1. Bio.2.2 Understand the impact of human activities on the environment.
Populations
Essential Standards
Bio.2.1 Analyze the interdependence of living organisms within their environments.
Bio.2.2 Understand the impact of human activities on the environment.

2. Properties of Populations
Population – group of organisms of same species that live in same place at same time
Characterized:
Size – number of individuals a population has; estimate size
Density – measures how crowded a population is (# individuals per volume)
Dispersion – distribution of individuals within population (clumped, even, or random

3. Population Dynamics
All populations are dynamic – change in size and composition over time
Measure of population:
Birth rate – number of births in period of time
Death rate – number of deaths in period of time
Life expectancy – how long individual is expected to live

4. Population Dynamics
Age Structure – distribution of individuals of different ages in a population

5. Population Dynamics
Survivorship Curves – patterns in mortality at different ages
Type I Curve – chance of death is small early in life but increases later in life
Type II Curve – chance of death is constant
Type III Curve – chance of death is large in early life but decreases later in life

6. Population Growth Rate
Growth rate = Birth rate – Death rate
Change in population size depends on:
Birth and death rates
Immigration – movement of individual into population
Emigration – movement of individuals out of population

7. Population Exponential Model
Exponential Model – rapid increase in a population
Birth rates and death rates would remain constant
Exponential growth – represented by J-shape curve
No limiting factors present!
Limiting Factor – factor that limits growth of a population (ex. Competition, resources, etc.)

8. Population Logistic Model
Logistic Model – builds on exponential model but includes limiting factors
Logistic Curve – represented by S-shape curve
Carrying Capacity – number of species the environment can support over time

9. Population Regulation
Two kinds of population size-limiting factors
Density-independent factors – affects all population the same regardless of size (ex. natural disasters )
Density-dependent factors – limit a population according to population size (ex. Competition, predators, disease)

10. Human population Growth
Hunter-gatherer Lifestyle 10,000 – 12,000 years ago
Steady population size
Agricultural revolution – 10,000 years ago
Slight increase in population
Industrial revolution ~1840
Exponential growth