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Colonie High AP Biology DeMarco/Goldberg Populations in their Environmentgoldiesroom.org/AP...
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Colonie High AP Biology DeMarco/Goldberg biosphere ecosystem community population Populations in their Environment organism Chapter 55 Population Ecology population ecosystem community biosphere organism Life Takes Place in Populations Population group of individuals of same species in same area at same time rely on same resources interact interbreed loss of habitat, predation, climatic changes affecting food availability Population Dynamics Complex interaction of biotic & abiotic influences Decline of Northern Pintail First, you need to measure density & dispersion To answer: What environmental factors affect a population? Population Ecology study of populations in relation to environment environmental influences on population density & distribution, age structure, and variations in population size Characterizing a Population Describing a population population range pattern of spacing density size of population 1937 1943 1951 1958 1961 1960 1965 1964 1966 1970 1970 1956 Immigration from Africa ~1900 Equator range density
Transcript of Colonie High AP Biology DeMarco/Goldberg Populations in their Environmentgoldiesroom.org/AP...
Colonie High AP Biology DeMarco/Goldberg
biosphere
ecosystem
community
population
Populations in their Environment
organism
Chapter 55Population Ecology
population
ecosystem
community
biosphere
organism
Life Takes Place in Populations
Population
group of individuals of same species in
same area at same time
rely on same resources
interact
interbreed
loss of habitat, predation, climatic changes affecting food availability
Population Dynamics
Complex interaction of biotic & abiotic
influences
Decline of Northern Pintail
First, you need to measure
density & dispersion
To answer:
What environmental
factors affect a
population?
Population Ecology
study of populations in relation to
environment
environmental influences on population
density & distribution, age structure,
and variations in population size
Characterizing a Population
Describing a population
population range
pattern of spacing
density
size of population
1937
19431951
19581961
196019651964
1966 1970
1970
1956
Immigrationfrom Africa
~1900
Equator
range
density
Colonie High AP Biology DeMarco/Goldberg
Population Range
Geographical limitations
biotic & abiotic factors
food, predators, temperature, rainfall, etc.
habitat
adapted to polar region adapted to rainforest
Changes in Range
Range expansions & contractions
changing environment
Woodlands
Grassland, chaparral,and desert scrub
15,000 years agoglacial period
Alpine tundra
Spruce-fir forests
Mixed conifer forest
0 km
2 km
3 km
1 km
Ele
va
tio
n (
km
)
PresentAlpine tundra
Spruce-fir forests
Mixed conifer forest
Woodlands
Grassland,chaparral, and
desert scrub
result of competition
At Risk Populations
Endangered species
limitations to range / habitat
places species at risk
Socorro isopod
Devil’s holepupfish
Iriomote cat
Northern white rhinoceros
New Guineatree
kangaroo
IiwiHawaiian
bird
Catalina Island
mahoganytree
difficult to count a moving target
Measuring Population Density
How do we measure how many
individuals in a population?
number of individuals in an area
mark & recapture methods
sampling populations
Population Spacing Dispersal patterns within a population
uniform
random
clumped
Provides insight into the
environmental associations
& social interactions of
individuals in population
Population Size
Changes to
population size
adding & removing
individuals from a
population
birth
death
immigration
emigration
Colonie High AP Biology DeMarco/Goldberg
Population Growth Rates
Factors affecting population growth rate
sex ratio
how many females vs. males?
generation time
at what age do females reproduce?
age structure
how females at reproductive age in cohort?
Demography
Factors that affect growth & decline of
populations
vital statistics & how they change over time
females males
Life table
Survivorship Curves Graphic representation of life table
Belding ground squirrel
The relatively straight lines of the plots indicate relatively constant rates of
death; however, males have a lower survival rate overall than females.
Survivorship Curves
Generalized strategiesWhat do these graphs
tell about survival &
strategy of a species?
0 25
1000
100
Human(type I)
Hydra(type II)
Oyster(type III)
10
1
50
Percent of maximum life span
10075
Su
rviv
al p
er
tho
usan
d I. High death rate in post-
reproductive years
II. Constant mortality rate
throughout life span
III. Very high early
mortality but the few
survivors then live long
(stay reproductive)
Trade-offs: Survival vs. Reproduction
The cost of reproduction
increase reproduction may decrease survival
investment per offspring
reproductive events per lifetime
age at first reproduction
Natural
selection favors
a life history
that maximizes
lifetime
reproductive
success
Parental Survival
Kestrel Falcons:
The cost of larger
broods to both male
& female parents
Colonie High AP Biology DeMarco/Goldberg
Reproductive Strategies
K-selected
late reproduction
few offspring
invest a lot in raising offspring
primates
coconut
r-selected
early reproduction
many offspring
little parental care
insects
many plants
K-selected
r-selected
Trade Offsnumber & size of
offspring
vs.
survival of offspring
or parentr-selected
K-selected
“Of course, long before you mature,
most of you will be eaten.”
