Download Carrying Capacity

ECOSYSTEM
ORGANIZATION
And POPULATIONS
OVERVIEW
Ecosystem Organization
 Population is the number of individuals
of the same species in the same place at
the same time.
Factors That Control
Population Growth
 What determines the population
number of an ecosystem (or planet)?
(Think in terms the basics that plants,
animals and ourselves need to survive.)
Limiting Factors
 An environmental factor that causes a
population to decrease
 Food
 Water
 Space
 Weather
4
Other Factors That Control Population
Growth
Other Limiting
Factors:
 Competition
 Predation
 Parasitism
 Crowding
 Stress
 Disease
Carrying Capacity
 The largest population that an area can
support
 A giraffe must eat 10 kg of leaves each day
 The trees in an area can provide 100 kg per
day while remaining healthy
Could 15 giraffes live in this area?
What is the carrying capacity?
6
What dynamics might be involved
in predicting population growth?
Population Size
Population Growth Rate
Carrying Capacity
Limiting Factors
Population Growth Curves
Exponential growth:
70
 Population
60
increases by a
constant
proportion per unit
of time
 At this growth rate
the population
exhibits a J-shaped
curve
50
40
Exponential
30
B
20
10
0
Lag
A
0 1
2
3 4 5
Time
6
Population Growth Curves
 At this growth rate the
population exhibits an
S-shaped curve.
600
500 K carrying capacity
K
400
Population
Logistic growth:
 Population increases
rapidly for a period of
time, its growth begins
to slow, and ultimately,
growth stops.
stabilization
300
200
100
exponential
0
 K (carrying capacity) =
maximum population
size that an environment
can support
lag
0
10
20
Time (in days)
30