Interactions - Predation Dynamics

Question 1

Lotka Volterra Model

Answer 1

This assumes prey consumption rate by a predator is proportional to the prey abundance, so feeding is limited only by amount of prey.

Question 2

Two composed of Lotka-Volterra…

Answer 2

P is amount of predators and N is prey in biomass

Question 3

What type of equation is Lotka-Volterra Model…

Answer 3

Differential equation

Question 4

Assumption of no predators equation…

Answer 4

Exponential increase of prey; dN/dt - rN

Question 5

Denote r

Answer 5

Intrinsic rate of natural increase.

Question 6

What does prey decrease rate depend in presence of predators?

Answer 6

Frequency of prey-predator encounters and numbers of prey and predators present.

Question 7

Successful competition depends on efficiency…

Answer 7

dN/dt = rN - aPN

Question 8

Predator equation of starvation…

Answer 8

dP/dt - -qP

Question 9

Define predator birth…

Answer 9

Rate of food consumption(aPN) and predator efficiency f defines rate of predator birth

Question 10

Equation of predator birth rate…

Answer 10

dP/dt = faPN - qP

Question 11

Zero-growth Isocline

Answer 11

This refers to set of population sized where rate of change for one population in a pair of interaction population in zero.

Question 12

Zero Isoclines

Answer 12

Connecting points of equal gradient in inclination.

Question 13

Lotka-volterra model properties derived…

Answer 13

Zero isoclines where x axis is prey density and predator density the y axis.

Question 14

When is rN = aPN?

Answer 14

When prey rate of increase is dN/dt

Question 15

When is faPN = qP?

Answer 15

When predators dP/dt = 0

Question 16

Predators in a zero isocline…

Answer 16

N being constant, left prey is low and predators decrease, right prey is high and predators increase.

Question 17

Coupled Oscillations

Answer 17

This means changing on regular basis of lots of predators with few prey to lots of prey with few predators.

Question 18

Delayed density dependence effects on lotka-volterra..

Answer 18

Prey may not fluctuate instantly due to reproductive output time delays

Question 19

How does delayed density dependence differ from direct?

Answer 19

Delayed results from a function of the past.

Question 20

Other models of predator-prey fluctuations…

Answer 20

Type 1 functional response
Type 2 functional reponse
Type 3 functional response

Question 21

Type 1 Functional Response

Answer 21

Depicts a linear increase in consumption rate until satation, then no change in consumption rate above satation

Question 22

Why are functional responses better?

Answer 22

Incorporate REAL features into lotka-volterra models.

Question 23

What does Type 1 Functional Response assume?

Answer 23

Consumption rate increases linearly with prey density(a)

Question 24

Type 2 Functional Response

Answer 24

The rate of prey consumption by predator rise as prey density increases, with an eventual asymptote

Question 25

What causes Type 2?

Answer 25

Handling time of the prey(increased prey density increases handling times)

Question 26

Type 3 Functional Response

Answer 26

This is where predators increase their search activity with increasing prey density

Question 27

Mast Years

Answer 27

This is where synchronous production of a large amount of seeds in intermeidated by low production years, commmon in tree species suffering high seed predation.

Question 28

Dynamics of mast years...

Answer 28

In mast years, more chance escaping seed predation, due to satation. Over-production of seeds being energy costly, inhibiting plant growth, re-mediated by following low-growth years.

Question 29

Example of mast years...

Answer 29

The cicads 7-13-17 year cycles.

Question 30

When cicadas are born...

Answer 30

Within 3-4 weeks emerging, adults climb to canopy and feed/mate/oviposit.

Question 31

Why do cicadas cycle in prime numbers?

Answer 31

Because it is harder for predator birth cycles to adapt.

Question 32

Mutual Interference

Answer 32

Is interference among individuals of the same species or population.

Question 33

What limits prey abundance?

Answer 33

Prey or other predators.

Question 34

Ratio Dependence

Answer 34

A type of predator dependence which depends on ratio of prey to predator populations, not on abosolute numbers of either species.

Question 35

Example of competition limiting consumption rate...

Answer 35

Spending more time defending nectar stores, increasing with more competitors there are

Question 36

What does dN/dt = -qP describe?

Answer 36

Rate of change of a population over time to model growth or decline of populations with dN/dt proportional to product of N and per capita rate of resource consumption q

Question 37

What does the the negative sign in dN/dt = -qP indicate?

Answer 37

Population decreases as resources are consumed.

Question 38

What does q represent?

Answer 38

Per capita rate of resource consumption

Question 39

What does dN/dt = -qP suggest?

Answer 39

Rate of change of population is negatively related to resource availability, population size decreasing as resources deplete.

Question 40

What does dP/dt = faPN-qp describe?

Answer 40

Interactions of populations and resources, suggesting population growth rate is influenced by resource availability and conversion efficiency of resource into population growht(as population size increases, per capita rate of resource consumption increase, with decrease in population growth rate.

Question 41

What does -qP represent?

Answer 41

Per capita rate of resource consumption, depending on resource consumption and population size.

Question 42

What does faPn represent?

Answer 42

Per capita rate of population growth due to reproduction, depending on population size, resource availability and resource conversion efficiency?

Question 43

What does f mean in equations?

Answer 43

Per capita rate of population grwoth achieved without resource limitations.

Question 44

What does value f depend on?

Answer 44

Population age structure, reproductive strategies and environmental conditionss.