3. Competing for Resources Flashcards
When does competition arise?
Whenever two or more individuals compete for the same resource
What are the two ends of the competition spectrum?
Scramble and Contest
When would scramble competition occur?
When resources are divisible or indefensible
No ownership
Expected payoff = Value / Number of competitors
When would contest competition occur?
When resources are indivisible or defensible
Contestants fight for control
What is ‘Game Theory’?
The branch of mathematics which solves for ‘best’ behaviour when an individual’s payoff depends on the behaviour of others
What is the ideal free distribution?
When no individual can gain by switching environments
When should a predator switch from a rich resource area to a low resource area?
When the number of competitors in the rich area reaches a certain threshold
What is the Evolutionarily Stable Strategy?
A strategy which, when common in a population, cannot be invaded by any other mutant strategy (no other strategy can do better)
What is the IFD a result of?
an ESS strategy - go to the patch which at the moment yields the most profit
When would the IFD not be achieved?
When animals can defend against intruders
When should animals defend territories?
When the benefits of competition avoidance outweigh the costs (energetic, injury risk etc)
When might it be beneficial to share a territory instead of defend?
When the fitness payoffs outweigh those of defending
The addition of one other individual may decrease energetic costs of defence greater than they detract from the cost of less resources
Why might there be individual variation in behaviour?
Random noise (developmental fluctuations) Condition dependent strategies (best of a bad job) Frequency dependent selection (ie stable polymorphisms - sneaker males vs large males)
