11-27 Lecture Notes
of 12
Transcript of 11-27 Lecture Notes
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opu a ongrow
o ay sques ons:
II. Whatarethebasicmodelsusedtodescribe
o ulation
rowth?
III. Casestudiesinpopulationgrowth
B.Populationcycles
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I. Whatis
population
ecology?
Membersofthesamepopulationliveinthesamearea
att esametime
Areexposed
to
asimilar
environment/selection
pressures
Interactviaintras ecificcom etition
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II.Whatarethebasicmodelsusedtodescribepopulationgrowth?
240
Dataon
Whooping
Cranes
(WoodBuffaloNatlParkAransasNWR)280
2010
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How fast is the whoo in crane o ulation rowin ?
Totalpopulation=22inearly1940s;now599(11/12)
3wild
populations:
2011
2012
WoodBuffalo 278 300
Floridaresident 20 19
WisconsinFlorida
115
110
Growthrate,over1year
WoodBuffalo
Floridaresident
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Generalizingtheseideas:
LetN0 =populationsizeatstart
1
ThenN N =
isthe
finite
rate
of
increase
IntheWoodBuffaloflock,201112, =
Whatis
if
N1 =250?
Whatis ifN1 =310?
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Rearranging:
N =
N
Ingeneral,Nt =N0t
isan
aggregate
growth
rate,
computed
over
discrete
intervals
(perindividual)basis,computedatanytime?
User to
symbolize
the
per
capita
growth
rate
r =
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r
ratesandinstantaneousrates)
WoodBuffalo
=
r =
= =
Wisconsin
Florida = r
=
Notethatingeneral,Nt =N0 ert
describesdiscrete
rowth r describes
continuousgrowth
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Nt =N0 ert
.
If22individualswerealivein1942and599in2012,what
isr?
Exponentialversusdensitydependentgrowth
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III. Case studies in o ulation rowth
A.Densitydependentgrowth
What's wrong with the graph?
- It doesn't follow the curve.
- There's an overshoot.
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B.Populationcycles
e.g.RedgrouseinEngland;4yearcyclesinabundance
Hypothesis:The
population
crashes
every
four
years
because there is ra id transmission of a arasitic
nematodewormathighpopulationdensity.
Experiment:Incrashyears,catchbirdsattheroost(at
night)andadministeranantiwormmedication.
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Interpretthesegraphs
