Biological Approach

What is the key assumption of the biological approach?

The key assumption of the biological approach is that we can explain behaviour mainly in terms of biological factors.

What are chromosomes made up of?

Chromosomes are made up of DNA.

What is DNA?

DNA is a chain of two or more nucleotides joined together.

What is meant by a gene?

A gene is a segment of DNA that controls the production of one protein.

What is meant by gene alleles?

Gene alleles are different versions of a particular gene.

What are the female sex cells called?

Egg

Write the definition of: Genetic inheritance

Inheritance is when traits are passed down from parent to child.

Genotype

a description of all the genes and alleles in a person’s body

Phenotype

an entrie list of a person’s characteristics

What 2 thing affect phenotype

Genetic and environmental factors

The biological approach studies…

The extent to which behaviour is determined by genes

Genes affect behaviour by altering…

processes in the brain

What name is given to twins who come from one zygote split into two?

Monozygotic

What name is given to twins who come from two different zygotes?

Dizygotic twins

Monozygotic twins are…

Identical and share 100% of their genotype. Have to be same-sex

Dizygotic twins are…

Non-identicial and share 50% of their genotype. Dont have to be the same sex

In twin studies, we assume that...

Monozygotic and dizygotic twins have a similar amount of shared environment.

As Monozygotic and dizygotic twins have a similar amount of shared environment…

Different phenoytpe are a result of different genotypes

Twin study McGuffin et al aim:

How much genetic variation contributes to depression in twins

Twin study McGuffin et al method:

Recruited both monozygotic and dizygotic twins where at least one has depression and then calculated the concordance rate for both types of twins.

Twin study McGuffin et al results :

MZ : 46% concordance rate

DZ : 20% concordance rate

Twin study McGuffin et al Conclusion:

Genetic variation does contribute to depression because the concordance rate for MZ twins was bigger than DZ twins. However envrionment plays a role too.

Evaluation for twin studies

However monozygotic twins are likely to be treated the same due to being identical. Therefore they would share more of their enviornment together which explains why they have a higher concordance rate . Therefore enviornment may play a bigger role than genetics in depression in twins .

Write the definition of: Evolution

Evolution is when a species gradually changes, over many generations.

Write the definition of: A gene mutation

Gene mutations are small changes to alleles which can happen during reproduction.

Write the definition of: Natural selection

is when traits which increase the chance for survival are passed onto future generations.

Strength of biological approach 1

Very scientific - empirical and objective

Strength of biological approach 2

Can be applied to treat mental disorders for genetically inherited conditions

weakness of biological approach 1

Overly reductionist and ignores social and cultural causes of behaviour

weakness of biological approach 2

Biological determinism assumes we have no free will over our behaviour . Decreases responsibility and increses discrimination.