Earth structure Geography

• Geography studies the Earth's surface, encompassing physical features, climate, population, and resources.
• It studies the connections in space between people and their surroundings.
• Physical geography explores the Earth's natural features and processes.

Earth's Structure

• Earth has multiple layers like the crust, mantle, outer core, and inner core.
• The crust is the outermost layer and is solid while being divided into both oceanic and continental types.
• The mantle sits beneath the crust in a semi-molten state.
• The outer core is liquid, while the inner core is solid; both consist mostly of iron and nickel.
• Plate tectonics explains the lithosphere (crust and upper mantle) as plates in motion, causing seismic and volcanic activity, and mountain formation.
• Plate boundaries include convergent (colliding plates), divergent (separating plates), and transform (sliding plates).

Landforms

• Landforms constitute the Earth's natural surface features.
• Mountains are elevated and formed through tectonic and volcanic activity, or erosion.
• Plains are generally flat, found at lower elevations.
• Plateaus are defined as elevated flatlands.
• Valleys are depressions, commonly shaped by rivers or glaciers.
• Deserts are dry areas with little rain and very few plants.
• Coasts mark the boundary of land and sea, shaped by tides and erosion.
• Glaciers erode and deposit sediment as they slowly move over land.

Climate

• Climate is the average weather conditions in a region over a long time.
• Key climate factors: temperature, precipitation, humidity, and wind.
• Climate zones are regions sharing similar climate characteristics (tropical, temperate and polar).
• Latitude affects climate, as the equator gets more sunlight, raising temperatures.
• Altitude affects climate; temperatures drop at higher elevations.
• Ocean currents distribute heat around the planet.
• The greenhouse effect is when atmospheric gases trap heat, which warms the Earth.

Weathering and Erosion

• Weathering is the process of rocks and minerals breaking down on the Earth's surface
• Physical weathering uses mechanical processes such as freeze-thaw cycles and abrasion.
• Chemical weathering uses reactions that alter the chemical structure of rocks.
• Erosion is the removal of weathered material by water, wind, and ice.
• Water erosion includes river, gully, and coastal erosion.
• Wind erosion occurs mainly in dry regions.
• Glacial erosion can create valleys and move large amounts of sediment.

Hydrology

• Hydrology studies Earth's water distribution, movement, and properties.
• The water cycle's stages are evaporation, transpiration, condensation, precipitation, and runoff.
• Rivers, lakes and wetlands, are considered surface water.
• Groundwater is water that is stored in aquifers beneath the Earth's surface.
• Watersheds are areas of land where water drains into shared bodies of water.
• When water exceeds normal capacity, floods occur.

Biogeography

• Biogeography studies the distribution of species and ecosystems across geographic space and time.
• Ecosystems include communities of organisms interacting with their physical environment.
• Biomes are large ecosystems defined by specific climate and plant communities.
• Species distribution is dictated by climate, land shape, soil, and barriers.
• Biodiversity is the variety of life, including genetic, species, and ecosystem diversity.

Soils

• Soil is the topmost layer with minerals, organic matter, water, and air.
• Soil formation is impacted via climate, parent material, land shape, organisms, and time.
• Soil horizons are layers with unique traits in a soil profile.
• Soil texture refers to sand, silt, and clay proportions.
• Soil fertility is when the soil can sustain plant growth.
• Soil erosion damages soil quality and the environment.

Natural Hazards

• Natural hazards are threatening events to life and property.
• Earthquakes are caused by the Earth's crust releasing energy.
• Volcanoes are vents where molten rock, ash, and gas erupt.
• Landslides describe soil and rock moving down a slope.
• Hurricanes are strong tropical cyclones that have winds of at least 74 mph.
• Tornadoes are violently rotating columns of the air.
• Floods are caused by lots of rain, snow melting, or storm surges.
• Droughts are unusually long periods of low rainfall.
• Wildfires are uncontrolled fires in forests, grasslands, and other wildland areas.

Human Impact on the Environment

• Deforestation is the clearing of forest areas for different land use.
• Pollution is contamination of the elements, air, water, and soil, through harmful things, substances.
• Climate change is long-term changes in global temperature and weather, and this happens largely because of people.
• Overpopulation describes when there are too many people beyond what the environment can sustain.
• Resource depletion is consuming resources quicker than they can restore.
• Conservation is caring for and protecting natural resources.
• Sustainability is the action of meeting current needs without jeopardizing future generations.