PCE - 5 Flashcards
how does competition create differences?
evolution of traits that minimise overlap of habitat/ resource use
why is predation important in ecology?
affects structure and dynamics of communities
why is predation important in evolution?
affects morphology, physiology, behaviour
why is predation important in agriculture?
the need for pest control; pesticides
why is predation important in conservation?
predator control vs. reintroductions;
pesticides
why is predation important in biodiversity?
has an affect on richness, eveness, diversity, gradients
what are the components of the optimal foraging theory?
- Objective: maximise profitability (energy/time)
- Currency: unit to maximise (energy etc) profitability (energy/time)
- Constraints: search time and handling time (cant search will handling cant eat while searching)
what is the equation for diet breadth - when an organism should add a new item to their diet?
profit of new prey >= cost of ignoring new prey and searching for another of most profitable
what is diet breadth (contigency model of foraging)?
- Choose most profitable, ignoring search costs.
- Add items until the profit of new items is less the average cost of searching and handling items currently in the diet
What are the two constraints that determine
whether an item is included in the diet?
handling and search time
what is the definition of random eating?
eat in proportion to what is available
does profitability = abundance?
no
what does prey death function =?
= predator growth function
- conversion of prey into predators
what is a functional response?
how predator consumption varies with prey density
what does consumption rate by predator =
= mortality rate for the prey
what are the 3 functional responses?
1) Constant Mortality Rate
2) Mortality Rate DECREASES with Density
3) Mortality Rate INCREASES then DECREASES with
Density
describe type 1 function response?
consumption rate and prey density increase exponentially - the gradient is constant therefore prey mortality is also constant - straight line
describe type 2 function response?
inverse density dependent mortality - no negative feedback in prey mortality
- most common
describe type 3 function response?
logistic model - density dependence is acting- negative feedback - gradient increases then reaches inflection point and starts decreasing
what is the recipe (outcome of species interactions)?
1) choose a growth function (exponential or logistic)
2) choose a functional response (type 1, 2 or 3)
3) convert the functional response to numerical (multiply by 10%)
4) choose a predator death function
what 3 affects can predation have on diversity?
1) Keystone predation increases diversity
2) Generalist predation can decrease diversity
3) Predation can change ranking of competitors, but not change diversity
