o
Desert USA: Common Kingsnake
Savannah River Ecology Laboratory: Eastern Kingsnake
Animal Diversity Web: Lampropeltis getula
Teacher: "For our activity, we will be pretending the color variation is due to three alleles: black, purple,
and white."

Explore: What will the students do to explore the concepts and skills being developed
through the lesson?
Before moving students outside:
0.
1.
Tell students to look at the chart on their data sheet titled "Allele Relationships for the Color
Gene." Explain that they will use this table to help them determine genotypes and phenotypes.
Hold up the colored bandanas and practice with students what the phenotype will be with various
allele combinations. Use vocabulary terms homozygous recessive, homozygous dominate, and
heterozygous to help students learn terms. See chart for details. Example: Black and purple
bandanas will equal a black snake. The genotype would be Bp, which is heterozygous.
Move students outside or to a large area:
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

Pass out colored bandanas, one per student. Try to keep the colors distributed as evenly as possible
(8 black, 8 purple, 8 white).
Tell students to tie their bandana on their arm. The bandanas (and each student) represent one
allele and when they "mate and procreate" they will combine to create a genotype and phenotype.
Have students gather in a "pool" (large area in a circle). Tell students they need to find a mate and
then lock arms to simulate creating an offspring (procreation). This will represent generation 1.
Once all students have mated and procreated, teacher will go around to each pair and ask students
what genotype should be recorded for their pair. Ex. Students with a purple-white (pw) bandana
combination will be red snakes.
Place results on large mobile dry erase board so all students can see and check their work.
Students will record total number of snakes for each genotype and phenotype on Table 1.1 for
each combination.
Tell students that the black, purple and red snakes were camouflaged and protected from
predators. The white snakes were very visible in the dark environment and were eaten by
predators.
All white snakes will be removed (die) from the "pool." These students should stand off to the side
and can take on the role of writing data on the dry erase boards and helping to count and record
data.
Have "surviving" students separate and join the "pool" circle as individual alleles. Students will
choose a new person and "mate" to make Generation 2.
Repeat step 3-10 for a 3rd and 4th generation. At the end of the 4th generation, do not remove the
white snakes.
After students have mated, tell students that a hurricane came through and knocked back the
succession of the forest habitat in which the kingsnakes live. Now the area is covered with white
sand and plants with red and purple flowers. The black snakes are now very visible to predators.
All black snakes need to be removed (die).
Have students record genotypes and phenotypes in the data table marked "After Hurricane."
Explain: What will the students and teacher do so students have opportunities to clarify
their ideas, reach a conclusion or generalization, and communicate what they know to
others?
Back in the classroom, students will answer the follow-up questions (optional: individual or partners). The
teacher can lead a class discussion about what the activity represented and what the data showed based on
the follow-up questions.
Follow-Up Questions Answer Key:
1. Can a black allele combined with a white allele and make a white snake? Explain.
Answer: No, a black allele would be dominate over the recessive white allele making a heterozygous gene
and the phenotype would be black.
2. Using the data from this activity, explain how genetic variation is advantageous for species survival.
Answer: The data should show a decrease in white snakes however, the recessive gene still runs through the
genotypes in the population. There is evidence that there is an evolutionary change through the genotype
and phenotype numbers. When the second environmental factor is applied (predators favored black snakes)
the decrease in black snakes occurs and the survivors are the heterozygous genotypes that survived because
of genetic variation.
3. What did the removal of the white and then the black snakes represent scientifically?
Answer: Natural selection
4. What is the big difference you noticed between generations 1-4 and after the hurricane?
Answer: The dominant gene B was reduced rapidly because of the environmental disaster and subsequent
natural selection pressures on that phenotype. The dominant gene produced a phenotype of black that was
easily spotted after the hurricane causing these snakes with this gene to die and therefore not pass on the B
(dominant gene).
5. What factors may cause dominant alleles to disappear quickly from a population?
Answer: Natural selective pressures acting on the dominant phenotype; low genetic diversity with an
environmental disaster.

Elaborate: What will the students do to apply their conceptual understanding and skills
to solve a problem, make a decision, perform a task, or make sense of new knowledge?
Introduce students to the Application Questions. This assessment can be completed as homework, or in
class throughout the week (provide access to computers), depending on time constraints.
Application Question Answer Key:
1. Think of a real-world example where lower genetic diversity has impacted a species. Please explain the
scenario in detail and use research to support and provide evidence in your response. Include citations for
research. This should be a typed essay that is 3-5 paragraphs.
Answers: This will be different depending on student research.
2. How is evolution occurring today? Please describe at least one example.
Answers: Again answers will vary, some options include evolution of drug resistance, artificial selection
like dog breeding, cichlid fish in African lakes, humans become larger as a species

Summative Assessment
The teacher will assess student knowledge of the standard by grading students Application Questions (see
attachment). An answer key is provided for the Application Questions in the Elaborate section.

Formative Assessment
This lesson plan provides several opportunities for formative assessments:
0.
The teacher can lead a quick class discussion during the Engage section after the students answer
the first question on their data sheets (What is genetic variation?).
1.
2.
3.

The teacher can review data table entries before and during the activity.
Questions can be asked during the activity, such as "What genotype will show a heterozygous
gene? What genotype will show a homozygous recessive gene? What allele combination will give
you incomplete dominance?"
The teacher can lead a class discussion based on the follow-up questions (see attachment). An
answer key is provided in the Explain section.
Feedback to Students
The teacher can provide feedback to students during the initial class discussion about genetic variation,
during the class activity (discussion and data entry can be reviewed), and while students are working on
their follow-up questions.
ACCOMMODATIONS & RECOMMENDATIONS

Accommodations:
1. Download pictures of the different colored snakes to pair with the correct genotypes. During the activity,
students would wear the corresponding pictures according to their genotype. Bw-black snake pw-red snake
3. Have helpers (not part of the class) participating and assisting students in filling out data sheets.
4. White boards or chart paper: students can see how to fill in their data tables.
5. Extended Time

Extensions:
1. Students calculate genotype and phenotype frequencies
2. Enter phenotype frequencies into GeoGebra and find various values.
3. Read and provide written responses to the following articles:


o National Geographic Education: "Camouflage"
o PBS NOVA: "How the Kingsnake Is Still Fooling Predators into Thinking It's Venomous"
o Nature Education: "The Genetic Variation in a Population Is Caused by Multiple Factors"
Suggested Technology: Document Camera, Computers for Students, GeoGebra Free Software
Special Materials Needed:
1.
2.
3.
4.
5.

Bandanas in three different colors:
 8 black bandanas
 8 purple bandanas
 8 white bandanas
One large mobile white board and dry erase markers (or large chart paper)
Computer access
Copies of student data sheets
Graph paper
Further Recommendations:
To make the activity more random, use materials that students can easily hide during "mating."
o
o
poker chips
cubes
o
o
candies
colored paperclips
SOURCE AND ACCESS INFORMATION
Contributed by: Angie Riccio
Name of Author/Source: Angie Riccio
District/Organization of Contributor(s): Lee
License: CPALMS License - no distribution - non commercial
Related Standards
Name
SC.7.L.15.2:
Description
Explore the scientific theory of evolution by recognizing and
explaining ways in which genetic variation and environmental
factors contribute to evolution by natural selection and diversity
of organisms.