Lecture 2 Flashcards
Migratory behaviour
Has a strong genetic (innate) component
How to test adaptation in an ideal world
Experimental evolution:
Compare ancestral traits with those of individuals that survived and reproduced
Reauires measuring a trait over multiple generations
Difficult to do outside of a petri dish
The reality of testing adaptation
Behavioural ecology:
- Observation and experiment: identifying present function can help to build confidence that it helped in their evolution - is the function adaptive?
- Comparative method: comparing to see if the same behaviour is present in different species exposed to the same environments - evidence of the adaptive value of that trait
Problems with the comparative method of testing adaptation?
- Shared ancestry/ecology: traits are not statistically independent, and correlations are inherited from a common ancestor/similar ecology, not function. Solution is to control for phylogeny
- It’s still only a correlation: can’t do experiments . Solution is replication across lineages
Cephalisation index
Measure of the size of the brain relative to size of the body
Brain size and behaviour
- Across vertebrates, there is a tendency for pair-bonded species to have a larger brain than other systems
- Migrant bird species have a lower residual brain size than resident bird species
- Species with larger brains can open puzzle boxes more successfully to access food
Brain size and development
Brain size correlated with how long a bird stays in the next with its parents
Iwaniuk & Nelson, 2003
Why do migratory birds have smaller residual brain size compared to resident bird species?
Resident bird species must cope with more extreme environmental change as they must live through all seasons
Sol et al. 2010
HV size and innovatory behaviour
Relative size of the hyperstriatum ventral predicts feeding innovation rates in birds
Timmermans et al., 2000
What makes a behaviour plastic?
If it responds to environmental change
