Exam 4

Question 1

Decisions about animal habits

Answer 1

Where to live? (habit choice)
how to live and defend that place? (territoriality)
Traveling to another location? (migration)

Question 2

Factors involved in habitat choice

Answer 2

• Abiotic (non-living) factors: heat, water availability, wind, safety from danger, nutrient availability
• Biotic (living) factors: location of mates, food, predators, parasites

Question 3

The ideal free distribution model predicts that:

Answer 3

1. at equilibrium, distribution of individuals matches the distribution of resources (food) across patches
2. at this distribution, individuals receive similar amounts of resources ( food)
   - - this model can be applied to the study of other resources as well

Question 4

Stickleback fish foraging

Answer 4

Milinski asked: Does the Ideal Free model applies to foraging in stickleback fish? Experiment: Tank of 6 fish tested with 2 different feeders (water fleas) set at 2 different ratios 1)  One feeder provided 5 times more food than the other (5:1) 2)  One feeder provided 2 times more food than the other (2:1) *Yes, Prediction 1 supported: fish distributed themselves so that their numbers matched the food probabilities at the feeders (e.g. for test #1, 5 fish at feeder with more food; 1 fish at feeder with less) *Prediction 2 not supported because individual successes unknown

Question 5

Duck Foraging

Answer 5

Harper asked a similar question regarding ducks feeding at a pond Experiment: Two observers threw known amounts of food (bread) from 2 different locations that were 20 m apart; each person represented a separate food patch *Ducks distributed according to food distribution ratio; 1:1 if 2 locations were equal; 2:1 if one location had twice as much food *Ducks did not receive equal amounts of food because some were more aggressive

Question 6

Critical resource: likelihood of disease exposure

2 ways to avoid exposure:

Answer 6

1. avoid habitats with pathogens

2 avoid sick individuals

Question 7

Critical resource: Likelihood od disease exposure

Amphibians like frogs are a good model to study because:

Answer 7

1. they are host to many parasitic infections

2. they can be choosy about oviposition (egg laying) sites