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Seasons, Solar Intensity, and Latitude • Factors that affect solar energy: Earth’s rotation, Earth’s revolution around the sun, tilt of the Earth’s axis, and atmospheric conditions. • Summer: greatest solar radiation, occurs in the Northern Hemisphere. • Winter: hemisphere is tilted away from the sun. • Earth is closer to the sun in the Northern Hemisphere during the winter than in the summer. Soil • Thin layer: basic natural resource and deeply affects every other part of the ecosystem. • A good soil for growing most plants should have about 45% minerals( mixture of sand, silt, and clay), 5% organic matter, 25% air, and 25% water. • Soils develops in response to several factors: Parent material, Climate, Living organisms, Topography. Page 73. Soil Components • Clay: Very fine particles. Low permeability to water, therefore, upper layers become waterlogged. • Gravel: course particles. Consists of rock fragments. • Loam: equal mixture of clay, sand, silt, and humus. Rich in nutrients. • Sand: Sedimentary material coarser than silt. Water flows through quickly for most crops. • Silt: Sedimentary material consisting of very fine particles between the size of sand and clay. Organic vs Inorganic Fertilizers • Three common forms: manure, green manure, and compost. Improves soil texture, adds organic nitrogen, and benefits bacteria and fungi. • Improves water holding capacity of soil. • Helps prevent erosion Inorganic Fertilizers • Does not add humus to soil, less ability to hold water. • Lowers oxygen content of the soil • Supplies a limited number of nutrients, usually nitrogen and phosphorus. • Requires large amount of energy to produce, transport, and apply. • Releases nitrous oxides, a green house gas. Soil food web • A community of organisms living all parts of their soil. Describes a complex living system in the soil and how it interacts with the environment, plants, and animals. • See diagram on p. 76 Erosion • Movement of weathered rock or soil from one place to another. Caused by flowing water, wind and human activities. • Examples: deforestation, construction and burning of natural vegetation. • Poor agricultural techniques also lead to significant droughts. Three Types • Sheet erosion: soil moves off as a horizontal layer • Rill erosion: fast flowing water cuts channels in the soil • Gully erosion: extreme case of rill erosion, where over time, channels increase in size and depth. Soil erosion • • • • Look up the following definitions: Desertification Salinization Waterlogging Landslides and Mudslides • Landslides: occur when masses of rock, earth, or debris move down a slope. • Mudslides: common type of fast moving landslide that tends to flow in channels. They are caused by disturbances in the natural stability of a slope. • Mudslides usually begin on steep slopes and can be triggered by natural disasters. Areas affected by landslides and mudslides • Where wildfires and construction have occurred • Steep slopes and bottom of slopes and canyons. • Construction of buildings and roads. • Channels along streams or rivers. • Surface runoffs . Review notes • • • • • • • • • • • • • • Majority of the rock in the Earth’s surface. Know examples of igneous rocks, metamorphic, and sedimentary. Acid rain and its effect on soil. Types of soils and its amount Examples of volcanoes, Earthquakes, Tsunamis, and Erosion Know the different types of plates. Dust Bowl of 1930’s, geological times ( Paleogene, Neogene, Jurassic, Cretaceous, and Permian). Types of Rocks (sedimentary, metamorphic, and Igneous) Elements in the Earth’s crust. Make sure to identify the A,B,C,D, and O layers. Review the different types of waves, richter scale, and seismogram. Study the St. Andreas Fault and Mt. St. Helen. Topics for the essays: Plate Tectonics, mudslides, landslides, earthquakes, tsunamis, parts of the earth’s crust, hot spots, lithosphere, asthenosphere, and sea floor spreading. Study the three different types of boundaries( transform, divergent, and convergent),