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Adaptation and Behavior
Lesson #1: Introduction to Inheritance - Inherited Human Traits
Time Frame: 1-2 hours
Learning Standards:
Science
Life Science: Plant (and Animal) Structures and Functions;
1) Differentiate between observed characteristics of plants and animals that are fully
inherited (e.g., color of flower, shape of leaves, color of eyes, number of
appendages) and characteristics that are affected by the climate or environment
(e.g., browning of leaves due to too much sun, language spoken).
Skills of Inquiry
1) Ask questions and make predictions that can be tested.
2) Select and use appropriate tools and technology in order to extend observations.
3) Keep accurate records while conducting simple investigations or experiments.
4) Recognize simple patterns in data and use data to create a reasonable explanation
for the results of an investigation of experiment.
5) Record data and communicate findings to others using graphs, charts, maps,
models, and oral and written reports.
Math
Data Analysis, Statistics, and Probability
1) 5.D.2 Construct and interpret line plots, line graphs, and bar graphs. Interpret
and label circle graphs.
Number Sense and Operations
1) 6.N.9 Select and use appropriate operations to solve problems involving addition,
subtraction, multiplication, division, and positive integer exponents with whole
numbers, and with positive fractions, mixed numbers, decimals, and percents.
Student will be able to:
1) Collect, analyze, graph, and interpret data about inherited traits found in the
classroom population.
2) Understand that human traits are inherited and variable.
Resources and Materials:
Item
Science Journals
Examples of human inherited traits
Pictures of the different types of human traits
Inherited traits of humans teacher chart (overhead or copy on
the board)
Inherited Human Traits student handouts (student chart, data
and analysis questions, and graph outline)
Chart showing Frequency of Traits in the General Population
Calculators
Amount
1 (in binder)
25 (in bin)
1 (in binder)
25 (in bin)
1 (in binder)
25 (from classroom)
General Teacher Background Information:
Gregor Mendel, an Augustinian monk with farming experience and mathematical and
scientific knowledge, is known as the father of modern genetics. Mendel was intrigued
by his observations in plant hybridization. He felt there might be some mathematical
relationship among the traits observed in different generations of hybrid plants. Mendel
posited that inheritance is based on pairs of particular factors and these factors occur in
pairs in each parent. These factors later became known as genes. He also concluded
that a pair of factors are segregated or separated during the formation of sex cells so
that each cell receives only one of the pair from each parent (Law of Segregation). He
also felt that since paired elements are capable of separating, then reappearing in their
original form, and then pairing differently in a later union; they are not altered as passed
from individual to individual.
Mendel also identified a dominant form (allele) for each gene and a recessive
form (allele) for each gene. In humans, earlobes can be detached (dominant trait) or
attached (recessive trait). In general, inheritance ends up being much more
complicated. For example, some traits are controlled by many genes and some genes
have many different alleles. Also, alleles do not always have a strict
dominant/recessive relationship. Human characteristics such as eye color and skin
color have complex modes of inheritance.
Focus Activity: Ask students to individually write down 10 traits (characteristics) about
themselves in their science notebooks. Then move into the introduction activities.
Introduction: Ask students to work in small groups to separate these traits into 2
groups – traits that they inherited from their parents and traits affected by the
environment. Give an example of each type of trait first. For example, eye color is an
inherited trait and language spoken is affected by the environment. Some groups may
also have a third list; traits that are BOTH inherited and affected by the environment. As
a class, make a list of inherited human traits on the board (You may use the list
provided to get additional ideas). Discuss the following questions as a class. How do
you know these traits are inherited? Could any of these traits also be affected by the
environment?
Activity:
1) Give each student a chart to record their data about human traits. Working
individually, students will complete an inventory of their traits and then compare
their traits to a partner’s traits (2-3 students in a group). Students may use the
pictures provided to help determine what the different traits look like.
2) After the group discussions, ask students to make predictions about which type
of trait will be most common in the classroom population. Students will record
their predictions on their chart.
