module 6.1 predation

Question 1

what is the graph of predation by invasive or novel predators?

Answer 1

lakes with many trout have few frogs and vice versa

Question 2

yellow-legged frogs vs rainbow trout

Answer 2

clear that frog population abundance declines to extremely low levels in the presence of trout (evidence that trout lead to decline of frogs, possibly even extinction)

Question 3

p.caudatum vs their predator, didinium nasutum

Answer 3

no unusual for predators to cause local extinction but since all species are not extinct, there must be some unrecognizable factors that allow coexistence

Question 4

cycling between predators and prey?

Answer 4

Question 5

Question 6

what is the modelling preadtion: lotka-volterra?

Answer 6

-the prey equation: do predator numbers reduce dNp/dt?
-the predator equation: how do prey factor into birth r death rates of predators?
-equilibrium conditions

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

added realism stabilizes exploiter-prey dynamics?

Answer 12

-exploiter-prey model with density dependence in the prey
-exploiter functional responses

Question 13

Question 14

what is the prey equation and the exploiter equation of density dependence on prey?

Answer 14

prey: do predator numbers reduce dNp/dt?
-f=capture rate
-carrying capacity is added to prey population
-change in prey pop=growth of prey-number of prey lost by exploiters
-when set to 0, prey density increases to K when there is no exploiters in the system

predator: how do prey factor in to birth and death rates of predators?
-change in exploiter population density=births possible from prey consumption-natural deaths of exploiters
-cfNp is like the instantaneous per capita birth rate but not constant like b, here the birth rate is dependent on the density of prey
-c=exploiter conversion factor, allows translation of consumed food into a number of offspring
-when 0, nothing to do with exploiter density and solely depends on the prey density

Question 15

Question 16

the predator functional responses

Answer 16

-type 1: in lotka volterra model, but organisms cannot increase their consumption endlessly

-type 2: exploiter consumption levels off at high densities of prey (plateau from gut constraints or handling time that limits how many prey and exploiter can chase, debone or de-shell in a chunk of time) much more common in nature

-type 3: consumption may be slow when prey population densities are very low (longer time for searching) (predators may switch to a more available prey type)
-as prey densities rebound, consumption increases rapidly and eventually levels off to a constant rate once high prey densities are reached

Question 17

what are the four possible outcomes of exploitation?

Answer 17

-prey extinction leads to exploiter extinction
-exploiter extinction surviving prey
-exploiter-prey cycles
-stable coexistence