Populations

I. How Populations grow A. Describing populations 1. Geographic Range- Space where it lives

2.Density-# of individuals of a species per unit area

3.Distribution-shows how organisms are spread across their range

4. Growth Rate- tells whether a population is getting bigger, smaller or staying the same

5.Age structure-#s of males and females in different age groups of a population

B.Population Growth-changes based on how many individuals are added or removed 1. How? a. Birthrate/death rate b. immigration/emigration

C.Exponential Growth-the larger a population grows, the more quickly it grows—graph looks like a J

D.Logistic growth-a growth pattern in which a Population’s growth rate slows down or stops following a period of exponential growth---graph shaped Like an S

E. Carrying Capacity 1) the greatest number of individuals an Environment can support 2) the degree to which a population is limited in size by its resources

II. Limits to Growth A. Limiting Factors Anything that causes the growth Of a population to decrease Ex: food, predators

1. Density-Dependent Limiting factors a. Depends on population size 1. predator-prey cycle

2. herbivores

3. Parasites and disease

4. Competition

5. Overcrowding

2. Density Independent Factors Affects populations regardless of size Ex: weather, natural disasters

III. Human Population growth A. Historical Overview

B. Patterns of Human population Growth 1.Demography - the scientific study of human populations

2. Demographic Transition- A change from high birth rates and death rates to low birthrates and death rates

3.Age structure

4. Future Population growth