Reebops
The Original Air Puffed Genetic Specimens
Introduction
One of the truly amazing aspects of biology is the tremendous variety of forms of life that exist, all
the way from the bacteria to the blue whale, and everything in between. Even within a single species of an
organism, we find an incredible diversity in the same “kind” of living thing. Consider the example of
human beings. Not only do we see different physical characteristics within the total human population
(such as height, weight, hair color and texture, skin color, facial features, etc), we even see this variation
within the members of a single family. Think of the differences that exist among the siblings of a single
set of parents.
How can we explain the tremendous variation that exists in every species? Why is this variation
important? By studying a set of imaginary organisms called Reebops, you will investigate the sources and
the significance of this variation. Reebops are prolific and require minimal care, making them ideal for
study. Chromosomal analysis has revealed that Reebops have eight pairs, or 16 chromosomes total for all
of their traits.
Objectives
This lab will serve as an introduction to the following concepts:
-
Chromosomes, alleles, genes, gametes, traits, genotypes and phenotypes
-
Changes in genotype and phenotype throughout generations
-
Genetic basis for the variability with the species
-
Punnett Squares & Probability
Materials (per pair of students)
2 sets of chromosomes in an envelope (representing the alleles present in your P1 “parental generation” of Reebops)
4 large marshmallows
2 small nails
3 thumbtacks
2 pipe cleaners
2-4 colored mini marshmallows (number & color based on genetics- green, red, orange, & yellow)
5 toothpicks
1 straw piece
Reebop Lab Procedure:
Part I: Creating the kids (F1 generation) from the parents (P generation)
1. You will be doing this lab with a team of assigned partners.
2. Carefully observe the Parent Reebops. Fill in number 1 of your worksheet.
3. Open the envelope containing the parental chromosomes Fill in number 2 of your worksheet.
4. Turn the chromosomes face down so the letters are NOT visible.
5. Sort the chromosomes by color (orange= female, yellow= male)
6. Sort the chromosomes by length for each parent (longest 2 yellow together, longest 2 orange together, etc)
7. At random, take one chromosome of each length from each of the parental sets, placing them into two
separate piles. You have now made an egg (the orange set) and a sperm (the yellow set). Fill in number 3 & 4
of your worksheet.
8. Put the extra chromosomes back into the envelope.
9. Now combine the two piles, you have now fertilized the egg with the sperm and created a zygote Fill in
number 5 of your worksheet. Each baby Reebop should have a total of 16 chromosomes, 8 pairs, half from
Mom and half from Dad.
10. Gather your materials from the supply area to make your baby Reebop DO NOT EAT Reebops- Toxic!!!
11. Construct your baby Reebop according to your table in number 5 on your worksheet.
12. Replace unused materials to the supply area.
Part II: Creating the Grandkids (F2 generation) from the Kids (F1 generation)
13. In this part of the activity you will pair up with a neighboring team. Try to find a team that has an F1 that is
the opposite sex of yours. If you can’t, one of the teams must change their F1 to the opposite sex. Make sure
you/they change the sex chromosomes accordingly.
14. Using your kid’s chromosomes, turn the chromosomes over so that the letters are not showing and pair them
up as you did in Part I.
15. Select one chromosome of each length (do not be concerned with color) to create the egg or sperm that will be used
in fertilization to create the F2 generation (grandkids of the original Reebops).
16. Now, pair up with your neighboring team for the remaining steps. Fill in number 6 of your worksheet. Be
sure not to physically mix your chromosome sets!
17. “Combine” your pile with your neighbors to create another zygote Fill in number 7 of your worksheet
18.
Using your Reebops decoder sheet Fill in number 8 of your worksheet. (You will not be building this Reebop.)
19. Clean up your lab station. Return any unused items back to the supply area. Points will be
deducted for messy lab areas and misused materials.
Reebop Decoder Key
Phenotype
Genotype
Curly Tail
TT or Tt
Straight Tail
tt
3 body segments
DD or Dd
2 body segments
dd
2 eyes
EE or Ee
1 eye
ee
Blue legs
LL or Ll
Red legs
ll
2 antenna
AA or Aa
1 antenna
aa
3 humps
HH or Hh
2 humps
hh
Red nose
QQ or Qq
Yellow nose
qq
SEX CHROMOSOMES
Female
XX
Male
XY
Reebops Worksheet
1) In this lab you will be randomly choosing the genes of two parental Reebops to create a child. How do you
think the F1 generation will compare to the P1 generation?
2) Parental (P1) Generation: Fill in the Phenotype and Genotype for Mom and Dad Reebop
(You will only be filling this chart out once, as both parents are HETEROZYGOUS for all traits, except sex)
Trait
Phenotype
Genotype
Tail Type
Body Segment Number
Eye Number
Leg Color
Antenna Number
Hump Number
Nose Color
Sex
3)
Female
Male
XX
XY
Explain the processes in Meiosis you are simulating when you perform step 7. (Hint: Segregation and
assortment are involved in the answer.)
_________________________________________________________________________________________
_________________________________________________________________________________________
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4) Draw the gametes you created in step 7.
(Please note that the sperm and egg
ARE NOT drawn to scale!!)
5) Baby Reebop. Using the egg and sperm above describe
your baby Reebop below.
Trait
Tail Type
Body Segment Number
Eye Number
Leg Color
Antenna Number
+
Hump Number
Nose Color
Sex
Phenotype
Genotype
6) Draw the gametes you created in step 16.
above(Please note that the sperm and egg
ARE NOT drawn to scale!!)
7) Grandbaby Reebop. Using the egg and sperm
describe your baby Reebop below.
Trait
Tail Type
Body Segment Number
Eye Number
Leg Color
+
Antenna Number
Hump Number
Nose Color
Sex
8) Draw your Grandbaby Reebop below:
Phenotype
Genotype