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General Ecology Exam #3
Dr. Michael Kingston - Elon University
45
Biology
Undergraduate 4
11/13/2008

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Term
5 Forms of Predation
Definition
Herbivory, Carnivory, Parasitism, Parasitoidism, Cannibalism
Term
Give three reasons to study predation?
Definition
1.It is the major force in structuring communities
2.Keystone predators
3.Coevolution of predators and prey
Term
Two predictions of Lotka-Volterra predation models?
Definition
1.Coexistance
2.Stable limits cycle
Term
6 Assumptions of the Lotka-Volterra predation model?
Definition
1. Predators move randomly amoung a randomly distributed population of prey
2.Every predator prey encounter results in death and consumption of prey
3. Prey exhibits exponential growth in absence of predator
4. All responses of model are instantaneous
5. No model parameters exist to deal with age structure of populations, interaction of prey w/ food supply, or for density dependent mortality of predators
6. predator is not restricted by any limitations other than food supply
Term
Define the life-dinner principle.
Definition
selection will be stronger on the prey than on the predator because a prey individual that loses the race loses its life, whereas the unsuccessful predator loses only a meal.
Term
What ecological factors cause a hump-shaped prey curve like the one of the Rosenzweig and MacArthur model?
Definition
As prey numbers build up, prey begin to limit their own rate of increase due to food shortage, disease, or social interactions.
Term
Assumptions of Rosenzweig and MacArthur Model?
Definition
1. Homogeneous world with no refuges for the prey or different habitats
2. system is one predator eating one prey
3.predator is controlled by something other than food supply
Term
assumption of ratio-dependent model?
Definition
predation rate depends on the ratio of predators to prey rather than the numbers of prey alone.
Term
prediction of ratio-dependent?
Definition
as prey productivity is increased, predator and prey equilibria both rise.
Term
Define endemic growth of prey.
Definition
low density - when prey population size is controlled by the predator.
Term
define epidemic growth of prey.
Definition
high density - when the prey population size overcome the control of the predator
Term
predator pit?
Definition
the lowest region of curve when the lower equilibrium is set by predation
Term
Hollings 4 predator responses to changes in prey population size.
Definition
1.Numerical
2. Functional (type I, II and III)
3.Aggregative
4. Developmental
Term
Numerical functional repsonse?
Definition
increase prey, increase predators via reproduction
Term
Functional response type I?
Definition
at some point, the number of prey eaten per hour becomes constant (usually due to satiation)
Term
type II functional response?
Definition
curved line
Term
type III functional response?
Definition
s shaped curve
Term
handling time?
Definition
the time it takes a predator to catch, kill, and eat its prey
Term
Aggregative Response to changes in prey size?
Definition
movement of predators to areas are higher prey densities.
Term
Developmental response of predators to changes in prey pop. size?
Definition
as predators develop, the number of prey consumed changes
Term
Why does switching occur?
Definition
1. Search image hypothesis
2. Optimal foraging theory
3. marginal value theorem
Term
what is optimal foraging theory?
Definition
that a predator will behaive in such ways that in conserves resources
Term
profitability equation?
Definition
energy value of the prey (E)/ handling time (h)
Term
marginal value theorem?
Definition
predator should leave all patches of prey regardless of profitability when they have been reduced to the same marginal value which is the average for the whole env.
Term
energy maximizers vs. time minimizers
Definition
energy maximizers seek the maximum amount of energy from one feeding (cows) while time minimizers take in a set amount of energy harvested as quickly as possible
Term
additive vs. compensatory mortality
Definition
additive is simply when a predator takes prey at will, whereas compensatory is when a predator takes weak prey that will probably die anyways
Term
prudent predator
Definition
a predator that takes prey that will likely die anyways...not having an effect on population
Term
3 evolutionary responses to predation
Definition
1. Warning (aposematic) coloration
2. Cryptic Coloration
3. Group living
Term
Warning (aposematic) coloration? 2 forms?
Definition
when a prey is brightly colored to warn against dangerous attributes (poisons). One species (mimic) will resemble the other (model). There should be more models than mimics.
Term
Cryptic Coloration?
Definition
when a species camoflages itself or resembles an object
Term
Group living? 3 effects
Definition
when a species herds together for strength in numbers: 1. selfish hypothesis (less predator success rate) 2. Shared vigilance 3. mobbing
Term
define stock
Definition
harvestable sector of population
Term
define yield.
Definition
the number or biomass of organisms harvested per unit time
Term
define recruitment.
Definition
the number of individuals reaching stock size. controlled by birth and growth rate
Term
Russell's equation for stock size
Definition
s1 + R + G - (M + F)
Term
problems with recruitment modeling?
Definition
1. year class failures
2. match/mismatch theory
Term
ludwigs ratchet effect.
Definition
for a fluctuating resource, continuing economic investment and ecological optimism fuel positive feedback that ratchets up the harvest rate to unsustainable levels and causes the eventual collapse of the fishery
Term
5 principles of effective resource management.
Definition
1. include humans as part of the system
2. act before scientific concensus is acheived
3. Rely on scientists to recognize problems, but not to remedy them
4. distrust claims of sustainable resource use
5. confront uncertainty
Term
2 risk aversive strategies for fishermen
Definition
1. adopt harvesting strategies that minimize year class failures (3)
2. impose protected areas "no take zones"
Term
3 harvesting strategies that minimize year class failures
Definition
1.constant quota - catch the same amount every year...on year class failure could result in extinction
2. constant exploitation rate - good years harvest more, bad years harvest less
3. constant escapement - same amount allowed to escape each time
Term
changing ocean hypothesis vs. overfishing hypothesis
Definition
changing ocean hyp is that environmental conditions have changed such as salinity and temperature or predators while overfishing is that the stock was exploited below its recoverable threshold
Term
difference in MSY and OSY
Definition
MSY is the biological approach where replacement growth is the highest, whereas, OSY is the economical approach where there is the greatest difference between total costs and total revenue
Term
difference in logistic model and dynamic pool models.
Definition
logistic do not distinguish amoung growth, recruitment and natural mortality whereas dynamic pool models do.
Term
John Rhythers conclusions on ocean productivity.
Definition
Maximum world fish production is 240 million metric tons per year.
In 1967, total world commercial fish landings were 60 million metric tons and the catch increased at 8 % per year between 1942 and 1967. At this rate, current stocks will be overexploited by 1977.
Future expansion of catches will come from unexploited species from remote regions (e.g., Antarctic krill).
Term
3 Goals of Blue Revolution
Definition
1.Take pressure off wild stocks
2. Generate a net surplus of seafood to feed the world’s population
3. Provide opportunity for economically marginalized groups
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