Lesson 7: The Biological Approach (Genetics and Biological Structures)

Question 1

Key assumptions of the biological approach

Answer 1

• Behaviour has evolved through evolutionary adaptation.
• The genes an individual possesses influence their behaviour.
• The biological examination of animals can provide useful information about human behaviour.
• Biological structures and neurochemistry control and influence our reactions to the environment

Question 2

Evolution

Answer 2

According to Charles Darwin, our behaviour has adapted and changed over time through natural selection. This is where profitable behaviours are selected in mates and therefore reproduced. Over time, advantageous behaviours will continue which will continually increase our ability to survive.

Question 3

Heredity

Answer 3

Heredity refers to the idea that characteristics are ‘passed on’ from one generation to the next through our genetics. These characteristics can be physical (e.g. height and hair colour) or psychological (e.g. intelligence and predisposition to mental illness). To examine the extent to which genes influence behaviour, work is often carried out on pairs of twins. These studies often involve comparing the likelihood of a behaviour/disorder occurring in identical twins (who are 100% genetically similar) to the likelihood of the behaviour/disorder occurring among non-identical twins (who are 50% genetically similar). If the MZ twins show a higher concordance rate (shared behaviour) then there is argued to be a genetic component.

Question 4

Concordance rate for MZ twins

Answer 4

It is very rare, however, that the concordance rate for MZ twins is 100%. This suggests that, although there may be a genetic influence, some behaviours could
be a mix of both genetics and environment:

Genotype - refers to the genes an individual possesses i.e. an individual’s genetic make-up.
Phenotype - refers to the observable traits/characteristics shown by an individual that are due to the combined effect of genes and environment.

Question 5

The nervous system is divided into:

Answer 5

The Central Nervous System: This comprises of the brain and spinal cord which act as the centre from which the individual is controlled e.g. through the cognitive processing of the brain.

The Peripheral Nervous System: This comprises of the somatic nervous system and autonomic nervous system. The somatic nervous system comprises the muscles attached to the skeleton and is therefore pivotal for movement. The autonomic nervous system oversees bodily organs and is involved in the fight or flight response.

Question 6

The endocrine system

Answer 6

The endocrine system maintains levels of hormones in the blood that are released by glands. The most important gland is the pituitary gland which is located in the brain. This is sometimes called the master gland because it instructs the other glands in the body to secrete hormones when necessary.