Evolution is how inherited characteristics in organism which change from generation to generation. Changes in inherited characteristics lead to differentiation within a species. Natural selection is the process organisms better adapted to their environment, healthier, live longer and pass on their genes.
Evolution is a ‘series of lucky accidents’ because successive mutations gave advantages for the animal that would dominate gene pool. Evolutionary psychologists argue the mind evolves as much as the body & aspects of human behave results from evolutionary adaptions.
Fitness: measure of an animal’s ability to pass on its genes, terms of visible offspring that arise.
Adaption: physical or behaviour said to be adapted to an environment that is tested for suitability to environment. The individuals with the best fit survive & pass on their genes.
Sexual selection: form of natural selection where individuals that are successive in attracting a mate so out-reproduce others in population.
Mutation: a change in genetic structure of an animal or plant that makes it different from others in its kind. E.g giraffes to reach foliage of tree’s higher up, mutations would occur making neck longer, and those successful in getting food would reproduce while smaller neck giraffes would die.
Natural selection & survival of fittest: Refers to how some characteristics may aid survival over other characteristics, those which didn’t and survival would die out as individual wouldn’t survive to reproduce.
Survival of the fittest refers to ‘survival of the fittest genes’ which genes that aid survival are passed on as their parents are living to reproductive age. Genetic mutation may too account for change in genes of species.
Heritable traits: not all characteristics or traits are heritable. Many traits come because of nature & interaction with environment, many genetic tendencies linked with environment. E.g genetic height but final height depends on nutrient.
Group selection: individual would survive more readily if part of a group; help care for offspring & divide up labour within group. Not same as Kin selection as likely not to share genes but staying in a group increases chance of passing on genes.
Kin selection: states animals can save their groups genes by calling out to warn them of danger – even tho risking their own life. Others would survive if had one on ‘watch’ however animals being saved likely to be related to one on watch ensuring some animals (and their genes) survive.
| Strengths | Weaknesses |
| Kettlewell- catched moths & found variations in colour. 27% moths in industrial woods were dark compared to 13% white, contrast to 15% light coloured moths in non-industrial compared to 4.7% that were dark. – Ns as the moths mutated their genes to camouflage better in area to pass genes
Darwin’s scientific methods – reduces behaviour to genetic influences as he found evidence from fossils which matched photos of animals – careful observation to form ideas reducing them to observational features & using it to prove individual genotypes. Application – suggests that behaviour is evolutionary and has developed by mutations which allowed our ancestors to survive long enough to reproduce – if behaviour is part of a survival mechanism allowing us to reproduce than society has implications to accept these behaviours |
Deterministic – fails to consider role of free will of individuals by assuming behaviours are fixed and we have no choice – showing theory is simplistic as humans have choice over behaviour.
Reductionist – behaviour to be a result of dispositional factors ignoring situational factors or the environment – more holistic explanation is needed; evolutionary explanation is over-simplistic of human behaviour Falsification – Darwin looked to confirm his theory rather than falsify e.g looked at fossils & pictures to assure his agenda for changes in species – focused on proof which only confirmed his theory. |