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Sexual Selection and Dimorphism. Characteristics evolve because they have been passed from one generation to the next via the genes This requires the organism: To live to reproductive age To mate successfully To ensure the offspring’s survival. www.psychlotron.org.uk.
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Sexual Selection and Dimorphism • Characteristics evolve because they have been passed from one generation to the next via the genes • This requires the organism: • To live to reproductive age • To mate successfully • To ensure the offspring’s survival www.psychlotron.org.uk
Natural & Sexual Selection • Natural selection • Ability to survive in a particular environment (fitness) • Sexual selection • Ability to attract/find a mate and reproduce successfully • These are separate processes – the characteristics that facilitate reproduction do not necessarily increase survival chances www.psychlotron.org.uk
Male Female Sexual Dimorphism www.psychlotron.org.uk
Male Female Sexual Dimorphism www.psychlotron.org.uk
Male Female Sexual Dimorphism www.psychlotron.org.uk
Sexual Dimorphism www.psychlotron.org.uk
Sexual Dimorphism • In many species, males have characteristics (e.g. brighter colouration, exaggerated tails) that serve to attract females • Suggests that males are competing for the attention of females • Suggests that, in many species, females do the choosing www.psychlotron.org.uk