• Bag of large white marshmallows
• Bag of small coloured marshmallows
• Small nails
• Push pins (red and blue)
• Thumb tacks
• Pipe cleaners (cut in half)
• Toothpicks
• Construction paper (2 different colours) – 30 sheets
• Medium sized envelopes - 15
• Ruler
• Scissors
• Pen or marker

Create Rebops (species in question) using marshmallows:

1. Assemble two adult Rebops (see Figure 1).
2. Make the chromosomes seen in Figure 2. Use different colours of construction paper to make the Mom’s chromosomes and the Dad’s chromosomes.
3. Place a full set of Mom and Dad chromosomes in an envelope for each group of students (groups of 2-3 are good). Each envelope should have 28 pieces of paper.
4. Prepare a genotype/phenotype chart (see Figure 3). An overhead transparency works well in a small room or you could use handouts.

Simulate meiosis:

1. Introduce the adult Rebops. Ask the students to comment on their characteristics (i.e., they look identical).
2. Divide students into small groups (2-3 in each group). Hand out the envelopes containing the copies of the adults' chromosomes. Students should then set out the two parental sets of chromosomes with same lengths together and letters facing down.
3. Next, ask the students to take 1 chromosome of each length from each parent and place them together in a new "baby" pile.
4. The baby's characteristics are determined by turning over the chromosomes and decoding them according to Figure 3. You may ask them to to write down the genotype and phenotype.
5. One student from each group can then come and get the materials needed to make their baby Rebop. When completed, all the baby Rebops could go into a designated "nursery" area. Have the students study all the offspring and note any differences.

• You may wish to have a baby Rebop that has extra or missing parts (e.g., legs). You could use this if none of the groups has missorted their chromosomes. This would be a good lead-in to discussing the importance of complete sets of chromosomes.
• If time allows get two groups to pair up and have their new respective Rebops mate. They grow up fast; after all you just witnessed meiosis, fertilization, development and birth in the last 45 minutes or so.

The sorting of the individual chromosomes, followed by taking one chromosome from each parent, represents meiosis. Pairing the new chromosomes to make the baby is fertilization. Development and birth happens when the students make their baby Rebops.

This activity makes use of what are called "genotype" and "phenotype". Genotype is the genetic make-up of a cell or organism, where the phenotype is the physical appearance of that cell or organism due to that genetic make-up.

Rebops can be used with a wide range of age groups. The simple concept of generation could be introduced with younger students. With older students you could quiz them at any stage and ask what is happening, or introduce concepts like linkage and multiple alleles.

Chromosomes are part of the genetic system in every living organism, carrying the DNA and proteins for our cells, whether that organism be bacteria, fungi, plant or animal! Even though the chromosomes can be very different, it is something that connects us. Chromosomes carry the information possible for our cells to function and replicate- they carry information about who we are, including the colour of our hair, how tall we are and how are bodies work.

On the other hand, meiosis is not found in all living livings, but is found in many eukaryotes, including animals and plants. The process allows DNA to be replicated and is especially important for reproduction, like is seen in this activity. This process is how we get bits of chromosome from our mother and father, which get mixed together and taken apart to create a new set of chromosomes that make our set of chromosomes.