2: Predation

Question 1

Define competition

Answer 1

(-/-) → interaction is detrimental to both species

Question 2

Define predation

Answer 2

(+/-) → Interaction beneficial to one species and detrimental to the other

Question 3

Define mutualism

Answer 3

(+/+) → interaction benefits both species

Question 4

Define commensalism

Answer 4

(+/0) → One species benefits from the interaction, the other is unaffected

Question 5

Describe how a grazer could perhaps be considered a predator

Answer 5

→ from a species interaction perspective
- Many kill targets at a time
- Parts of target is consumed

Question 6

Describe the targets of a true predator

Answer 6

• Kill target
• Generally one target at a time (but many over a lifetime)
• All of target consumed (generally)

Question 7

What are some predator traits?

Answer 7

Mobility
Camouflage
Trickery
Morphology

Question 8

What are some predator behavior strategies?

Answer 8

Sit & wait
Sit & dangle
Sit & pursue
Pursue
Stalk

Question 9

What are some predator domains?

Answer 9

Timing (e.g nocturnal)
Spatial location

Question 10

What are some predator modes?

Answer 10

Individual
Group

Question 11

What are some prey traits?

Answer 11

Mobility
Camo
Aposematism (warning colours)
Mimicry
Trickery
Defensive structures
Autotomy (lizards drop tails)
Chemical defence

Question 12

What are some prey domain shifts?

Answer 12

Timing
Spatial location

Question 13

What are some prey behaviors?

Answer 13

Warning signals
Playing dead
Startling / distraction

Question 14

Describe how prey can be safer in numbers

Answer 14

Dilution effect
Predator confusion
Predator satiation
Improved vigilance

Question 15

What are prey inducible defences

Answer 15

Defence structures that are induced by the presence of predators

Question 16

Describe Daphnia’s inducible defences

Answer 16

Heads become larger
Spines in pulex
Plastic morphogenesis, triggered by external chemical cues
+ 50% survival

Question 17

Describe the study that shows predation can decrease biodiversity

Answer 17

Addicott (1974) → mosquito larvae and protists
Mosquitos had a preference for weaker species

Question 18

Describe the study that shows predators can increase biodiversity?

Answer 18

Paine (1966) → starfish predator removed, mussels number increase unchecked
Keystone species removed = community ceases to exist

Question 19

Describe the study that shows predation can alter rank and relative abundance without affecting biodiversity

Answer 19

Morin (1983) → Newts and tadpoles
Predator preference alters rank of species in community

Question 20

Describe the study that shows that predators can change competitive dominance & context matters

Answer 20

Lubchenco (1978) → periwinkles and macroalgae
Periwinkles feed on dominant competitor = increases biodiversity, to a point