People And Their Needs

Chapter 12

12.1 A Portrait of Earth• Biomes – The interactions among

organisms and non living factors that give rise to distinct ecosystems.

12.1 A Portrait of Earth Systems and Connections

• Climate is determined primarily by the interaction of air temperature and water.

• Physical laws govern Earth’s systems through matter and energy.

• Ocean circulation, plate tectonics, and global temperature changes all result in dramatic changes in ecosystems.

12.1 A Portrait of Earth

• Earth is a closed system when it comes to matter. Only a tiny bit enters in and leaves.

• Earth is an open system with respects to energy due to the exchange among the sun, Earth, and space.

The sun’s energy powers almost everything on Earth for example:

ocean currentscloud formations

plant growth.

Plate Tectonics is one of the few systems on Earth not powered by

energy from the Sun

12.1 A Portrait of Earth

Perceptions of Earth

• Gaia hypothesis states that Earth functions like a single, living organism that regulates itself to maintain life.

• Earth is thought of as a living organism.

• Gaia hypothesis disagrees with the views of most modern industrial societies.

12.2 Human Societies

• Fully modern Homo sapiens first evolved from ancestral humans about 35000 years ago.

• They were intelligent, artistic (painters), and handy (intricate tools).

12.2 Human SocietiesHunter-Gatherer Societies

• A society in which people gather natural food, hunt, and are nomadic.

•Small impact on the environment because of low population density which allows the environment to regenerate.

•They don’t drain the resources! The environment has time to recover.

12.2 Human SocietiesAgricultural Societies

• A society in which crops are grown and people have time to develop specialized roles.

The invention of the plow led to the expansion of the food supply.

• The early, rapid population growth rate was a result of an increased food supply.

12.2 Human SocietiesAgricultural Societies

• As farming became more productive, more people had the free time to start manufacturing products.

• Societies that fell like the Babylonian Empire were a result of unwise land-use practices resulting in desertification.

12.2 Human SocietiesIndustrial Societies

• A society in which the production of food and other products is performed by machines, demanding large amounts of energy and resources.

• Machines replaced craftspeople.

12.2 Human Societies

Industrial Societies

• The increase of industrialization was accompanied by increased use of fossil fuels.

• Food Supply, Human Population and Manufactured Goods all increased during this time.

12.3 Sustainable DevelopmentThe Sustainable Development Ethic

• An ethic that meets current global human needs without limiting the ability of future generations to meet their own needs.

12.3 Sustainable Development

• Resource – Water, Wind and Sunlight

• Human populations are subject to natural controls.

– Ex. Temperature, Precipitation, Crops, Oxygen

12.3 Sustainable

DevelopmentThe Frontier Ethic

• Founded on the

assumption that human

society is separate from nature.

• Not an Environmentally Friendly Ethic!

• Examples of Frontier Ethic activities would include clear cutting forests, building dams, and draining wetlands.

• Renewable Resources – A resource that regenerates quickly. (Ex. Water, Wood,Sun)

• Nonrenewable Resources – A resource that cannot regenerate quickly. (Ex. Oil, Ores)– They are running out!!!