Predator-prey coevolution and dynamics

Question 1

List six different types of inter-specific interaction

Answer 1

1) Competition
2) Mutualism
3) Commensalism
4) Antagonism
5) Neutralism
6) Amensalism

Question 2

Define Competition

Answer 2

An interaction in which both organisms or species are harmed

Question 3

Define Antagonism

Answer 3

An association between organisms in which one benefits at the expense of the other

Question 4

Define mutualism

Answer 4

a relationship between two organisms of different species in which both parties benefit

Question 5

Define commensalism

Answer 5

When one organism benefits from another without affecting it

Question 6

Define amensalism

Answer 6

A relationship between organisms of different species in which one organism is inhibited or destroyed while the other organism remains unaffected

Question 7

Neutralism

Answer 7

A relationship between two organisms that do not affect each other

Question 8

Most predators are limited by what?

Answer 8

Gape limitation

Question 9

How can smaller predators eat prey larger than themselves?

Answer 9

Through pack hunting

Question 10

How can plants defend themselves from herbivores?

Answer 10

They have morphological and chemical defence strategies

Question 11

Most plant material is not consumed directly. Where does it go?

Answer 11

More than 90% enters the detrital pool, giving rise to the ‘brown’ energy pathway

Question 12

What is a parasitoid?

Answer 12

A consumer that lives inside a living resource that gets killed at the point fo hatching of the consumer

Question 13

What is a parasite?

Answer 13

A consumer that eats part of a living resource without necessarily killing it

Question 14

What is prey switching?

Answer 14

When the predator focuses disproportionately on the most abundant species and as that prey becomes increasingly scarce, it switches to the other victim species

Question 15

How does preferential predation on dominant competitors mediate coexistence?

Answer 15

It releases niche space for resident inferior competitors and potential new colonists

Question 16

Who conducted the starfish removal experiment and when? What did this demonstrate?

Answer 16

Paine in 1966. It demonstrated that some species have a disproportionately large effect on its environment relative to its abundance

Question 17

What happened when Paine removed the predatory starfish?

Answer 17

It resulted in a reduction of species from 15 to 8 species (Paine, 1966)

Question 18

Define coevolution

Answer 18

When two separate lineages mutually influence each other’s evolution

Question 19

Give some examples of coevolution

Answer 19

1) Mimicry (too look toxic when you’re not)
2) defenses –> evolutionary arms race between prey and predator
3) Camouflage

Question 20

Give a specific example of coevolution to do with predators and prey

Answer 20

Relative brain size has increased in predators and prey through the Cenozoic

Question 21

What is the Red Queen hypothesis?

Answer 21

A hypothesis that proposes that organisms must constantly adapt, evolve and proliferate to survive while pitted against ever-evolving opposing organisms in a changing environment

Question 22

What are predator-prey oscillations characterised by?

Answer 22

1) Frequency
2) Amplitude
3) Phase shift between prey and predator oscillation

Question 23

If predators are common then prey density ________

Answer 23

Declines

Question 24

If predators are scarce then __________ increases

Answer 24

Prey density increases

Question 25

What is a type 1 functional response?

Answer 25

The number of prey eaten depends only on the prey density, there is no saturation at higher densities

Question 26

Give some real world examples of type 1 functional response

Answer 26

Filter feeders and net building spiders

Question 27

What is the asymptotic type 2 functional response?

Answer 27

Number of prey eaten increases with increasing prey densities and saturates at high prey densities

The percentage of eaten prey decreases with increasing prey density

Common functional response for predators

Question 28

What is the sigmoid type 3 functional response?

Answer 28

Sigmoid shape of functional response is caused by:

• Refuges
• Learning
• Prey switching

Prey refuges protect a subpopulation of prey at low prey densities

At high prey densities, the same maximum feeding rates as in type 2 functional responses can be reached