Physical Geography: Core Concepts and Earth's Structure

• Geography is the study of the Earth's surface, including its physical features, climate, population, and resources
• It bridges the social and physical sciences
• Physical geography focuses on the natural environment

Core Concepts in Physical Geography

• Geomorphology studies Earth's landforms and the processes that shape them
• These processes include weathering, erosion, and tectonic activity
• Climatology is the study of climate and its variability
• It includes analyzing temperature, precipitation, and atmospheric patterns
• Biogeography examines the distribution of species and ecosystems
• It considers factors like climate, soil, and topography
• Hydrology studies water in all its forms
• This includes rivers, lakes, groundwater, and glaciers
• Pedology examines the formation, classification, and mapping of soils
• It considers the physical, chemical, and biological properties of soils

Earth's Structure and Tectonics

• The Earth is composed of several layers: the crust, mantle, and core
• The crust is the outermost layer, divided into oceanic and continental crust
• The mantle is a semi-molten layer beneath the crust
• The core is the Earth's innermost layer, composed mainly of iron and nickel
• Plate tectonics explains the movement of Earth's lithosphere
• The lithosphere is divided into several plates that float on the asthenosphere
• Plate boundaries are sites of earthquakes, volcanoes, and mountain building
• There are three types of plate boundaries: convergent, divergent, and transform
• Convergent boundaries involve plates colliding, leading to subduction or mountain formation
• Divergent boundaries involve plates moving apart, leading to seafloor spreading
• Transform boundaries involve plates sliding past each other horizontally

Weathering and Erosion

• Weathering is the breakdown of rocks at the Earth's surface
• It can be physical (mechanical) or chemical
• Physical weathering includes processes like freeze-thaw and abrasion
• Chemical weathering involves chemical reactions that alter the rock's composition
• Erosion is the removal of weathered material by wind, water, or ice
• Fluvial erosion is erosion by rivers and streams
• Glacial erosion is erosion by glaciers
• Aeolian erosion is erosion by wind

Climate and Atmospheric Processes

• Climate is the long-term average of weather conditions in a region
• Key climate elements include temperature, precipitation, humidity, and wind
• The Earth's climate is influenced by solar radiation, atmospheric circulation, and ocean currents
• The greenhouse effect is the trapping of heat by gases in the atmosphere
• Greenhouse gases include carbon dioxide, methane, and water vapor
• Climate change refers to long-term changes in temperature and precipitation patterns
• Causes of climate change include human activities like burning fossil fuels and deforestation
• Atmospheric circulation patterns are driven by differential heating of the Earth's surface
• These patterns include Hadley cells, Ferrel cells, and Polar cells
• Ocean currents play a crucial role in distributing heat around the globe
• Examples include the Gulf Stream and the El Niño-Southern Oscillation (ENSO)

Hydrological Cycle

• The hydrological cycle describes the movement of water on, above, and below the Earth's surface
• Key processes include evaporation, transpiration, condensation, and precipitation
• Evaporation is the conversion of liquid water to water vapor
• Transpiration is the release of water vapor by plants
• Condensation is the conversion of water vapor to liquid water
• Precipitation is the falling of water in the form of rain, snow, sleet, or hail
• Surface runoff is the flow of water over the land surface
• Groundwater is water stored beneath the Earth's surface

Biomes and Ecosystems

• A biome is a large geographic area characterized by specific climate conditions, animal populations, and plant species
• Major biomes include forests, grasslands, deserts, and tundra
• Forests are characterized by trees and high levels of precipitation
• Grasslands are dominated by grasses and have moderate levels of precipitation
• Deserts are dry regions with sparse vegetation
• Tundra is a cold, treeless biome with permafrost
• An ecosystem is a community of living organisms and their physical environment
• Ecosystems are characterized by the flow of energy and cycling of nutrients
• Food chains and food webs illustrate the flow of energy through an ecosystem

Natural Hazards

• Natural hazards are events that pose a threat to human life and property
• These hazards include earthquakes, volcanoes, floods, droughts, and hurricanes
• Earthquakes are caused by the sudden release of energy in the Earth's crust
• Volcanoes are formed by the eruption of molten rock from the Earth's interior
• Floods are caused by excessive rainfall or the overflow of rivers
• Droughts are prolonged periods of below-average precipitation
• Hurricanes are intense tropical cyclones with high winds and heavy rainfall