Lecture 28: Consumer-resource Interactions I (UNFINISHED))

Question 1

Taxonomic definitions of consumers:

Answer 1

Taxonomic: What is consumed with focus on trophic level

Carnivores: consume animals
Herbivores: consume plants
Omnivores: consume from multiple trophic levels

Question 2

Functional definitions of consumers:

Answer 2

Functional: How it is consumed

True predators
Grazers
Parasite
Parasitoid

Can change depending on life stage.

Question 3

(Functional) True predator

Answer 3

Kill prey immediately, kill multiple prey over lifetime.

Prey and predator can be things other than animals. Ex. seed-eating ants.

Question 4

(Functional) Grazer

Answer 4

Feed on many organisms over their lifetime but rarely lethal in effect.

Ex. leech, bison.

Question 5

(Functional) Parasite

Answer 5

Rarely kill host, consume only one or very few individuals.

Question 6

(Functional) Parasitoid

Answer 6

Eventually kill host, only one host killed in lifetime.

Think of the in-between of predator and parasite.

Question 7

Top-down control
(The World is Green Hypothesis)

Answer 7

Proposes that predators of herbivores prevent herbivores from killing all the plants.

Question 8

Bottom-up control
(The World is Green Hypothesis)

Answer 8

Proposes that the lower plant trophic level controls herbivore populations, which controls predator populations.

Plants are capable of defending against their consumers.
Ex. spikes, thorns, wax covering, poison.

Question 9

How do nutritional obstacles help protect plants from herbivory?
(The World is Green Hypothesis)

Answer 9

Cellulose specifically can be very difficult to break down. The linkage within the molecule is inaccessible, although very nutritious.

Fungi and bacteria tend to be better at breaking down cellulose. This has lead to symbiosis between fungi/bacteria and other organisms so they can make use of the glucose in cellulose.

Plants are also low in sodium. Not necessary for plants, but essential to animals for neurological properties.
Also low nitrogen and proteins.

Question 10

Plant allelochemicals
(The World is Green Hypothesis)

Answer 10

Chemicals toxic or unpleasant to herbivores.

Question 11

Response to plant herbivory: escape in time and space.

Temporal displacement
Morphology
Olfaction
Physical
Chemical
Tolerance

Answer 11

Idrk what was going on with these slides. Need to make slides for each of the terms. All about ways plants avoid herbivory.

Question 12

insect defense against plant defenses
behavioral
response to chem defenses
Sequester plant toxins and use as defense against own pred.