Evolution, natural selection and aggression (3)

Question 1

Define evolution

Answer 1

Evolution is the changes in inherited characteristics in a biological population over successive generations

Question 2

Define Natural selection

Answer 2

Natural selection is the major process that explains how beneficial traits that enhance survival rates of an animal are passed down to the animals next offspring

Question 3

Define sexual selection

Answer 3

An evolutionary explanation or partner preference. Attributes or behaviour that increase reproductive success are passed on

Question 4

How does natural selection create aggression?

Answer 4

Species that are more aggressive will find more land, food and mates which will all increase their survival rate and whether they can produce offspring. T

Question 5

How does sexual selection create aggression?

Answer 5

Females will choose the most aggressive animal as a mate in order to increase their own chance of survival. This means aggressive behaviour will be passed on.

Question 6

Evaluation of natural selection vs aggression: Gender difference

Answer 6

A strength of the link between evolution and aggression is that it explains why males in most species are more aggressive. Females who look for these males will then have higher survival rates if the male is able to protect and hunt for them.

Question 7

Evaluation of natural selection vs aggression: Cultural difference

Answer 7

A weakness of evolutionary theory in explaning aggression is it doesn’t explain how different human cultures differ so much in levels of aggression. For example amongst the Kalahari people aggression is discouraged from childhood while people from Brazil are said to be ‘fierce people’

Question 8

Evaluation of natural selection vs aggression: Application to reproduction

Answer 8

In animals, aggression may be key to survival in order to control food and land and therefore survival. In people it becomes less important however a 1989 study found most males aimed for younger more attractive female partners in order to have the highest chance of fertility.

Question 9

What is Evolution?

Answer 9

The gradual development of different kinds of living organisms from earlier forms during the history of Earth.

This means that due to common ancestors, all species share some genes with each other.

Question 10

How does Evolution happen?

Answer 10

By Natural Selection

• The process whereby organisms that are better adapted to their environment tend to survive and produce more offspring
• Organisms better adapted to the environment are healthier, live longer and reproduce more frequently; passing on the genes that made them reproductively fit onto their offspring

(eg, giraffes with longer necks pass on their genes to the offspring, as they are able to reach more trees and eat more)

Question 11

What are Genes?

Answer 11

• A unit of hereditary information that is transferred from a parent to offspring, and is believed to determine a particular characteristic of the offspring.

Question 12

What is sexual selection?

Answer 12

• A type of natural selection that occurs through preference by one sex for certain characteristics in individuals of the other sex.
• For example the evolutionary psychology stereotype would be that our female ancestors tended to choose tall muscular males who could protect them and their children, leading to those genes being passed on to the next generation

Question 13

What is Mutation?

Answer 13

The changing of the structure of a gene, resulting in a variant (different) form which may be passed on to the subsequent generations

Question 14

What does EEA stand for?

Answer 14

Environment of Evolutionary Adaptiveness

Question 15

What is meant by EEA?

Answer 15

• The environment in which a particular adaptation is said to have evolved
• The conditions that prevailed in the environment at the time a species was adapted in response to

( e.g. The EEA for humans was when humans lived in Hunter-gatherer groups. In the EEA, successful humans were those best suited to the environment in which they lived)

Question 16

How does Evolution Explain Behaviour?

Answer 16

• Evolutionary psychologists look at fossil records to understand the behaviour that would be adaptive. They then compare that to current behaviour in order to argue that behaviour is genetically determined through brain structure and chemistry
• Examples of behaviour that can explained within an evolutionary perspective include: parental investment, mate choice and understanding emotions.
• Unlike our genetic make up, our environment has undergone rapid change; leading to a potential mismatch where we stuck with ‘hardwired’ behaviour that would have served us well thousands of years ago but clashes with the way we live now

Question 17

What is Parental Investment?

Answer 17

• The total energy and resources that parents must expand to produce a particular offspring
• The expenditure increases the survival of the offspring, but also decreases the ability for the parent to invest in other offspring
• The act of having sex can result in much higher parental investment for women, in comparison to males
• For males the minimum parental investment risk by copulation is the cost of sperm; for females the cost is nine months of pregnancy and the risks inherent in childbirth (and potentially more time and energy spent bringing up the children)

Question 18

What is the link between Parental Investment and Mate Choice?

Answer 18

Some argue that these differences in parental investment between males and females lead women to be more selective with their mates than males

Question 19

How does Evolution explain Aggression in Males?

Answer 19

• In the EEA, bigger and stronger males are the most capable of protecting their mates and offspring.
• Also, psychologically aggressive male would be more capable of doing this as they would be more successful at hunting, and defending food resources from other males
• These males also had an advantage in terms of mate choice: Females would prefer a male that could protect her, her offspring, and their food resources due to his aggressive nature.
• Therefore psychologically aggressive males would be more successful in reproducing, as they would be chosen by females as mates due to sexual selection.

Question 20

How does EEA explain Females being Less Aggressive than Males?

Answer 20

• Physical aggression in females with that as an evolutionary disadvantage for their offspring: Females would have spent a lot of the time looking after vulnerable children; and if they engaged and fighting and hurting, this may well have put the lives of the children at risk.
• Therefore, aggressive females would be more likely to have offspring that did not survive to adulthood; and so their genes would not have continued, due to natural selection
• Evolutionary psychologists such Buss (1999) suggested females competed for the best mates through verbal and emotional aggression, by criticising other females and making them seem less attracted to males

Question 21

What are the advantages of using Evolution as an Explanation of aggression?

Answer 21

• Male brains have a small difference in structure in comparison to females, as the result of exposure to testosterone before and after birth. Some argue these differences are linked to male abilities e.g. spatial awareness (hunting/sport), and aggression; supporting the idea that aggressive males were more likely to pass on their genes, due to natural selection in the EEA.
• Mazur (1983) showed fighting between males increases at puberty, when testosterone levels in males increased dramatically; supporting the idea that male hormones (testosterone) are linked with aggression.

Question 22

What are the disadvantages of using Evolution as an Explanation of Aggression?

Answer 22

• There is very limited evidence that evolution explains behaviour, and so we cannot experimentally/scientifically test the idea that aggressive males were more likely to pass on their genes due to natural selection in the EEA.
• Aggressive people are more likely to be injured or die as a result of their behaviour, which challenges the idea that aggressive males can pass on their genes

Question 23

What are the issues and debates of using evolution as an explanation of aggression?

Answer 23

• Reductionism: Some argue it reduces the complex behaviour of aggression to being caused by particular genes that were favoured in the EEA; rather than explaining it more holistically, as caused by the interaction between the range of interconnecting factors (parts of the brain, social influences, cognitive processes, etc)
• Deterministic: some argue that explaining aggression through genes suggests we have little free will; and are programmed to behave aggressively by evolution. This can therefore be used as an excuse to explain aggressively and unacceptability:
  for example some have used this theory to explain rape as an evolutionary strategy that was successful in the EEA so some men might be genetically predisposed to act in this way.

Question 24

What is the Warrior Gene?

Answer 24

The so-called warrior gene comprises particular variations in the X chromosome gene that produces monoamine oxidase A (MAOA), an enzyme that affects the neurotransmitters dopamine, norepinephrine, and serotonin.

Studies have linked the “Warrior Gene” to increased risk-taking and to retaliatory behavior.

Question 25

How are hormones Carried Around?

Answer 25

They are Carried in the Blood, and Operate All Around the Body

They take longer to work than neurotransmitters, and tend to be used to affect longer-term changes