Sunday, 14 August 2011

3.1 Differences in Sexual and Asexual Reproduction

Notes


Sexual

-> Identifiable: Distinguish between male/female
-> Meiosis (gamete cell division): 1/2 total number of adult chromosomes in gamete cells
-> Produce 'gamete' cells (male - sperm / female - egg)
-> Fertilisation: gamete cells fuse together (male / female cells fuse together - 23 x 2 = 46)
-> Variation: Populations of individual sexually reproducing species show broad amount of variations

Asexual

-> NOT Identifiable
-> Mitosis / binary fission: 20 chromosome cell -- divides --> 20 x 2 chromosome cells
-> NO Gamete cells produced
-> NO Fertilisation: no gamete cells = no cell fusion = no fertilisation
-> Small variations: identical population (clones)


*Question: What factors affect whether a species will be a sexually or asexually reproducing animal? What are the advantages/disadvantages of each method, that lends itself to particular circumstances (e.g. Scarce populations of species in an area, therefore asexual would be more advantageous)?



No comments:

Post a Comment