Lecture 13 behavior

Question 1

Schooling vs shoaling

Answer 1

Shoaling : Loose social aggregation , movements poorly coordinated
Schooling: highly coordinated movements

Question 2

Benefits of aggregation: hydromechanical advantage (3)

Answer 2

wake turbulance patterns may provide energetic savings to some positions in school
* equivocal evidence (uncertain)
* not advantage for shoaling

Question 3

Benefits of aggregation: increased foraging efficacy (2)

Answer 3

-increased number of foragers can mlocate food source more quickly = advantage if food source is large enough to supply school/shoal
-Goldfish placed with food in a tank both found food quicker when in a group, and spent more total time foraging then hiding from predators (ie more effective use of time due to schooling)

Question 4

Benefits of aggregation: Reduced Predation Risk (4)

Answer 4

Some ways aggregation can reduce predation risk

-detection
* many eyes, noses, etc.

-avoidance
* concentrated prey less likely to be encountered
dilution
* attack on neighbor more likely as group size increases

confusion/evasion
* sudden random or coordinated movements
* difficult for predator to follow single prey item

Question 5

Why do fish have Territory (4)

Answer 5

-shelter from predators
-reduced energetic costs (less time spent searching)
- source of a food supply
-breeding
* attract mates
* build nests

Question 6

Why defend your territory

Answer 6

compare: the value of the defended item vs the cost of defense (energy + risk of predation)