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
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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
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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),