Transcript chapter 52 part 1

Bright blue marble spinning in space
Ecology
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Studying organisms in their environment
organism
population
community
ecosystem
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biosphere
Interacting with the environment
 Biotic environment
prey (food)
 competitors
 predators, parasites, disease

 Abiotic environment
sunlight
 temperature
 water
 soil

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organism
population
community
ecosystem
biosphere
Population Ecology
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Life takes place in populations
 Population

group of individuals of same species in
same area at same time
 rely on same
resources
 interact
 interbreed
AP Biology Ecology: What factors affect a population?
Population
Characterizing a Population
 Describing a population


population range
pattern of spacing
 Density (number of
Individuals per unit area or
Volume)
 Dispersion: pattern of spacing
Among individuals within a bound area

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size of population
1970
1966
1964
1960
1965
1961
Equator
1958
1951
1943
1937
1956
1970
Immigration
from Africa
~1900
range
density
Population Range
 Geographical limitations

biotic & abiotic factors
 food, predators, temperature, rainfall, etc.

habitat
adapted to polar region
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adapted to rainforest
At risk populations
 Endangered species

limitations to range / habitat
 places species at risk
Devil’s hole
pupfish
Iiwi
Hawaiian
bird
Socorro
isopod
Iriomote cat
New Guinea
tree
kangaroo
Catalina
Island
mahogany
tree
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Northern white rhinoceros
Population Spacing
 Dispersal patterns within a population
Provides insight into the
environmental associations
& social interactions of
individuals in population
clumped
random
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uniform
Clumped Pattern
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(most common)
Uniform
May result from
direct
interactions
Clumped
patterns
between individuals
in the population
 territoriality
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Random – not common
Unpredictable
spacing
occurs
Clumped
patternsin
the absence of
strong attraction or
repulsions
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Measuring population density
 How do we measure how many
individuals in a population?
number of individuals in an area
 mark & recapture methods

Difficult to count a moving target
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sampling populations
Population Size
 Changes to
population size

adding & removing
individuals from a
population
 birth
 death
 Immigration
 Movement into area
 Emigration
 Movement out of
area
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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 many females at reproductive age in cohort?
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Demography
 Factors that affect growth & decline of
populations

Study of vital statistics & how they change
over time
Why do teenage boys pay high car insurance rates?
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Life Tables
 Age specific summaries of the survival
pattern of a population
females
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males
Life table
What does
this tell you
about the
population?
Survivorship curves
 Graphic representation of life table
The relatively straight lines of the plots indicate relatively constant
rates of death; however, males have a lower survival rate overall
than females.
Belding ground squirrel
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Survivorship curves
 Generalized strategies
Survival per thousand
1000
Human
(type I)
Hydra
(type II)
What do these graphs
tell about survival &
strategy of a species?
I. High death rate in
post-reproductive
years (ie: humans)
100
II. Constant mortality
rate throughout life
span
Oyster
(type III)
10
1
0
25
50
75
Percent of maximum life span
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100
III. Very high early
mortality but the
few survivors then
live long (stay
reproductive)
Age structure
 Relative number of individuals of each age
What do the data imply about population growth in
these countries?
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End Part 1
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