Populations

I. How Populations grow

A. Describing populations

1. Geographic Range-

Space where it lives

2. Density-# of individuals of a speciesper unit area

3. Distribution-shows how organisms are spreadacross their range

4. Growth Rate- tells whether a population isgetting 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 onhow many individuals are added or removed

1. How?

a. Birthrate/death rate

b. immigration/emigration

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

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

E. Carrying Capacity1) the greatest number of individuals an

Environment can support2) the degree to which a population is

limited in size by its resources

II. Limits to Growth

A. Limiting Factors

Anything that causes the growthOf 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