Saturday, 13 August 2011

3.1 Sexual and Asexual reproduction

Describe the differences between sexual and asexual reproduction.

  • Organisms that shows sexual reproduction show sexes (male/female) whereas organisms that show asexual reproduction has no sexes.
  • Organisms that shows sexual reproduction HAS cells called GAMETES in them - in male organisms these take the form of sperm cells and in the female organisms the egg cells. In plants the sperm cell is often known as the pollen grain and the egg cell is known as the ovule. Organisms that show asexual reproduction has NO GAMETES.
  • The type of cell division that produces gametes is called MEIOSIS. Meiosis has a number of effects one of them is half the chromosomes in the gamete cell. In humans there are 46 chromosomes per cell. However, in gamete cells there are only 23 (this is halved by the process of meiosis). In asexual reproducing organisms there are no meiosis but rather MEITOSIS in eukaryotic cells binary fission in prokaryotic bacterial cells. In this process the number of chromosomes is maintained constantly and are identical.
  • In sexually reproducing population there is a process of fertilization (where the male gamete meets the female gamete) on the other hand, since they have no gamete cells there will be no fertilization happening in asexual reproducing population.
  • If we examine the population of sexual reproductive organisms we will find a broad variation and in asexual productive organisms there will be small variations due to mutation. By enlarge they are identical, this is known as a clone.
Question: [sexual reproduction] Can different organisms with opposite gametes mate? Why or why not? e.g. can you take a gamete from a male donkey and put it with a gamete from a female tiger and produce healthy offspring?

No comments:

Post a Comment