5-1 HOW POPULATIONS GROW 5-2 LIMITS TO GROWTH 5-3 HUMAN POPULATION GROWTH 6-2 RENEWABLE AND NONRENEWABLE RESOURCES Ch 5 Populations

5-1 How Populations Grow Three important characteristics of a population are its geographic distribution, density, and growth rate Population Density is the number of individuals per unit area

5-1 How Populations Grow Three factors can affect population size:  Number of Births  Number of Deaths  Number of individuals that enter or leave the population Immigration- movement of individuals into an area Emigration- movement of individuals out of an area

5-1 How Populations Grow Exponential Growth occurs when the individuals in a population reproduce at a constant rate Under ideal conditions with unlimited resources, a population will grow exponentially

5-1 How Populations Grow As resources become less available, the growth of a population slows or stops Logistic Growth occurs when a population’s growth slows or stops following a period of exponential growth The maximum number of individuals is considered the Carrying Capacity of the population Pg 123 (1-6)

5-2 Limits to Growth A Limiting Factor is a factor that causes population growth to decrease

5-2 Limits to Growth A limiting factor that depends on population size is called a Density-Dependent limiting factor  Examples include  Competition  Predation  Parasitism  Disease Predator-Prey Relationships are the best known way that populations are controlled through interactions

5-2 Limits to Growth Density-independent limiting factors affect all populations in similar ways, regardless of the population size Unusual weather, natural disasters, season cycles, and certain human activities such as damming rivers and clear cutting forests are all examples of density- independent limiting factors

5-3 Human Population Growth Like the Populations of many other living organisms, the size of the human population tends to increase with time

5-3 Human Population Growth The scientific study of human populations is called Demography Birthrates, death rates, and the age structure of a population help predict why some countries have high growth rates while other countries grow more slowly

5-3 Human Population Growth Dramatic change in birth and death rates leads to Demographic Transition Age structure diagrams show the population broken down by gender and age group  More adults live longer with better health and medicine

Pg 127 (1-4) Read Pg 128- In a paragraph decide whether the federal government should change the status of the gray wolf Pg 132 (1-5)

6-2 Renewable and Nonrenewable resources Environmental goods and services may be classified as either renewable or nonrenewable resources Renewable resources can regenerate if they are alive or can be replenished by biochemical cycles if they are nonliving A Nonrenewable resource is one that cannot be replenished by natural processes

6-2 Renewable and Nonrenewable resources Sustainable development is a way of using natural resources without depleting them and of providing for human needs without causing long-term environmental harm Human activities can affect the quality and supply of renewable resources such as  Land  Forests  Fisheries  Air  Fresh Water

6-2 Renewable and Nonrenewable resources Land Resources:  Plowing the land removes roots that holds the soil in place leading to an increase in the Soil Erosion or wearing away of surface soil  Farming, overgrazing, drought has turned once productive areas into deserts called Desertification Forest Resources:  Deforestation is cutting down trees which leads to erosion and long term effects on soil

6-2 Renewable and Nonrenewable resources Fishery Resources  Aquaculture is raising aquatic animals for human consumption to help prevent overfishing Air Resources  Smog is a mixture of chemicals from automobile and factory emissions  A Pollutant is a harmful material that can enter the biosphere through the land, air, or water  Pollutants can drift miles to be collected and fall to the Earth as Acid Rain

6-2 Renewable and Nonrenewable resources Freshwater Resources:  Pollution threatens the billions of water used daily for everything from drinking to washing clothes to water crops Pg 149 (1-5)