Information on Gametogenesis, reproductive organs and the sexual cycle, fertilization, cleavage and formation of the blastula, gastrulation and the establishing of germ layers.© BrainMass Inc. brainmass.com July 20, 2018, 10:05 am ad1c9bdddf
Gametogenesis: This is the production of haploid (n=1) gametes (eggs and sperm) for the purpose of sexual reproduction. Why have sex? Simply put it allows for a mixing of genetic material. Therefore the organisms that reproduce sexually must halve their genetic component through meiosis (DNA replication, segregation of homologous chromosomes, first cell division, segregation of duplicated chromosomes, second cell division). During the production of sperm all 4 cells produced by meiosis form mature sperm where as in the case of oogenesis only one ova and three polar bodies are formed.
Reproductive organs: The information you will need to know for this section will greatly depend on the organisms you have covered. You should make a list of the organisms you have talked about in this section and draw out the reproductive organs (male and female) for each. For a general review of spermatogenesis in humans see http://academic.pgcc.edu/~aimholtz/AandP/206_ONLINE/Repro/Images/spermatogenesis.jpg The generations of ova is slighly more complex in vertebrates. All the eggs a female will carry are produced during embryogenesis. They are halted in meiosis I until sexual maturity is reached. At puberty hormonal changes during menstruation reactivate the cell cycle proceeding to metaphase II and arresting again until fertilization. See http://science.tjc.edu/images/reproduction/oogenesis.jpg for a good illustration on the matter. Sexual cyle information will also depend on the ...
Review of embryology terms such as gametogenesis, reproductive organs and the sexual cycle, fertilization, cleavage and formation of the blastula, gastrulation and the establishing of germ layers.