Optimality Models

Question 1

When you don’t know about a phylogeny, what is the best approach in the comparative method?

Answer 1

Averaging individuals into ‘groups’

These groups are groups where your variable is relatively similar among individuals. Eg. a group can be a genus, a subfamily etc.

If you do have a phylogenetic tree, you count individual evolutionary events where there was a change.

Question 2

To do comparitive studies, what do you need?

Answer 2

• A known group with known phylogeny (though, there’s ways to work around this)

Question 3

What are the 3 ‘broad’ steps and two approaches to making an optimality model?

Answer 3

• Balance costs and benefits
• Lay out logic in a transparent way
• Make quantitative and precise predictions and tests

2 approaches:

• For one individual
• Game theory for more than one individual

Question 4

What are the three small steps to doing an optimality model?

Answer 4

1. Define behaviour as a simple decision
2. Define constraints
3. Choose currency

Question 5

At what point on a benefit x cost graph will the optimum point be?

Answer 5

The biggest gap between benefit and cost, with benefit outweighing the cost. (ie. the highest benefit for the lowest cost, but not the absolute highest benefit)

Question 6

What is an evolutionarily stable strategy in game theory?

Answer 6

A strategy (behaviour, or mix of behaviours) that, when adopted by most members of the population, cannot be beaten by any other strategy in the game.

Question 7

What are four pros and one con to optimality models?

Answer 7

Pros

• Explicit
• Testable
• Precise
• General

Cons
- Hard to tell what a mismatch with the model means (ie, it could be due to insensitive test, model needs tweaking or model might be wrong)

Question 8

What are two methods used to test optimality models?

Answer 8

• Find correlation with fitness using surrogate measures and isolation of the trait involved
• Comparative method