Selection & Genetic Drift

(c) Selection. Natural selection is the non-random increase in frequency of DNA sequences that increase survival. Sexual selection is the non-random increase in frequency of DNA sequences that increase reproduction. The differences in outcome as a result of stabilising, directional and disruptive selection.
(d) Genetic drift. The random increase and decrease in frequency of sequences, particularly in small populations, as a result of neutral mutations and founder effects.
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Selection in Peppered Moths

peppered moth gameClick the icon to access an interactive presentation about Dr Kettlewell’s experiments on natural selection in the peppered moth.

 

Sexual Selection

This webpage offers a concise and clear explanation of the significance of female choice in sexual selection.

http://evolution.berkeley.edu/evosite/evo101/IIIE3Sexualselection.shtml

The subsequent article may answer some questions regarding the evolution of apparently disadvantageous traits and the mechanisms by which they can evolve a role in sexual selection. http://evolution.berkeley.edu/evosite/evo101/IIIE3aRunawayselec.shtml

This video discusses the role of sexual selection in the evolution of species.

Watch Richard Dawkins on Sexual Selection in Educational & How-To  |  View More Free Videos Online at Veoh.com

 Stabilizing, Disruptive & Directional Selection.

The slides on the following link explain these three types of selection.  http://www.execulink.com/~ekimmel/natural_selection.htm

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