Population impacts Flashcards
Explain Biocontrol with disease Myxomatosis
-Myxoma virus (dsDNA poxvirus) was used to kill invasive rabbits
True or false: Myxoma virus replicates in vectors
False
-Replicates in rabbit so must be HIGLY VIRULENT
-mechanical transmission
Is the myxoma example frequency or density dependent?
Frequency
What does a density dependent graph look like?
Intersecting lines
-Birth rate line goes down
-Death rate w/ and w/out disease goes upward
-Intersection - new equilibrium
What does a frequency dependent graph look like?
Parallel lines of death w/ disease and w/ out disease
-birth rate goes down
-2 intersections –> equilibrium w/ and w/out disease
Which drives extinction frequency dependent or density dependent
Frequency
What kind of dependent model should we use for bio control?
Frequency dependent with high transmission and virulence
What happened myxoma virus and rabbits?
-Not all rabbits died so resistance occured
-The virus evolved to be less virulent since it was killing rabbots too quicly
Mycoplasma gallisepticum which affects finches is an example of
Density dependent disease
True or false: since Mycoplasma gallisepticum is a density dependent disease it causes extinction in diseases
False
-density dependent does not cause extinction
-populations just stabilize at lower densities
Density dependent does not cause extinction but does what to a population instead?
Lowers population equilibrium
Disease often regulates abundance in natural populations. Effects are dependent on…
Mode of transmission and host-pathogen coevolution
Measles is an example of what kind of dependence
Density dependent
Viruses like Measles fades out when it goes below a certain population, so how do they persist
Coupling
-Populations are imperfectly connected which lets pathogen persist
What would happen to a pathogen/virus in an isolated population compared to a connected one
-Isolated –> goes extinct
-Connected –> persists
