Natural Selection

the idea that organisms pass on traits from one generation to another however these traits are modified/changed especially if they provide a survival advantage

the idea that all living organisms share a common ancestor

a group of organisms that are sufficiently similar genetically to produce offspring through interbreeding

the gradual change in the characteristics of a species over time

the process by which a species evolves to match the demands of its environment

Environment of evolutionary adaptiveness: the environment to which the species have adapted to, gaining traits specific to the environment

a gene that can exist in 2 or more ‘versions’ which give rise to variations in a particular characteristic eg coding for blue or brown eyes

a sequence of DNA that codes for a particular characteristic in an organism

1-animals engage in a struggle for existing and for resources to avoid being eaten and to breed 2-environmental factors create selection pressures which influence organisms to develop new characteristics to ensure survival 3-these characteristics are passed on as the organisms have survival advantages allowing them to breed, transforming to organism into a completely new species and passing down the successful characteristics 4-this causes the advantageous genes to proliferate in society

1-being aggressive would’ve helped to secure resources, provide protection for mates and offspring and increase status and dominance 2-this means that the aggressive species were more likely to be chosen by females therefore more likely to breed and pass on these genes

-the harshness of the hunter gatherer existence would’ve exerted a selection pressure for aggression so individuals with aggressive gene would’ve been better at defending themselves and their family aswell as competing for resources -this gives them an advantage over less aggressive individuals and increased their probability of survival and reproducing causing the aggressive gene to proliferate in the human population due to its survival advantage

when females are more likely to mate with males who show ability to protect, and have high status as these traits are associated with reproductive success

where aggressive males are more successful at competing with rivals and securing mates ie 2 males competing for a female. This means that male species will develop different physical characteristics to females that will help them in this eg large horns/body

humans have specific brain areas dedicated to producing and regulating aggression eg the amygdala which is common in other species too eg monkeys which links to the idea of common descent

genes cause changes to the CNS causing changes in the cognition, emotion and behaviour of species

-aggressive tendencies could be maladaptive in modern society as aggressive behaviour is often seen as socially unacceptable

that aggression exists because it was useful for survival and reproduction

Allen Et Al 2016: found that over history, violence between humans is more common when times are hard eg famines and draughts which supports the view that aggression evolved as a way of securing resources like food and water

1-idea of common descent is supported by brain structures that are linked to aggression and are common in many species eg amygdala which suggests the evolutionary origin of aggression 2-human aggression increases in times of scarcity which supports the evolutionary idea that aggression is triggered under selective pressures where survival is threatened (EMBER and EMBER 1992) 3-aggressive behaviour is found in all cultures which supports the idea that aggression has an innate, evolved basis rather than being learnt 4-explains gender differences such as why males are more aggressive (to get mates and protects/provide)

1-speculative theory: relies on assumptions about the EEA that are hard to prove eg we dont know how our ancestors lived or if the hunter gatherer period existed 2-other alternative theories of evolution: eg sexual selection whereby the traits of a species are influenced by reproduction not survival eg females may select aggressive males due to inc chance of offspring surviving supported by PUTS ET AL 2016 found that more aggressive men had greater mating success, supporting the idea that aggression has been selected for as it provides a reproductive advantage. 3-alternative explanation that aggression is learnt and not innate supported by Banduras SLT and studies. Could be useful in how to reduce aggression 4-reductive theory as it overemphasises genetic and evolutionary influences on behaviour whilst ignoring other influences ie psychosocial influences 5-may be deterministic and stereotypical