Chapter 5-1: How Populations Grow

1
Chapter 5-1 How Populations Grow

• Essential Questions
• What are characteristics used to describe a
  population?
• What are factors that affect population size?
• What is exponential and logistic growth of
  populations?

2

• Characteristics of Populations
• Geographic distribution where
• Density - of individuals per unit area
• Growth rate

3

• Population Growth
• 3 factors that affect growth
• of births
• of deaths
• entering or leaving the population
• Immigration entering
• Emigration leaving

4

• Exponential Growth
• Occurs when individuals reproduce _at_ constant rate
• Need ideal conditions w/ unlimited resources
• Graph of exponential growth is a J-curve

5

• Logistic Growth
• As resources become less available, pop. growth
  slows or stops
• Graph of logistic growth is an S-curve
• What slows or stops growth?
• Death rate up, birth rate down, emigration up,
  immigration down
• 4. Carrying capacity largest of individuals
  a given environment can support