Download Name

Name __________________________________ Date ________ Period _____
REEBOP ALIEN LAB
You are going to construct a baby Reebop in a manner that models human reproduction. A
Reebop is an organic creature, an example of which is depicted below:
Reebops are aliens from the planet Reebo and are a multicellular, sexually reproducing
species. The body cells of a Reebop contain 7 pairs of chromosomes (so 14 total). Each
chromosome has a letter written on it, which represents an allele for a particular trait.
Reebops, just like humans, get one allele from each parent during the process of fertilization.
In this lab, you will simulate the process of meiosis to determine the genes that two Reebop
parents pass on to their offspring. Finally, you will build one of your alien babies.
Purpose: To simulate the process of meiosis and fertilization and to apply the laws of genetics
to the phenotypic expression of Reebop characteristics.
Materials: Large and small marshmallows, pipe cleaners, thumbtacks, push pins, small
pompoms, small pins, large pins, toothpicks, envelope with 7 pairs of chromosomes
from the father and an envelope with 7 pairs of chromosomes from the mother
The table below describes the traits on each of your chromosomes you will show in your Reebop
family:
REEBOP DECODER CHART
Chromosome
#
Description of Trait
1
Body Segments
2
Antennae
3
Dominant Allele and
Phenotype
Recessive Allele and
Phenotype
B – 2 body segments
b – 3 body segments
A – two antennae
a – no antennae
Humps on back
H – two humps
h – one hump
4
Eye color
E – silver eyes
e – white eyes
5
Leg color
L – 2 blue/2 green legs
l – 2 red/2 yellow legs
6
Tail
T – curly tail
t – straight tail
7
Nose color
RR – red
Rr - pink
rr - white
Procedure:
1. With a partner, decide who will be the mother and who will be the father. The mother takes the
envelope labeled “mom’s chromosomes” and the father takes an envelope labeled “father’s
chromosomes”.
2. Each partner puts their chromosomes on the table and matches them by types of letters (each
parent should have one capital and one lowercase of each letter).
3. Fill out Data Table 1: Parent Reebops indicating each parent’s genotype and phenotype based on
the chromosomes that you see on your table in front of you. Note: all but one trait shows simple
dominance, meaning that both homozygous dominant (TT) or heterozygous (Tt) show the dominant
phenotype. Only homozygous recessive (tt) would show the recessive phenotype. The last trait
(nose color) shows a phenomenon of incomplete dominance, where the heterozygous genotype
shows a different color than either homozygous genotypes, so be sure to look at the table closely
for that trait.
4. Both parents should now put the two chromosomes for the first trait back into the envelope and
shake them around. Each parent then reaches in and picks out the first chromosome they find.
Record the letter you have selected in the Data Table 2 under Reebop Baby #1.
5. Repeat this procedure for the remaining 6 pairs of chromosomes.
6. Repeat steps 1-5 for a second Reebop baby, placing information under Reebop Baby #2.
7. Using the Reebop Decoder Chart on the top of this page, determine the phenotypes for each of
your 7 traits for both babies.
8. Use the materials your teacher provides to construct one of your Reebop babies – you should
build one and your partner should build the other.
Name __________________________________ Date ________ Period _____
Data & Observations:
Data Table 1: Parent Reebops – Both parents are heterozygous, so please fill in the chart for
their genotype and phenotype (yes, this is really easy – but the last trait is tricky)
Trait #
1)
2)
3)
4)
5)
6)
7)
Mom Reebop
Genotype
Phenotype
Dad Reebop
Genotype
Phenotype
Body Segments
Antennae
Humps on Back
Eye Color
Leg Color
Tail
Nose Color
Data Table 2: Baby Reebops – Fill in the genotypes and phenotypes for the two babies that
you produce by randomly selecting the chromosomes from the envelopes
Trait #
Reebop Baby #1
Genotype
Phenotype
Reebop Baby #2
Genotype
Phenotype
1) Body Segments
2) Antennae
3) Humps on Back
4) Eye Color
5) Leg Color
6) Tail
7) Nose Color
Sketch of Reebop Baby #
(write which baby you will be building)
Analysis Questions:
1. Your parents had one dominant allele and one recessive allele for each trait. What do we
call this genotypically? ____________________
2. With the exception of the last trait, did these heterozygous parents display the
dominant or recessive phenotype? ___________
Why was this the case? _______________________________________________
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3. What were you simulating when you randomly pulled one of the chromosomes out of the
envelope? _________________________
4. Why do the Reebops get only half of each parents’ chromosomes (think about meiosis)?
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5. Is it possible for two organisms to have different genotypes but the same phenotype?
_____ Explain. _______________________________________________________
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6. Even though all groups in class had identical parents, do all the babies in the classroom
look the same? _______ Why not? ______________________________________
__________________________________________________________________
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7. The Reebop trait of nose color shows something called incomplete dominance. Based on
the genotypes and phenotypes in the Decoder Chart, try to explain how incomplete
dominance is different than complete dominance (what the other 6 traits show).
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