1. Chapter 5 Section 1 How Populations Grow Objectives: -List the characteristics used to describe a population -Identify factors that affect population size -Differentiate between exponential and logistic growth AZ Science Standard: Assess how the size of and the rate of growth of a population are determined by birth and death rate, immigration, emigration, and carrying capacity of the environment.

2. Characteristics used to describe populations: Geographic Distribution: The area inhabited by a population – Described as Squared km Population Density: Number of individuals per unit area Population density = Number of individuals Unit area

3. Population Density Continued Suppose there are 150 bullfrogs living in a pond that covers an area of 3 square kilometers. What is the density of the bullfrog population? Pop. Density = 150 bullfrogs = 50 bullfrogs/km 2 3 km 2

4. Population Growth: Factors that affect population size: – Number of births – Number of deaths – Number of individuals that enter or leave the population (immigration and emigration)

5. Population Growth: Immigration – the movement of individuals into an area Emigration – the movement of individuals out of an area

6. Population Growth Exponential Growth: Growth pattern in which the individuals in a population reproduce at a constant rate Under ideal conditions with unlimited resources, a population will grow exponentially J-Shape curve

7. Exponential Growth

8. Population Growth Logistic Growth: Growth pattern in which a population’s growth rate slows or stops following a period of exponential growth S-shape curve

9. Logistic Growth (S-shaped curve) Carrying Capacity- largest number of individuals of a population that a given environment can support Determined by: Food, nutrients, space, water, etc.

10. # Number of Yeast cells Time (hours) Carrying capacity