1. Chapter 5 Characteristics of Populations 5-1 1.Geographic Distribution: “range”, area inhabited by a population 2.Density: # of individuals per unit of area 3.Growth Rate: Increase, Decrease, or Stay the Same

2. Population Growth 3 Factors that affect population growth –# of births (birth rate) –# of deaths (death rate) –# entering and # leaving Immigration: movement of individuals into an area (growth) Emigration: movement of individuals out of an area (decrease)

3. Exponential Growth Exponential Growth: individuals reproduce at a constant rate J curve –Ideal conditions with unlimited resources are necessary for exponential growth. Ex: One bacteria cell reproduces every 20 minutes. How many after 20 min.? How many after another 20 min? How many after one day?

4. Logistic Growth Logistic Growth: when population growth slows or stops (due to decreased availability of resources) S Curve Carrying Capacity: The largest number of individuals that an environment can support

5. 5-2 Limits to Growth Limiting Factor: Causes population growth to decrease 1.Competition 2.Predation 3.Parasitism/Disease 4.Extreme Climates 5.Human Disturbances

6. Density Dependent Factors Density Dependent Limiting Factors – depends on population size and density Factors act most strongly when population is large and dense –Ex: Competition –Ex: Predation –Ex: Parasitism

7. Density-Independent Factors Density –Independent Limiting Factors: affect all populations, regardless of size –EX: weather, natural disaster, seasons, and humans

8. 6-3: Biodiversity Biodiversity: sum total of genetically based variety of all organisms Human threats to biodiversity: –Altering habitats –Hunting to extinction –Pollution –Introducing foreign species to new environments

9. Invasive Species Invasive Species Disaster Pythons in Florida

10. Why is biodiversity important? The greater the VARIATION in an ecosystem, the more likely it is to RECOVER if there is a disruption. –Increased diversity = healthier environment. Biodiversity is a resource –Most pharmaceutical drugs from plants. –Future food sources, building materials, etc… –“Beauty, fascination, & wonder” –Recreation (ecotourism).

11. Threatened –Abundant in range, but decreasing in numbers. –At risk Endangered –Very few remaining in natural range –At risk for going extinct Extinct –Local extinction – gone from local range –Ecological extinction – gone from natural range (in zoos only) –Biological extinction – gone from Earth forever.

12. 1.Habitat Loss –“Hot spots” with greatest impact: tropical areas, coral reefs, wetlands, grasslands, water (fresh & salt) 2.Invasive Species –Organisms not normally in habitat 3.Pollution –Air, water, soil impacts 4.Population –Arrival of humans and exponential population growth 5.Climate Change 6.Overexploitation –Ocean Fisheries HIPPCO – Factors Leading to Species Extinction