Project
In this partner project, Kevin and I created a stop-motion movie of Meiosis out of pictures and an editor. Mr. Wong helped us with the actual picture taking part. I used windows movie maker to create a step-by-step video, and I uploaded it to YouTube.
What is the function of meiosis?
Meiosis is a process that germ cells undergo to create reproductive cells, called gametes. Gametes are haploid cells, which have half the number of chromosomes of normal somatic cells in your body (those are diploid). Because you start out from two gametes, one from each parent, you end up with the normal amount of chromosomes. This combines genes and fulfills the total number of chromosomes that you have. The main reason that meiosis is carried out is to create genetic diversity.
What events promote genetic variation during meiosis?
Crossing over and independent assortment promote genetic variation. Crossing over is the trading of genes between two of the chromosomes. Matching regions on the chromosomes switch from one to another, resulting in two chromosomes that have parts from both of the original chromosomes.
Also, Independent assortment is another way that genetic diversity is developed. Chromosomes during Metaphase I align to the center line, but depending on the order that they are lined up, there can be different genetic combinations.
What causes non-disjunction?
Non-disjunction is when chromosomes do not detach from each other or do not do so correctly. Spindle fiber connection, strength, and operation are all important. If one goes wrong, one daughter cell could end up with 1.5 chromosomes and the other with 0.5. Also, ignored failures to checkpoints cause non-disjunction in cell division.
Panda bears have 42 chromosomes compared to 74 chromosomes found in most bears. How could this occur? Explain in terms of non-disjunction.
Pandas may have been descended from a bear who had an issue with its gametes, one of the gametes being non-disjuncted. It may have ended up with half the number of chromosomes in both of the gamete cells from both the mother and the father. Then, the error caused it to reproduce and that may have started the species of pandas, having 42 chromosomes.
How could this lesson be improved?
This lesson could be improved by making more labs or adding more experiments relating to actual observation. I would like to be able to see separate slides with a microscope that contain different stages of meiosis. We should do an experiment similar to the mitosis cells, but this time, with germ cells and gametes, which are different from somatic cells because they can be diploid and haploid.
mattbiowong 