Why are the processes of mitosis and meiosis both important to a living organism?
Mitosis is the process by which existing cells asexually reproduce to create sister cells. Without this process, there would be no way for our bodies to replace damaged, infected, or dead cells. Since cell theory states that all cells are created by other cells mitosis is instrumental in explaining cell theory on a more practical basis. Meiosis is the process of sex cell reproduction. Without this process, another mechanism would have to be in place in order to pass genetic information to the next generation. Mendelian inheritance dictates that genetic information is passed to the next generation through factors or genes. Meiosis is instrumental in this process.
When would an organism need to undergo the process of mitosis? Meiosis?
Mitosis occurs during the normal life of a cell in our bodies. The sister cells that mitosis produces have the same number of chromosomes as the parent cell. Mitosis is an asexual form of cellular reproduction. Meiosis however actually reduces the number of chromosomes in each of the four resulting haploid cells. Also, meiosis is a sexual process meaning that each resulting haploid cell has both paternal and maternal chromosomes. Meiosis is used to create gametes for the purpose of reproduction.
What would happen if meiosis did not occur?
Parthenogenesis (2008) is a process by which organisms can reproduce without male gamete cells. Some lower plant forms, insects, reptiles, and fish utilize this method of reproduction to produce only female offspring. Without the mechanism of meiosis, it is still conceivable that organisms could survive using parthenogenesis.
To answer the question directly, if a eukaryotic multi-cellular organism could not utilize meiosis to produce gamete cells, then reproduction as we know it would cease to exist. Another method utilizing mitosis would have to be evolved through the mechanism of natural selection in order to pass on genetic information to the next generation.
Parthenogenesis. (2008). Retrieved February 13, 2008, from Wikipedia Web site: http://en.wikipedia.org/w/index.php?title=Special:Cite&page=Parthenogenesis&id =190566388