Name:___________________________________Date:_______________Hour:_____BO:_____
Dancing Chromosomes…
…with the spotlight on the processes that
cause genetic variation
Introduction:
Mitosis and meiosis are similar forms of cellular division but the purpose of the divisions
is completely different. Here is a quick breakdown of a few differences between mitosis and
meiosis.
1. Mitosis produces exact copies of the parent cell. Meiosis produces cells that are
different than the parent cell.
2. Mitosis involves one cell division. Meiosis involves two divisions.
3. Mitosis produces 2 diploid (2n) cells. Meiosis produces 4 haploid (1n) cells.
4. Mitosis does not involve crossing over, independent assortment, or recombination.
Meiosis does.
To review the other differences between the two processes consult your Venn Diagram comparing mitosis and
meiosis.
The underlying processes in meiosis lead to genetic variation of sexually reproducing organisms.
In this activity you should be able to describe the processes and how they lead to variation in
offspring.
Your First Task: Make two pair of homologues
Parameters:
1. The chromosomes need to be at least 60 cm long.
2. Label two of the homologues centromere with the number one.
3. Label the other two homologues centromeres with the number two.
4. Create 8 bands of genes that can be easily replaced on each chromatid.
5. One pair of homologues is blue (the color symbolizes where the chromosome
came from, the father)
6. The other pair of homologues is pink. (these came from the mother)
Your Second Task: Simulate Meiosis I with an emphasis on processes that cause genetic
variation.
Now you must begin the exploring dance. This is not a dance that I will be
teaching you but a dance that models the movements in chromosomes that you deduce
from what you have learned about meiosis. (Turn the words in to actions) You will not
necessarily be dancing but it is more of a puppet show. Using what you have created
from your first task (your puppet chromosomes) you need to model the movements,
changes, etcetera… that the DNA go through in meiosis I.
As you figure out your movements make sure everyone is on the same page as far as
what is going on. Everyone should be able to verbalize what each of you is doing. When
you practice verbalizing be sure to focus on the scientific terms such as the phases and
the technical terms used to describe what is going on in each phase.
Name:___________________________________Date:_______________Hour:_____BO:_____
When you are confident with your dance your group needs to come to the front of the
class and go through the dance. As you dance I will be asking you to pause to answer a
few questions here are some examples:
1. In which phase of meiosis does crossing-over occur?
2. Which chromosomes cross-over? Or can any chromosomes cross-over with
each other? Why?
3. How does crossing over result in genetic variation?
4. How is each phase different from mitosis? (similar?)
5. In which phase does independent assortment occur?
6. How does independent assortment result in genetic variation?
7. How does crossing-over and independent assortment result in genetic
variation?
Your Third task: Simulate Meiosis II
Go through the same process as you did in your second task. Listed below are a few
questions that I could ask you as you do your dance.
1. How does meiosis II differ from mitosis?
2. Does meiosis II aid in genetic variation? Yes or no and be able to support your
answer.
3. How do meiosis I and II differ? How are they similar?
Your Final Task: Random Fertilization
Read about random fertilization in chapter 7, section 1. Then explain how random fertilization
leads to genetic variation. Put your answer in a nicely organized complete paragraph.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________