Biological Psychology (Darwin) :Biological Psychology (Darwin) Evolution What is evolution & why are psychologists interested? Reproductive behaviour How do men and women attract/choose sexual partners? How has evolution shaped sexual behaviour (e.g. jealousy, infidelity)? Has evolution affected how men & women approach child-rearing?


Evolution :Evolution Charles Darwin’s attempt to explain the huge variety of living things… …in a scientific way …without drawing upon religious ideas Evolution is not about progress (e.g. being the biggest, fastest or strongest). It is about adaptation.


Slide 3:Individual do not evolve, species evolve. This happens through the process of natural selection. The members of a species that are best suited / adapted to a particular environment will survive and pass on their genes. The rest may die (or fail to pass on their genes). Consequently, future generations will be better adapted to the environment (i.e. the species has evolved / changed). Evolution and Adaptation


Evolution :Evolution Each living thing (organism) has a set of characteristics encoded by its genes The organism inherits its genes from its parent(s) Variations between organisms are caused by variations in the genotype


Evolution :Evolution


Evolution :Evolution An organism’s ability to survive depends on how well its characteristics allow it to: Exploit the opportunities available in its environment Avoid or deal with the threats presented by its environment We call this the organism’s fitness


Fitness :Fitness


Fitness :Fitness Yummy!


Evolution :Evolution Fit organisms are more likely to survive into adulthood than unfit ones. Consequently, they are more likely to mate and have offspring They pass on their genes to the next generation Gradually, the genes for successful characteristics spread through the population


Evolution :Evolution Fitness is all about how well an organism is adapted to its environment The environment changes over time – sometimes gradually, sometimes rapidly So a characteristic/gene that is adaptive at one time may become maladaptive if the environment changes


Fitness :Fitness


Evolution :Evolution Genotypes change due to: Random mutation of DNA Recombination of genes due to mating New species emerge as adaptive changes spread through a population Species compete with each other – the fittest ‘wins’ by reproducing more effectively Species go extinct when their environment disappears or they are out-competed


Evolution Myths :Evolution Myths Characteristics acquired during the lifespan can be passed on to offspring Humans are descended from monkeys Other animals are ‘less evolved’ than us Humans are the ‘end product’ of evolution


Evolution & Psychology :Evolution & Psychology Evolutionary psychology regards humans as subject to same evolutionary processes as other animals (continuity) Assumes that behavioural characteristics can be inherited just like physical ones Tries to explain human behaviour/psychology in terms of evolutionary processes


Evolution & Psychology :Evolution & Psychology Slow Physically weak Lacking agility Poor climber Small teeth No claws Highly dependent young Poor night vision Large brain Planning Imagination Language Social organisation Tool use Communication Problem solving