Lecture 21

Question 1

eating - herbivores

Answer 1

eat live plant material but don’t kill the entire plant

Question 2

eating - predators

Answer 2

kill and eat entire organisms

Question 3

prey populations influenced by

Answer 3

1. food availability
2. predation
3. non-consumptive effects of predators

Question 4

example of predator/prey dynamics: canada lynx and hare

Answer 4

Booms and busts of snowshoe hare closely predicate booms and busts of lynx - influence population abundance of one another

Question 5

the role of food supply on population

Answer 5

If given enough food, hare populations grow at geometric rates (food shortages and induced plant defenses can happen)

Question 6

the role of predation on population

Answer 6

evidence of functional and numerical responses to hare populations

Question 7

the complementary hypotheses

Answer 7

population affected by both food availability and predation

Question 8

example of complementary hypotheses: hares

Answer 8

Plots: control, fence from predators, food provided, both

Question 9

consumption effects of predation

Answer 9

direct effects through capture and consumption of living prey

Question 10

non-consumptive effects of production

Answer 10

shifts in morphological traits, stress-physiology, and altered behaviour as a consequence of predators being present

Question 11

capture efficiency (b)

Answer 11

the proportion of encounters between predators and prey that results in the predator capturing/eating the prey

Question 12

conversion factor (c)

Answer 12

how many prey are required to produce one predator

Question 13

plant defenses

Answer 13

1. resistance - less likely to be eaten (toxins)

2. tolerance - reduce harm with being eaten (digestion-reducing compounds)

Question 14

toxic plants more common in tropics

Answer 14

more diverse communities of herbivores –> greater variety of defenses needed

Question 15

plant phenotypic plasticity example

Answer 15

As days after infection of tomato plants increase, volatile compounds increase

Question 16

constitutive defenses

Answer 16

produced continuously regardless of what happens to plant

Question 17

induced defenses

Answer 17

concentrations of defensive chemical or morphology increase rapidly in response to herbivore damage (phenotypic plasticity)

Question 18

2 strategies to avoid extinction

Answer 18

1. defense - don’t get eaten

2. refugia - population rescued by immigration

Question 19

defenses

Answer 19

1. camouflage and colouration
2. protection in numbers
3. size

Question 20

aposematic colouration

Answer 20

bright and conspicuous colouration displayed by toxic or distasteful prey

Question 21

protection in numbers

Answer 21

populations so large that the risk of any one individual being eaten is low

Question 22

size

Answer 22

+ too big to be eaten

- requires a lot of energy to maintain

Question 23

refugia

Answer 23

1. spatial

2. metapopulation rescue

Question 24

spatial refugia example

Answer 24

diel vertical migration by zooplankton

Question 25

rescue effect

Answer 25

individuals from larger populations may immigrate and rescue smaller populations