What are the four principles of evolutionary theory proposed by Wallace and Darwin?
- ‘Principle of Variation’: Individuals within a species show variation in their physical and behavioural traits.
• 2. ‘Principle of Inheritance’: Some of this variation is heritable.
• 3. ‘Principle of Adaptation’: Individuals are in competition with one another for scarce resources and some inherited variations will have survival advantages. (neurons can ‘compete’ in the brain)
• 4. ‘Principle of Evolution’: as a consequence of being better adapted to an environment, some individuals will produce more offspring, who will inherit the same advantages. This is called ‘fitness’.
What is adaptive behaviour?
A fine tuning mechanism that produces phenotypic variability. It evolves as natural selection fine-tunes an animal to its environment.
What is proximate causation?
Proximate Causation
–the immediate psychological, physiological, biochemical, and environmental reasons for the existance of a trait
• Sensory systems - need to be able to perceive danger
• Mechanisms that drive muscles that elicit behaviour
• Need to be able to contract muscles to run
• Cellular activities regulate development, nerve function
What is ultime causation?
The reason why a trait increased fitness in the evolutionary past:
• How does the internal machinery work?
• Why does machinery work that way?
• Is that behaviour an adaptation?
• How does that behaviour allow the individual to survive, find food, find mates, escape predators, communicate?
What are spandrels?
Design constraints in evolution that are supportive for adaptions, but not adaptions themselves.
Define evolutionary psychology
The study of the physiological, evolutionary and devleopmental mechanisms of behaviour and experience (ie. the application of Darwinian principles to the understanding of human nature)
What are four categories for biological explanations of behaviour (evolutionary psychology)?
- Physiological (activity of brain/other organs)
- Ontogenetic (Development of structure/behaviour)
- Evolutionary (history of behaviour)
- Functional (why a structure/behaviour evolved)
Understanding a particular behaviour requires explanations from each perspective!
Where was the biggest increase in brain size observed in homo sapiens?
The prefrontal cortex
Criticism of evolutionary psychology led to the development of what two perspectives?
- Evolutionary psychology as just one theory of many
- Bidirectional view: the environment and biological conditions influence EACH OTHER. Individuals create behaviour in the context of culture
How does the length of juvenile period correlate with brain size?
Longer juvenile period (altricial species) have bigger brains and a larger window of plasticity (programming period)
What percent of DNA codes for mRNA?
3%
True or false? DNA is the SAME in all somatic cells of an organism?
True!
True or false? Humans have more proteins than they have genes?
True
Genes collaborate with each other and with non-genetic factors inside and outside the body (bidirectional modality)
How many chromosomes are there in humans?
46 (23 pairs)
Do stem cells divide via mitosis or meiosis?
Mitosis
Meiosis only for sex gametes. Meiosis has processes of recombination which gives rise to increased variation
When do chromosomal abnormalities occur? List a few
When there is an error in cell division following meiosis or mitosis. It can be caused by a missing, extra or irregular portion of chromosomal DNA
- Down syndrome (trisomy 21)
- Kinefelter syndrome
- Fragile X syndrome
- Turner syndrome (X0)
- XYY syndrome
What is the observable and measurable component of a person’s phenotype in regards to behavioural genetics?
Human behavioural and personality ‘characteristics.’ These are detectable expressions of a person’s genotype interacting with his or her environment
What is a genetic marker in linkage studies?
These are segments of DNA that vary among individuals. Patterns of inheritance of genetic markers in large families can be observed.
Using genetic markers is how genes for many diseases were found in classic gene linkage studies.
What is heritability?
The statistical estimate of the proportion of the total variance in some strait that is attributable to genetic differences among individuals within a group.
Expressed as a proportion (eg. .6 or 6/10) so that maximum value is 1.
What are three limitations of heritability estimates?
- An estimate of heritability applies only to a particular group living in a particular environment.
- Heritability estimates do not apply to individuals, only to variations within a group.
- Even highly heritable traits can be modified by the environment.
What are the three ways in which heritability of a behaviour is estimated?
- Examining whether children more closely resemble their adoptive or biological parents
- Comparing monozygotic (identical) and diozygotic (fraternal) twins
- Examining identical twins raised in different households
True or false? The relative contributions of heredity and environment are not additive.
Why or why not?
True
This is because all traits (regardless of heredity) are not rigidly fixed and can be modified by experience.
- Complex behaviours have some genetic loading, that provide an individual with a risk for a particular developmental outcome.
- Our environment is complex and the interaction of heredity and environment is extensive
List the four major experiments that revealed that DNA is the molecular basis of heredity (rather than protein or RNA).
- Griffith’s heat transformation experiment (nucleic acid not protein)
- Avery’s nuclease transformation experiment (DNA not RNA)
- Hershey-Chase bacteriophage experiment (DNA not protein is genetic material)
- Tobacco mosaic virus experiment (RNA is genetic material of some viruses)
List the purines and the pyrimidines
Purines
- Adenine
- Guanine
Pyrimidine
- Cytosine
- Thymine
- Uracil
