POPULATIONS 1

HOW POPULATIONS GROW OBJECTIVES: 5.1 List the characteristics used to describe a population. Identify factors that affect population size? What are exponential growth and logistic growth. 2

Three important characteristics of a population are its geographic distribution, _____, and growth rate. Geographic distribution, or ______, is a term that describes the area inhabited by a population. Population ______ is the number of individuals per unit area. 3

Three factors can affect population size: the number of _____, the number of ______, and the number of individuals that either enter or leave the population. birthsdeathsEntering (leaving) 4

Populations grow if the birthrate is greater than the death rate, or if individuals move into an area (__________). Populations remains the same when the birthrate equals the death rate. Populations decreases when the death rate is greater than the birthrate, or if individuals move out of an area (________). 5

________ growth occurs when the individuals in a population reproduce at a constant rate (only occurs under ____ conditions) ____? Always a J-shaped curve. 6

______ growth occurs when a population’s growth slows or stops following a period of exponential growth. _______ (K) capacity is the largest number of individuals of a population that a given environment can support. Always an S-shaped curve. 7

LIMITS TO GROWTH OBJECTIVES: 5.2 Identify factors that limit population growth. Differentiate (identify the difference) between density-dependent and density-independent limiting factors. 8

A ______ factor (2 types)is a factor that causes population growth to decrease. ______-dependent limiting factor depends on population size (numbers). 1.Competition for resources 2.Predation (predator-prey relationship) 3.Parasitism 4.Disease 9

Density-______factors affect all populations in similar way, regardless of the population. 1.Weather 2.Natural disasters 3.Seasonal cycles 4.Human activities a. damming rivers b. clear cutting forests 10

HUMAN POPULATION GROWTH OBJECTIVES: 5.3 Describe how the size of the human population has changed over time. Explain why population growth rates differ from country to country. 11

Like the populations of many other living organisms, the size of the human population tends to ______ with time. 500 years ago the human population began to grow rapidly. 1. Agriculture and industry made life easier 2. Food supply more reliable. 12

3. Essential goods could be shipped around the world. 4. Improved sanitation 5. Improved medicine and health care _________ is the scientific study of human populations. Demographic _______ is the change in population from a high birth and death rates to low birth and death rates. 13

Age-structure diagrams show the population of country broken down by gender and age group. The table on p.132 predicts that the human population will reach ~9 billion by the year