Ecosystems

1
Ecosystems Communities

• How Populations Grow

2
How Populations Grow
3
Population Growth

• Key Concept
• Four factors canaffect population size
• Birthrate
• Deathrate
• Immigration
• Emigration

4
Exponential Growth

• Occurs in populations with
• abundant space
• abundant food
• no disease
• no predators

5
Exponential Growth

• Key Concept
• Under ideal conditions,with unlimited
  resources,a population will grow
• exponentially

6
Exponential Growth
ExponentialPhase
7
Logistic Growth

• Key Concept
• As resources become less available, the growth
  of a populationslows or stops.

8
Logistic Growth
Logistic GrowthCharacterized by a S shaped
growth curve.
9
Carrying Capacity

• The largest number of individuals a given
  environment can support.

10
Population Crash

• Dramatic Decrease In The Size Of A Population
  Over A Short Period Of Time.