Population Growth
change in population = births – deaths
Exponential model (ideal conditions)
DN = riNDt
N = # of individuals
r = rate of growth
ri = intrinsic rate
t = time
d(D) = rate of change
growth increasing at constant rate
intrinsic rate = maximum rate of growth
every pair has
4 offspring
every pair has
3 offspring
Exponential Growth Rate
Characteristic of populations without limiting factors
introduced to a new environment or rebounding from a catastrophe
African elephant
protected from hunting
Whooping crane
coming back from near extinction
Carrying Capacity
Can populations continue to grow exponentially?
of course NOT!
what sets limit?
Carrying Capacity (K)
maximum population size that environment can support with no degradation of habitat
not fixed; varies with changes in resources
500
400
300
200
100
0200 10 30 5040 60
Time (days)
Nu
mb
er
of
cla
do
ce
ran
s(p
er
20
0 m
l)
Maximum population size that environment can support with no degradationof habitat
varies with changes in resources
Time (years)1915 1925 1935 1945
10
8
6
4
2
0
Nu
mb
er
of
bre
ed
ing
ma
lefu
r s
ea
ls (
tho
us
an
ds
)
Carrying Capacity
Colonie High AP Biology DeMarco/Goldberg
K =
carrying
capacity
Logistic Rate of Growth
Can populations continue to grow
exponentially?no natural controls
effect of
natural controls
Logistic Model of Growth
Changes in Carrying Capacity
Population cycles
predator – prey
interactions
Regulation of Population Size
Limiting factors
density dependent
food supply, competition
predators
disease
density independent
abiotic factors
sunlight
temperature
rainfall
Isle Royale Studies
Moose population on small island in Lake Superior
wolvesstarvation
winter loss
Introduced Species
Non-native species transplanted populations grow
exponentially in new area
out-compete native species loss of natural controls
lack of predators, parasites, competitors
reduce diversity
examples African honeybee
gypsy moth
zebra mussel
purple loosestrife
snakehead fishkudzu
gypsy moth
Colonie High AP Biology DeMarco/Goldberg
Zebra Mussel
ecological & economic damage
~2 months
Purple Loosestrife
1968 1978
reduces diversity
loss of food & nesting
sites for animals
Snakehead Fish
came to North
America live as
an Asian delicacy
entered North
American rivers
when dumped by
owners
now spreading to
a river near you!
Biological Controls
using an introduced
predator (or other
population growth
inhibitor) to limit the
population of a pest
or other unwanted
species
can backfire as in
case of Bufo
marinus in Australia
Overexploitation
North Atlantic bluefin tuna
Human Population Growth
What factors have contributed to this
exponential growth pattern?
1650500 million
20056 billion
Industrial Revolution
Significant advancesin medicine throughscience and technology
Bubonic plague "Black Death"
20117 billion
Colonie High AP Biology DeMarco/Goldberg
Demographic Comparisons Age Structure
Relative number of individuals of each age
Distribution of Population Growth
1
2
3
Time19501900 2000
Developing countries
2050
4
5
6
7
8
9
10
11
0
Developed countries
Wo
rld
po
pu
lati
on
in
bil
lio
ns
World total
uneven distribution of population:
90% of births are in developing countries
uneven distribution of resources:
wealthiest 20% consumes ~90% of resources
increasing gap between rich & poor
There are choices as
to which future path
the world takes…
The hypothesized
effect of different
income & education
levels…
Ecological Footprint30.2
15.6
6.4
3.7
3.2
2.6
USA
Germany
Brazil
Indonesia
Nigeria
India
Amount of land required to support an individual at standard of living of population
20 4 6 8 1210 14 16 18 20 22 24 26 28 30 32 34
Acres
uneven distribution:
wealthiest 20% of world:
86% consumption of resources
53% of CO2 emissions
over-population or over-consumption?
Ecological Footprint—1997
Based on land & water area used to produce all
resources each country consumes & to absorb all
wastes it generates.
deficit surplus
