Natural Selection

Question 1

what is descent with modification

Answer 1

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

Question 2

what is common descent

Answer 2

the idea that all living organisms share a common ancestor

Question 3

what is a species

Answer 3

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

Question 4

what is evolution

Answer 4

the gradual change in the characteristics of a species over time

Question 5

what is an adaptation

Answer 5

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

Question 6

what is the EEA

Answer 6

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

Question 7

what is an allele

Answer 7

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

Question 7

what are genes

Answer 7

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

Question 8

explain the process of natural selection

Answer 8

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

Question 9

simplify why aggression may have been passed down

Answer 9

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

Question 10

apply natural selection to aggression

Answer 10

-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

Question 11

what is intersexual selection

Answer 11

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

Question 12

what is intrasexual selection

Answer 12

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

Question 13

what is one reason to accept the evolutionary explanation of aggression

Answer 13

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

Question 14

link evolution to the grounding assumption of biopsych

Answer 14

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

Question 15

why might aggressive traits being passed down be a bad thing

Answer 15

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

Question 16

what does the evolutionary explanation of aggression suggest

Answer 16

that aggression exists because it was useful for survival and reproduction

Question 17

give a study that supports this explanation of aggression

Answer 17

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

Question 18

what are some strengths of this explanation of aggression

Answer 18

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)

Question 19

what are some weakness of this explanation of aggression

Answer 19

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

Question 20

Aggression is adaptive and increases reproductive success. Through natural selection, aggressive traits are passed on, and sexual selection explains why males show higher levels of aggression