Lecture 20: Predator-prey interactions. Flashcards

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1
Q

What are some examples of Exploitation interactions?

A

Predation
Parasitism
Herbivore

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2
Q

What do Herbivores eat?

A

They eat live plant matter, but do not kill the plant that they eat from

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3
Q

What do predators eat?

A

They eat, and kill the animal that they eat.

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4
Q

What are three main factors that influence prey populations?

A
  • Food availability
  • Predation
  • non-consumptive effect of predators
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5
Q

What is the best example of predator - prey population dynamics?

A

The lynx and the Hare.

Their populations are highly dependent on the other

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6
Q

How do Hare populations affect Lynx populations.

A

When hare populations are high, Lynx populations are high.

When hare populations are low, hare populations are low.

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7
Q

What are the Consumption effects of predation?

A

direct effects
of predators on prey populations through the
capture and consumption of living prey

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8
Q

What are the Non-consumptive effects of predation?

A

changes
to prey that results as a consequence of
predators being present, including shifts in
morphological traits, stress-physiology, and
altered behavior

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9
Q

True or false:

Predators need to kill prey in order to impact the prey population

A

False,

When predators are simply within the environment there can me measurable affects on the prey species

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10
Q

When modeling predator - prey interactions, what is (H) and what is (P)?

A
H = Prey 
P = predator
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11
Q

When looking at the basic Exponential growth of the prey, what do teh following represent? (Slide 16)

Nh -
t -
rh -

A

Nh - prey population size

t - time

rh - prey pre-captia rate of increase.

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12
Q

True or false:

The Lotka-Volterra model for predation ignores intra-specific competition, assuming that predation will control population size, not competition.

A

This is true.

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13
Q

When attempting to model predation, what will (b) and (Np) represent

A

b = capture efficiency of the prey by the predators

Np = Predator population size.

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14
Q

What is Capture Efficiency (b)

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

(the success rate of the predator)

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15
Q

If a predator catches 1 out of every 50 prey, what would be their (b) value?

A

0.02

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16
Q

When you include the growth of predator populations within the predation model,
what would
(c) and (dp) represent?

A

c = conversion factor of prey and predators

dp = per capita death rate of predators

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17
Q

When you include the growth of predator populations within the predation model,
what would
(c) and (dp) represent?

A

c = conversion factor of prey and predators

dp = per capita death rate of predators

18
Q

What is the Conversion Factor?

A
Essentially how many
prey are required to
“produce” one
predator
How many prey
individuals a female
needs to consume to
make one offspring
19
Q
A predator needs to
eat 5 prey individuals
to have enough excess
energy to produce an
offspring, will have a (c) value of what?
A

0.2

20
Q

When you set both equations (within the predation model) to zero, what will be plotted?

A

You will plot the isocline of net zero growth.

21
Q

When you set both equations (within the predation model) to zero, what will be plotted?

A

You will plot the isocline of net zero growth.

22
Q

How do plants avoid being eaten?

A

plants will be genetically selected for greater

Resistance & Tolerance

23
Q

What is resistance?

A

something that makes them less likely to be eaten

24
Q

What is tolerance?

A

something that reduces the harm with being eaten

25
Q

What are two examples of plant defenses?

A

Toxins

Digestion-reducing compounds.

26
Q

What are toxic plants more common in the tropics?

A

Tropical areas have more diverse communities of herbivores.

Due to this, there is more selective pressure to develop resistance or tolerance defenses. (thus there is a greater variety of defenses)

27
Q

True or False:

Plants exhibit phenotypic plasticity in response to herbivory

A

True

28
Q

What is phenotypic plasticity?

A

The ability of one genotype to produce more than one phenotype when exposed to different environments.

29
Q

Is phenotypic plasticity short term or long term?

A

It is short term.

30
Q

What is an example of phenotypic plasticity in plants?

A

The increased production of volatile in tomato in response to the infestation of spider mites

31
Q

What are Constitutive defenses?

A

A result of phenotypic plasticity where defenses are produced
continuously, regardless of what happens to the
plant

32
Q

What are Induced defenses

A

A result of phenotypic plasticity where concentrations of a defensive
chemical or morphology increase rapidly in
response to herbivore damage

33
Q

What are the two major ways to avoid going extinct due to predation?

A
  1. Defense
    - Just don’t get eaten in the first place.
  2. Refugia
    - populations are “rescued” from predation pressure by immigration.
34
Q

What is Aposematic coloration?

A

A type of Defense: Camouflage and Coloration

  • bright and conspicuous
    coloration displayed by many toxic or distasteful
    potential prey species
35
Q

What is the advantage of Aposematic coloration?

A

You don’t have to actually be poisonous in order fro predators to think you are poisonous.

36
Q

Is Protection in Numbers a type of Defense?

A

Yes,
Having populations so large that the risk of any one individual being eaten is low.

(just hope that one individual isn’t you)

37
Q

What are the pros and cons of the “Size” defense Strategy?

A

Pros: you’re too big to
be eaten!

Cons: takes a lot of
energy to maintain
large body size

38
Q

What is the Spatial Refugia strategy?

A

diel vertical migration by zooplankton

39
Q

What is the Meta-population rescue Refugia strategy?

A
individuals from
larger populations
may immigrate and
“rescue” smaller
populations
40
Q

What is (b)

A

The capture efficiency of the predator.

41
Q

What is (c)

A

The conversion rate of prey into new predators

42
Q

What is (dp)

A

Death rate of the predators per capita (have to multiply my population)