Genes, Environment & Behaviour Flashcards
Genetic Influences on Behaviour Gregor Mendel (1860s)
experiments on biological inheritance:
-How traits and tendencies are transmitted from one generation to the next
Genotype:
- complete genetic makeup of the individual.
- Should be different in everybody…unless you are an identical twin.
- determines how much the environment can influence an organism’s development & behaviour.
Phenotype:
The individual’s observable characteristics (physical) identical twins included…everybody has a unique phenotype.
Phenotype produced via interaction between the genotype & its environment.
identical twins…
- share the same genotype,
- interaction with the environment will mean that their phenotypes differ (Microsoft word- everyone has it but some are different)
chromosomes
double-stranded and tightly coiled molecules of DNA
• Every cell in the human body has 46 chromosomes
• The one exception is sex cell (only have 23 chromosomes, each parent contributes 23 chromosomes)
Genes
the biological units of heredity -> segments of DNA.
Why do we have variations in who we are….
Alleles:
alternative forms of a gene that produce different characteristics
– If the gene received from one parent is dominant, the characteristic that it controls will be displayed ( eye colour -> brown is the dominant gene. Blue is recessive )
– If a gene received from one parent is recessive, the characteristic will only be displayed if the other parent also contributes a recessive gene
Dominant and Recessive Alleles
- So, dominant (brown) + dominant (brown) = DOMINANNT (brown)
- Dominant (brown) + recessive (blue) = DOMINANT (brown)
- Recessive (blue) + recessive (blue) = RESSESIVE (blue)
The Human Genome
The Human Genome Project: a coordinated effort to map the DNA of the human organism
• Began in 1990
• Genetic structure of all chromosome pairs has now been mapped
• Human genome consists of around 20,000 genes
Single genetic factors are unlikely to be the explanation for complex human behaviour.
Behavioural Genetics
2 key concepts
The study of how heredity & environmental factors influence psychological characteristics.
the degree of relatedness and concordance .
degree of relatedness
The extent to which you share genes with ancestral decent. Between 0-1
Concordance ->
display a particular trait & someone else does. (both identical twins have SZ they are concordant. They are discordant if one twin has SZ but the other does not) -> possible to establish a particular trait that might be determined by a certain gene.
family studies
researchers study relatives to determine genetic similarity on a given trait. (Down family tree- does this family have any trace of some disease) .. the closer related the more likely to have similar traits.
adoption studies
adopted people are compared to both their biological and adopted parents. Nature(genetics)/ Nurture(environment).
twin studies
compare trait similarities in identical (MZ ) and fraternal ( DZ ) twins
If something is purely genetic…should be a stronger concordance with MZ
Example: concordance rate for blood type… ( a biological trait) MZ are 100% however for DZ it is 60%….. suggesting it is not purely down to genetics… could be environment?
Should be 100% if purely down to genes.
Ethology
focused on the evolutionary differences between species & are not blank slates
Inherited behavioural adaptations
traits organisms are born with that help promote chances of survival and reproductive success. Evolution programmes us to increase chance of survival
Fixed Action Pattern:
an unlearned behaviour automatically triggered by a particular stimulus… can be alterered and affected by affected by environment but however it is completely innate
2 ways environment shapes behaviour
– Personal adaptation:
– Species adaptation:
– Species adaptation:
- Influence from environment through natural selection. So, over time species have the right equipment so easier to survive.
- Eg human language… originally no one had the ability to speak. Now everyone can communicate… meaning its easier to survive as we can communicate and learn. We also have the ability to solve problems and adapt it is easier to survive.
Personal adaptation:
- Results from our interaction with immediate & past enviroments. Have survived because we have learnt things & we are learning now. ( classical n operant) cannot pass that info genetically so SPECIES ADAPTATION…
- Occurs through the laws of learning
Reaction range
the range of possibilities that a genetic code allows. Genetic code will not determine exactly… it produces a range of possible
three ways in which genotype can influence environment, which can in turn influence personal characteristics
- Influence aspects of parent-produced environment:
- Influence responses evoked from others:
- Influence self-selection of compatible environments:
- Influence aspects of parent-produced environment:
Not only are you a product of your parent genes but your environment is also a part of it. ( if your parents are sporty you may be affected by that eg sporty holidays, skiing. )
