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Name: ________________________
Teacher’s Name: ________________
Class: ________________________
Date: ________________________
TITLE
How To Use This Lab Skeleton:
The instructions are in ORANGE.
The content is in BLACK. Take out the
orange and type in your responses in
black. You are finished when no
ORANGE remains!
(change this to an original title that sums up the lab)
Introduction:
A trait is a distinguishing feature of an organism. A physical trait can have
multiple different forms, or alleles. If one allele masks the expression of another,
it is said to be dominant. The masked allele is said to be recessive.
In this lab, students will examine multiple human traits that are known to
have only two alleles. One allele will be dominant and the other will be recessive.
Students will make predictions about the prevalence of dominant and recessive
alleles in the class population.
Remember, just because an allele is popular, that doesn’t mean that it is
dominant! For example, blonde hair is recessive to brown hair. However, most
people in Scandinavia have blonde hair. The blonde allele is recessive, but popular,
in this population.
THE BLONDE MAP OF EUROPE
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PURPOSE: The purpose is the reason why the lab is being done. You type the
purpose of the lab (in your own words) here.
HYPOTHESIS: You type your hypothesis here. A hypothesis is a testable
statement about what you think is going to happen when the experiment is
performed. It should include both a guess AND a reason why you think that guess
is correct.
MATERIALS:
You add a list of what you used.
PROCEDURE:
1. Each student should examine their own phenotypic expression for the
following traits and record their data by placing a check mark in the
appropriate box in the “Personal Data” column.
2. Data will be collected for each trait from all of the members of this class.
Record this data in the “Class Data” column.
3. Determine the percentage of students in this class that express each trait.
Record this data in the “Class Data” column.
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DATA: Neatly type your data below. Be sure that EVERY number has a unit and
the correct number of significant figures is used for all calculations.
Trait
Allele
Brown or Black
Hair Color
Anything other
than Brown or
Black
Peak
Widow’s Peak
No Peak
Tongue Rolling
Can roll tongue
Personal Data
Class Data
Class
Percentage
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Cannot roll
tongue
Not Colorblind
Red/Green
Colorblindness
Colorblind
Has freckles
Freckles
No freckles
Free
Earlobes
Attached
Has dimples
Dimples
No dimples
Cleft
Cleft Chin
No cleft
Mid-digital
Hair
Has mid-digital
hair
No mid-digital
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hair
Right-handed
Handedness
Left-handed
Interlocked
Fingers
Left-overright
Right-overleft
Can taste PTC
Tastes PTC
Cannot taste
PTC
For a visual representation, you will always want to graph your data. Pay attention
to where the independent and dependent variables go. You can make a computergenerated graph, or you can print the graph grid below and hand-draw your graph
(use colored pencils to make it look really nice). For this experiment, make a
histogram. Construct a legend so that the reader can interpret the graph.
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Figure 1: Title (look back in your “How To Make A Graph” notes to see how to write a
good title for a graph)
LEGEND
Remember to
label your axes!
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CONCLUSION:
Use your answers to the following Analysis Questions (which you worked out on
your Rough Copy) to construct a conclusion paragraph. YOU SHOULD NOT SHOW
THE QUESTIONS IN YOUR FINAL DRAFT! Your interesting and well-written
paragraph should contain the answers to all of the questions below. Remember to
use scientific writing (passive voice, no personal pronouns).
1. Each trait that is shaded represents the dominant allele. Were the
dominant alleles more popular in the class population, or were the recessive
alleles more popular in the class population?
2. Was your hypothesis supported or rejected? Explain.
3. What is the definition of a dominant allele?
4. What is the definition of a recessive allele?
5. Long Valley, New Jersey was originally named German Valley when it was
settled by in the 18th century by people from Saxony, Germany. What are
some of the traits that the original students of Long Valley would have
displayed if they had done this lab? Would these traits be dominant or
recessive?
6. Using your answer from #5, do you think that the traits of the typical
student from Long Valley have changed since the 18th century?
7. Suggest an improvement or follow-up experiment for this lab (you MUST
make a suggestion!).
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After you have finished writing the Conclusion, go back and write the Title. The
Title should be a short statement that sums up what the entire lab was about. Be
creative – but make sure the title represents the experiment! You cannot use the
title that your instructor used!
Last-minute check! Did you use the spellchecking feature to make sure your words
are spelled correctly? Have you removed ALL of the instructions from the lab
skeleton? Are you going to make sure your lab report prints neatly (do not cut the
data section or the graphs across two sheets of paper!) and is stapled in the upperleft hand corner?