3) Students will share their results with the class and the teacher will tabulate the
classroom number (using the overhead of the chart provided). Students will add
the classroom data to their chart. Instructor will lead a brief discussion of the
classroom data.
4) Then, students will determine the frequency of each trait (percentage) using the
formula provided and record the frequency in their chart. Allow students to use
calculators to determine the correct frequencies. They should check their work
with their group. If percentages are not cover in students’ math curriculum,
record the frequencies as counts rather than percentages.
5) Students will make a bar graph (using the graph outline provided) representing
these frequencies. Remind students to label the Y-axis of their graph. Use
either the percentages or counts graph as appropriate.
6) Students will compare their results to their initial predictions and answer the data
analysis questions. Provide students with the chart showing the Frequency of
Traits in the General Population.
Closure: Discuss the following questions as a class. Is there a pattern in the traits
present in our classroom population? Why are there so many similarities or differences
in our classroom population? Did you inherit any of these traits from your parents? Did
you inherit any of these traits from your grandparents? Why would a scientist care
whether populations were similar or different? Are humans all the same or all different?
What are the benefits of having differences among humans? What might happen if
every human was identical?
Note: You may choose to discuss how traits are inherited and passed on from parents
to their children (genes) or wait until the next lesson.
Assessment: List of human traits in the science notebooks, completed inherited human
traits chart, graph, and analysis questions, participation in class discussions
Examples of Human Inherited Traits
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Gender (male or female)
Right handed / left handed
Cross left thumb over right / cross right thumb over left
Number of limbs, fingers, toes
Hair color (natural)
Hair texture (natural)
Eye color (natural)
Height
Presence of freckles
Presence of dimples
Thumb flexibility (straight or curved)
Cleft or smooth chin
Attached or unattached earlobes
Pointy or straight hair line
Ability to roll tongue
Allergies
Length of fingers
Circumference of wrists
Length of feet
Inherited Traits of Humans
Total Population (# of students in the class): ________
Character
Number Observed in the
class:
Percentage of Population
with Trait
Gender
Male
Female
Male
Female
#_____
#_____
_____%
_____%
Detached
Attached
#_____
#_____
_____%
Can roll
Can’t roll
Can roll
#_____
#_____
_____%
Earlobes
Tongue
Chin
Attached
Cleft
#_____
Hairline
Thumb
Pointy
Flat
#_____
Straight
Cleft
Detached
_____%
Can’t roll
_____%
Flat
_____%
_____%
Pointy
Straight
#_____
#_____
_____%
_____%
Curved
Straight
Curved
Straight
#_____
#_____
_____%
_____%
Data Interpretation (Using Percentages)
1) Calculate the frequency (percentage of the population with the trait) for each trait.
Use the following formula:
Number observed x 100 = Percentage (%)
Total Population
Use a calculator to determine the frequency for each trait on your table. You
may work with your partner. Check your frequencies by adding the percentages
for each trait. The added percentages should equal 100.
2) Create a bar graph (using the percentages graph outline provided) to show the
different frequencies for each human inherited trait.
Data Interpretation (Using Counts)
1) Create a bar graph (using the frequency graph outline provided) to show the
different counts for each human inherited trait.
Analysis Questions
1) Compare your predictions with the class results. Were most of your predictions
correct or incorrect? Why?
2) Compare your results to the known frequencies for the general population (chart
provided). Are your classroom percentages similar or different? Explain what
you observe.
3) Where did these traits come from? Did you inherit any traits from your parents?
Did you inherit any traits from your grandparents? List those traits. Do you think
you will pass on any of these traits to your children? Explain.
4) Are humans all the same or all different? What are the benefits of having
differences among humans? What might happen if every human was identical?
Frequency of Traits in the General Population
(percentages are approximate)
Trait
Gender
Frequency of
Form 1
Male – about 50%
Earlobes
Attached – 25%
Frequency of
Form 2
Female – about
50%
Detached – 75%
Tongue
Can roll – 70%
Can’t roll – 30%
Chin
Flat – less frequent
Hairline
Cleft – more
frequent
Pointy – 75%
Thumb
Curved – 25%
Straight – 75%
Straight – 25%