Chapter 22 Humans and the Environment

1. Chapter 22Humans and the Environment How do humans impact global systems like the ozone, and global warming? 22.1 notesAn Interconnected Planet

2. Standards • 6.5 – Explain how ecosystems maintain themselves through naturally occurring processes. • 6.6 – Explain how human activities affect the physical and chemical cycles and process of Earth.

3. Earth’s Layers • Earth has three major layers • Geosphere – rock interior tat extends from the molten center to the crust • Hydrosphere – portion of the Earth that is water. • Atmosphere – mixture of gases that surrounds the earth. • 78% N2, 21%O2, 1% other gases (H2O, CO2)

5. Biosphere • Living organisms exist in all three layers. • The biosphere is the part of Earth where life exists.

6. Climate and Atmosphere • Ozone layer is a region of a naturally occurring gas that is about 20 km above Earth’s surface. • It is important because it absorbs most of the radiation from the sun • Energy in changed into heat and can become trapped in the atmosphere. These gases are called greenhouse gases. • The ability of the atmosphere to trap heat is called the greenhouse effect.

7. Section 1 An Interconnected Planet Chapter 22 The Greenhouse Effect

8. A Global Connection • Convention currents affect weather patterns and life forms all around the globe. • Convection currents form when warm air heated by the sun rises and move closer to outer space. Once there, it begins to cool down and sinks back to earth. • This forms a pattern of rising and falling air using a loop called a convection cell. • Groups of convection cells form the system of global air circulation that helps to determine climate.

9. El Nino • El Nino is a weather pattern that forms in December when the normal east-to-west winds do not form over the Pacific Ocean. • When these conditions occur, the warm surface water cuts off the upwelling of nutrients. • With fewer nutrients, the fish populations decline and Peruvian anchovy exports decrease. Fewer anchovies means fewer birds and reduced guano production. • In Australia, a summer drought could lead to reduced grain production. • The south eastern United States gets higher rainfall which boosts its agriculture and reduces forest fires. • El Nino can cause more hurricanes. • It can change the jet stream.

10. Biodiversity • Biodiversity refers to the variety of life in an area. • Species diversity is a measure of the diversity of organisms in an ecosystem. • Species richness and species evenness are terms used to refer to the relative number and kind of organisms of each species in an area. • Genetic diversity refers to the variation of genetic material within all members of a population. • It is important because it affects a population’s ability to adapt to environmental change.

12. Valuing Biodiversity • Biodiversity provides important benefits. • Food for animals • Trees serve as habitats for animals, wood for homes and fuel. • Many plant species are sources of medicines and useful chemicals. • Ecosystems recycle human wastes, including CO2