Lecture 6: Ultimate Consequences 1 Flashcards Preview

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Define the 'life history strategy' of a species.

Overall pattern in average timing and nature of life history events determined by allocation of time and energy between growth, reproduction, and survival.


What are the assumptions of life histories?

● There is some measure of fitness that is maximised.
● Constraints and trade-offs limit the set of possible
● There is sufficient genetic variation to permit the
attainment of the optimal combination.


Define 'trade offs'.

The linkage between traits that
constrain the simultaneous evolution of two or
more traits.


What are the main trade offs?

● Current reproduction vs survival
● Current reproduction vs future reproduction
● Growth versus reproduction.


What are the different types of trade offs?

● Physiological trade-offs
● Microevolutionary trade-offs
● Macroevolutionary trade-offs.


Define 'physiological trade offs'.

Allocation decisions between two or more
processes that compete directly for limited


Define 'microevolutionary trade offs'.

● Defined by the response of population to selection
● Existence of genetic correlation between the traits
● This include most physiological trade-offs.


Define 'macroevolutionary trade offs'.

Comparative analysis of variation in traits among
independent phylogenetic events.


How can you measure trade offs?

– Phenotypic correlations
– Experimental manipulations
– Genetic correlations from related individuals
– Correlations across phylogenetically related species.


Why are trade offs not found?

– Phylogenetic fixation
– Income vs capital breeders
– Variation in acquisition and allocation of energy
– Genotype by environment interactions.


What is 'Lack's hypothesis'?

The natural selection will favour the clutch size which produced most surviving offspring.