Principles Flashcards
What is the fundamental force driving life on earth
Evolution
What 2 main characteristics has evolution placed in all individuals
All individuals are genetically selfish and optimally efficient
What is behavioural ecology
A discipline that aims to explain to explain the survival and reproductive value (i.e. the evolutionary significance) of behavioural traits
What are the two fundamental themes of behavioural ecology
Natural (and sexual) selection maximises gene survival, and individuals (=vehicles for genes) should behave to maximise individual and inclusive fitness
The optimal behaviour needed to maximise fitness will be efficient and depend on the behaviour of others, and on the environment
What are the 3 fundamentals required for behaviour to work
Sense organ
Neuronal/ hormonal system
muscle
What does a sense organ do
Gathers information about the physical, chemical and biological environment
What are the basic principles of the nervous system
Action potential (Electrochemical flux) passes down a neuron from dendrites/sense organ and generates the release of neurotransmitter into the next neuron/ neuromuscular junction Concentrated ganglia/brains allow information storage
Give an example of how hormone levels can effect behaviours
Davidson et al (1968) found that female rats were very aggressive to males when they had low levels of oestrogen but would go into lordosis when they had a high does
Describe a muscle
Motors that allow physical movement (and behaviour)
What are the differences between simple behaviour such as reflexes and more complex behaviour such as fixed action patterns
Reflexes have a simple stimulus and neural pathway and the form it occurs in is constant, consistent and usually momentary
A fixed action pathway is and innate and stereotypical behaviour with a more complicated neural control and stimuli. It is also more prone to vary in relationto context and habituation
example of a fixed action pattern
the moth escape response
What are proximate explanations
descriptions & explanations based on immediate cause and mechanism (stimuli, genetics, hormones, experience)
What are ultimate explanations
explanations based on survival/reproductive value or function
What is evolutionary fitness
It is a kind of measure of currency on how good the behaviour/trait is for allowing for individual survival and reproductive success
how is reproductive fitness quantified
Between 0 and 1 where 0 means the behaviour or trait contriubutes nothing to survival and reproduction and 1 means its 100% contributing to survival
What can prevent optimality from being reached
Mutation
Linkage (beneficial genes linked to deleterious genes)
Pleiotropy (single genes with multiple effects)
Phylogenetic inertia / evolutionary lag
Environmental variation
Trade-offs
Competition and conflict!!
What are the 5 steps of behavioural evolution
Behavioural variation in a population
That variation is heritable
Individuals compete to survive and reproduce
Survival/reproductive success is influenced by behaviour
Behaviour with high fitness is selected
What are the 3 assumptions needed to support behavioural evolution
Behaviour is genetically controlled and heritable
Timespans of selection are sufficient for adaptation to happen
The unit of selection is the INDIVIDUAL and ITS GENES (not the GROUP or the SPECIES)….
What is heritability
Proportion of phenotypic variance attributed to genotypic variance
Varies from 0 (= completely environmentally determined) to 1 (completely genetically determined)
What conditions re requires for non-kin altruism to occur
Altruistic act has relatively low cost (high cost encourages cheating and defection)
Benefit exceeds the cost
Defection leads to ‘punishment’ (e.g. via losing cooperating benefits – even across the group)
- Encounter rate probabilities between individuals are high (=spatial clustering)
- Individuals recognise one-another (= ‘higher’ animals)
What is an ESS
An ESS is a theoretically determined strategy which, if adopted by the majority of the population, cannot be beaten (or invaded) by an alternative strategy
Why is non cooperation an ESS
Because it cannont be invaded by an alternative strategy
Example of non kin altruism
Vampire bats sharing blood meals
What is optimality theory
Theory that seeks to describe how traits are optimal, i.e. they generate the most profitable ratio of fitness benefits to fitness costs
What is optimal behaviour
It is a behavioural strategy that maximises fitness
What does the IFD predict
that the distribution of animals among patches will minimize resource competition and maximize fitness
What does the ideal mean in IFD
It’s ideal, because animals have complete information about the availability of resources
What does the free mean in IFD
It’s free, because animals are free to go where they will do best
Example of IFD
Whitham found that stem mother aphids exhibited IFD when they form galls in narrowleaf cottonwood. He found more galls on larger leaves than on small and that the aphids which shared leaves had the same average reproductive success as those that were alone, thus being a ideal free model
In 4 words, described the hypothetico-deductive method
Observe
Hypothesize
Predict
Test
What are the characteristics of good hypotheses
Consistent with observations
Consistent with logic
Consistent with knowledge
TESTABLE
What 3 things should tests do
be explicit (but can support or reject a number of hypotheses)
eliminate / reduce confounding effects
should be explicit to answering the prediction
What 4 forms can tests take
observational, experimental, comparative or theoretical
What should be considered when trying to make good observations
Observations shouldbe made within an established framework (derived from previous hypothetico-deductive approaches) ie using experience and knowledge
What is the caveat between closely related species and comparative tests
Closely-related species will show similarities because of common descent – not necessarily because of comparative adaptations
What are the strengths of experimental tests
more rigorous
avoids confounding variables
What are the limitations of experimental tests
May be artificial
good controls are hard to achieve
What is a strength of observational tests
More natural
What is a limitation of observational tests
confounding variables
What is the strength of comparative tests
Includes broad evolutionary patterns
What is the limitation of comparative tests
Phylogenies are not always available
What do statistical tests measure
either differences or similarities between data sets
Why is it important to have a big sample size
the more power the test has to be confident that chance does not explain the result
What is the equation for confidence
confidence = signal/noise * square root of sample size
What is a confound
a factor that drives similarity / difference in another factor
When designing studies what are 4 things to beware of
Psuedoreplication
Auto-correlations
Excessive multiple comparisons
Unreasonable post hoc testing
