Key words:  forage, herbivore, omnivore, predator, prey, parasite, host, trade-offs, sensory systems
 

1. all animals must find food
1. heterotrophic, respiring organisms
1. different foods:
1. herbivores eat plants
2. omnivores eat plants and animals
3. detrivores eat dead organic matter
4. carnivores eat animals
1. predators kill and consume many small prey
2. parasites eat parts of, but generally do not kill, many hosts
2. all animals face same three problems:
1. find food
2. capture food
3. consume and digest food
4. eliminate wastes
3. different foods require different foraging tactics
1. finding food:
1. sensory systems
2. search tactics: searchers and waiters
3. recognizing food as edible
2. capturing food
1. brute force
2. cunning
3. traps and poison
Study questions

1-5.  Match each organism with its food source
 
 

foraging mode	food type
1. herbivore	A.  flower nectar
2. omnivore	B.  plants and animals
3.  predator	C.  dead organic matter, bodies
4.  detrivore	D.  animals (living)
5.  nectivore	E.  plants (living) or plant parts other than nectar

6. Which organisms would you expect to be more likely to evolve poison for prey capture, searchers or ambush predators, or would you expect poison to evolve equally frequently in both?

7.  Most predators are larger than their prey, however there are exceptions.  Most notably, African wild dogs, army ants and wolves are all smaller individually than their prey items.  What common trait might explain how these diverse organisms capture very large prey?

8.  Herbivores generally don't have to worry about capturing their food:  plants can't run away.  Name three responses plants have evolved to deter herbivory.  Can you name one counter-strategy for each of these defenses?

9.  The interactions among prey and predator, plant and herbivore, is often characterized as an "arms race".  Provide two examples of how prey seek to avoid predators, and a response by a predator to each avoidance strategy.

10.  Predators are often themselves prey of other predators.  Discuss the relative advantages of being an ambush or searching predator from the perspective of becoming prey.

11.  Specialist herbivores and specialist parasites are very common but specialist predators are relatively less common.  Speculate on why this might be true.

12.  Many bog plants have evolved to prey upon insects (i.e., fly traps, pitcher plants).  What might you expect to be the nutritional quality of the soil and water that they are growing in?

Answers