EE Lecture 25: Intro Population Ecology Flashcards

1
Q

what is the fundamental eqt of population dynamics

A

Nt+1 = Nt + Bt - Dt + It - Et)

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2
Q

what is eqt for exponential growth

A

dN/dt = rN

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3
Q

what are the limitations for the exponential growth eqt

A

only occurs with no competition/predators and excess resources

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4
Q

what does the r stand for in the exponential growth eqt

A

r = intrinsic rate of natural growth (b-d)

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5
Q

define limiting factor

A

syop pops increasing exponentially by reducing growth rate

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6
Q

define regulating factor

A

the subset of limiting factors that bring pops back to eqb,

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7
Q

what are the two sides to regulating factors

A

doesnt only limit pops also makes them recover when rare

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8
Q

how many types of survivorship curves are there

A

3
Type 1 - most individuals survive until old age
II-individuals have a constant chance of dying throughout their lives
III-most individuals die young

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9
Q

give examples of density dependent processes

A

disease
predators
lack of space

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10
Q

what is value of lamda for all pops under favourable condns

what does this lead to

A

lamda > 1

leads to exponential growth

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11
Q

give examples of density independent processes

A

floods
hurricanes
temp
precipitation

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12
Q

are floods density (in)dependent processes?

A

density INDEP

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13
Q

is food a density (in)dependent process

A

density DEP

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14
Q

what does a density independent factor mean

A

their effects on birth and death rates are independent of the number of individuals in the popn

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15
Q

how do you know a factor is density INDEPENDENTq

A

because they dont tend to increase the pop size when small and dont decrease pop size when large

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16
Q

what does density dependent mean

A

a factor that consistently leads to changes in popn growth as a function of density causing BR and DR and dispersal rates to change

17
Q

when is popn regulation said to occurq

A

when one or more density dep factors cause pop size to increase when numbers are low and decrease when numbers are high

18
Q

name some density dep factors

A

food
space
resources

19
Q

what effect do regulation factors have on lamda and r

A

tend to increase lamda and r when pop is small

decrease lamda/r when pop is big

20
Q

which factors can regulate pop size

A

only density dep factors

21
Q

name some pops where density dep has been bserved

A

song sparrow - the number of eggs laid per female decreased with density, as did the number of young that survived long enoughh to become indep of their parents

22
Q

give an example of density dependent mortality

A

highest initial planting densities of soya beans meant most of them died.
eggs of the flour beetle placed in glass tubes - death rate increased as density of eggs per tube increased

23
Q

what happens to a pop if lamda = 1

A

pop stops growing

24
Q

what type of density (in)dependence do flour beetles show

A

show density dependence

as egg density increases, death rate increases

25
what is the logistic eqt of popn ecology
dN/dt = rN ( 1- [N/K])
26
what does the term [1-(N/K)] in the logistic eqt represent
reresents the net effect of factors that reduce the pop growth rate from the constant (r) rate as seen in exponential growth
27
compare logistic growth to exponential growth when densities are low
logistic growth is similar to, but slightly lower than exponential growth when densities are low
28
when densities are low, why is logistic growth similar to, but slightly lower than exponential growth
because when N is small the term (1-N/K) is close to one, and hence a pop that grows logistically, grows at a rate close to r
29
at what point does logistic growth level off
eventually a pop that grows logistically levels off at the carrying capacity = K