Earth's Spheres: Geosphere, Atmosphere and Hydrosphere

• The Earth is a complex system composed of four interacting spheres, which makes it the only planet in the solar system known to support life.
• These spheres encompass all land masses, water sources, living organisms, and gases on Earth.

Earth's Four Spheres

• Everything on Earth is categorized into four spheres: geosphere, atmosphere, hydrosphere and biosphere.

Geosphere

• The geosphere includes the Earth itself and consists of rocks, minerals, and landforms.
• The prefix "geo-" means "earth."

Atmosphere

• The atmosphere includes all the gases surrounding the Earth.
• The prefix "atmo-" means "air."
• Earth's atmosphere has a combination of gases crucial for sustaining life.
• Air in our atmosphere consists of 78% Nitrogen and 21% Oxygen.

Hydrosphere

• The hydrosphere contains all water on Earth: oceans, rivers, lakes, groundwater, and frozen water like glaciers.
• The prefix "hydro-" means "water."
• Oceans hold 97% of the Earth's water.
• Water is essential for life, consituting about 90% of living things.

Biosphere

• The biosphere encompasses all living things on Earth, including animals, plants, and microorganisms.
• The prefix "bio-" means "life".

Sphere Interactions

• The four spheres interact and influence each other through the circulation of energy and matter.
• An event in one sphere often causes changes in other spheres, creating a two-way cause and effect relationship called an interaction.

Hydrosphere Details

• Approximately 70% of Earth's surface is covered by water, which is the hydrosphere.
• The hydrosphere includes surface water, underground water, and water in the air.
• Water shapes the Earth's surface, influences weather, and is essential for life.

States of Water

• Water exists in three states: liquid, solid (ice), and gas (water vapor).
• Liquid water forms rivers, lakes, and oceans due to gravity.
• Water vapor is an invisible gas present in the atmosphere and is inhaled with every breath.

Types of Water

• Saltwater contains salt, primarily sodium chloride, and is found in oceans, seas, and some lakes/groundwater.
• Freshwater has low amounts of salts and is found in glaciers, lakes, rivers, and groundwater; is also essential for humans.

Geosphere Details

• The Earth is made mostly of solid, rocky material, which constitutes the geosphere.
• The geosphere consist of the ocean floors, deserts, rocks, mountains and land formations on the continents.
• The geosphere includes non-living parts of soils and animal skeletons that become fossilized.

Earth's Layers

• The Earth consists of layers: the crust, mantle, outer core, and inner core.

Crust

• This is the outermost layer of the Earth made of soil water and rock, and is the one living beings inhabit.
• The crust is the thinnest layer.

Mantle

• Located under the crust, the mantle makes up the thickest layer of the Earth, at about 3000km thick.
• The Earth's crust floats on this and is a hot layer that is part melted (magma) and part solid.

Core

• It is made of the outer core and the inner core
• Outer core: made of boiling hot lava and liquid iron and nickel with a thickness of 2200km
• Inner core: a hot, dense ball of solid iron and is the hottest layer of the Earth due to high pressure.

Tectonic Plates

• The geosphere is constantly moving due to Earth's internal heat, which causes currents in the mantle.
• The Earth's crust is made of interlocking plates called tectonic plates.
• Tectonic plates move across the Earth's surface through convergent, divergent, and transform movements.

Convergent Plate Boundaries

• Landforms created by convergent plate boundaries are big mountains and deep ocean trenches.
• When an oceanic plate collides with a continental plate, a trench is created as the heavier plate goes under the lighter one.
• Mountains are formed when two continental plates meet and push up.
• Natural hazards include earthquakes and volcanoes due to plate movement and magma formation.

Divergent Plate Boundaries

• Divergent plate boundaries create new ocean floor and rift valleys.
• Magma rises and cools to form new land when plates move apart under the ocean.
• A rift valley, a large crack where land is pulling apart, can form on land.
• Natural hazards include earthquakes weaker than those at convergent boundaries, and volcanoes from rising magma.

Transform Plate Boundaries

• These boundaries are known for ground shifts as the plates slide past each other.
• The main natural hazard is earthquakes, caused by plates getting stuck and suddenly releasing.
• An example is the San Andreas Fault in California.

Atmosphere Composition and Function

• The atmosphere surrounding the planet is formed by the force of Earth's gravity pulling gas molecules into layers composed of nitrogen (78%) and oxygen (21%), plus water vapor and other elements.
• The atmosphere provides oxygen, carbon dioxide, regulates temperature (greenhouse effect), and protects from harmful rays and space debris.
• The atmosphere also regulates the temperature on Earth.

Atmosphere Layers & Ozone

• The atmosphere layers are distinguished by temperature changes and differences in air molecule density.
• The ozone layer protects the Earth from harmful UVB rays.

Biosphere Details

• The biosphere includes all life on Earth in the oceans, caves, mountain tops, and the atmosphere.
• It overlaps with all other Earth spheres.
• It consists of over 300,000 plant types and millions of animal species.
• An individual organism is the smallest level of the biosphere.
• A population represents all individuals of the same species.
• A community is a group of different populations living in the same area.
• An ecosystem includes a community of interacting organisms and their environment.
• A biome is an area classified by the species that live there.
• A biosphere is all of the living organisms on a planet.
• Biomes are classified as terrestrial (land) or aquatic (water), varying from one region to another.
• Earth has six major biomes: forest, grassland, freshwater, marine, desert, and tundra.

The Earth comprises four interacting spheres: geosphere, atmosphere, hydrosphere, and biosphere which support life. The geosphere includes rocks, minerals, and landforms, while the atmosphere contains gases like Nitrogen and Oxygen. The hydrosphere encompasses all water sources, including oceans and rivers.