Major Topics 2.doc

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Published on 14 Sep 2012
School
UTM
Department
Biology
Course
BIO205H5
Professor
BIO205-exam notes
Major Terms
Life tables
oUsed to estimate
age-specific probabilities of
survival
and reproduction
olet us make projections
about population dynamic
ocohort & static
cohort = identify indiv born at same time + keep records from birth
static = record age at death of individual
Lecture Eight – Specific Interactions : Competition
Competition
oWhen individuals use
Same resources
& resources are limited
oAffects
Distribution
& abundance of species
oSpecies exert selective pressure on each other through interactions such as
competition
Pop growth limiting resources competition intra & inter specific
oResources: nutriens, territories, nest sites, mates
oInterspecific = between individuals of DIFFERENT species
oIntraspecific = within individuals of SAME species
o
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BIO205-exam notes
Major Topics
Lecture Six – demography and population dynamics
Life tables
oEstimate abt age-spec prob of survive and repro
oProjections abt pop dynamics
oCohort (record from birth) & static (age at death)
Age distribution
oType of static table
Not cohort, cuz all born at diff times
oWut percentage in wut age category at a snap shot
oReflects history of survival, reproduction, future growth potential
oStable? Growing? Declining?
oOntario
More older than younger
Not replacing themselves
Life expextancy – add on the prob of survival from birth to that age
oForest of white oaks
Coring trees – estimation of age
Dominated by young trees
Thus, older trees being replaced by younger trees
Reproduction is sufficient to replace old trees that die
Age (yrs) vs. percentage of trees
population stable
Vs. cottonwood forest
Dominated by old trees
- absence of young trees population will not
persist
- old trees not replaced
short-term variation in population dynamics evident in age structure
ofinch of Galapagos
ohighly variable climate = much variation in yearly reproductive success &
survival
oage vs. percentage of finches
fairly even distribution of indiv among diff age classes = several
yrs of successful reproduction
age class missing = birds did not nest due to climate of that year
can see that gap/absence of age grp in following years
no 6 yr olds at 1983 (no nesting in 1977)
thus no 10 yr olds at 1987
droughts prevent nesting & reduce number of older birds
abundant rain = population dominant in that year (age class)
how do populations change in size?
oDeath
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BIO205-exam notes
oBirth
oImmigration
oEmigration
All these processes age dependent
oAge spec fecundity
oAge spec mortality
Focus on female they limit population growth
Proportion surviving from birth to x = lx
olx = Sx/S0
o=number of females survivors to age x/ initial total number of females in
pop
Total number of female offspring born to females in x = Fx
Age-specific fecundity (per capita) = mx
omx= Fx/Sx
o=total # of female offsprings born to females in x/ females surviving to age
x
Net reproductive rate = R0
oMean number of female progeny produced per female over her lifetime,
weighted by the prob of survival in each age class
Avg contribution of each female to population
Is each female replacing herself??
oRo = sum of (lx)(mx)
o= sum of (Sx/S0)(Fx/Sx)
oIf R0 < 1 females not replacing themselves declining population
oIf R0 > 1 increasing population
oIf R0 = 1 female just replacing herself stable population size
How can we project pop size in future?
o1. overlapping generations
Daughters start to reproduce/breed while mothers still breeding
Eg. White-tailed deer
Use age spec fecundity & age spec mortality to predict population
dynamics
Graph time vs. sum of survivals to x (sum Sx)
Negative slope = negative growth declining pop size
r = per capita rate of increase.. instantaneous
Sum of Sx can calculate discrete growth rate of a population
oAka geometric rate of increase; discrete growth rate
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