Earth's Four Systems

• Earth is divided into four main systems or spheres by scientists.

Earth's Four Systems

• Geosphere (Land): includes rocks, soil, sand.
• Atmosphere (Air): a mixture of gases like nitrogen, oxygen, carbon dioxide, and water vapor.
• Biosphere (Life): includes all living organisms like microorganisms, plants, animals, and humans.
• Hydrosphere (Water): includes all water on Earth, such as fresh and salt water.

Water Importance and Usage

• Humans and animals need water to survive.
• Plants need water to grow.
• Some animals and plants live in water.
• Water affects non-living things, causing erosion and weathering of rocks.
• Weathering: the breaking down of rocks into small particles.
• Erosion: the transportation of small particles to another place.
• Water Uses: generating electricity, preparing food, manufacturing, agriculture, traveling, recreation, cleaning, and bathing.

Water Bodies

• Water is found in rivers, lakes, oceans, seas, and underground.
• Nearly three-quarters (more than 70%) of Earth is covered by water.
• Earth looks like a blue marble because water covers three-quarters of it
• The total amount of water on Earth doesn't change because of the water cycle.

Oceans and Seas

• Oceans and seas are very large water bodies, always containing salt water.

Lakes

• Lakes are water bodies surrounded by land.
• Most lakes contain fresh water, but some contain salt water.

Rivers

• Rivers always flow from a high place to a lower place in a definite path and always contain fresh water.

Groundwater

• Groundwater lies beneath the Earth's surface due to water leakage into the earth through porous rocks and it contains fresh water.
• Water is a renewable resource because of the water cycle.

Water Cycle

• Water on Earth evaporates via sun heat.
• Water vapor rises into the cold air, forming clouds.
• Water returns to Earth's surface as rain during precipitation.

Plants as Renewable Resources

• Plants are renewable because they grow from seeds into new plants that produce new seeds.
• The hydrosphere interacts with the biosphere because living organisms like plants depend on the hydrosphere for survival.

Earth's Systems in Detail

• Earth's systems include the geosphere, biosphere, hydrosphere, and atmosphere.

Geosphere (Lithosphere)

• "Geo" means earth. Includes: rocks,minerals, soils, and landforms (mountains & valleys)
• Molten rocks inside the earth.

Hydrosphere

• "Hydro" means water.
• Includes all water on, under, and above Earth.
• About 71% of Earth is covered by water.
• Water covering Earth: oceans, seas, rivers, groundwater, and glaciers.

Glaciers

• Glaciers are large sheets of ice on Earth's surface.
• Most of Earth's fresh water is in the form of glaciers.
• Salt water makes up about 96.5% of the water on Earth.
• Fresh water makes up about 3.5% of the water.
• Salt water is found in oceans, seas, gulfs (bays), and some lakes.
• Fresh water is found in rivers, rainwater, groundwater, and most lakes.

Atmosphere

• "Atmos" means vapor.
• Includes a mixture of all the gases that surround Earth, such as oxygen, carbon dioxide, and nitrogen.

Biosphere

• "Bio" means life and includes all living organisms on Earth.
• It consists of humans, animals, and plants.

Biome

• A large area of the world that has similar soil, climate, plants, and animals.
• Biome examples include: deserts, forests, rainforests, grassland, and wetlands.

Interactions Between Earth's Systems

• Hydrosphere & Geosphere: erosion of rocks by water, formation of lakes.
• Atmosphere & Biosphere: photosynthesis (plants take CO2, produce O2), respiration.
• Geosphere & Biosphere: soil provides nutrients for plant roots during photosynthesis.
• Hydrosphere & Biosphere: plants, humans, and animals need water to survive; water is a habitat for fish.

Aquatic Ecosystems

• Water ecosystems are also called aquatic ecosystems, which are classified into saltwater and freshwater ecosystems.

Saltwater Ecosystems

• Oceans and seas cover large parts of Earth's surface.
• Shallow areas include coral reefs and intertidal zones.
• Intertidal zones are areas along the coast that disappear underwater at high tide and appear at low tide.
• Deep areas are called abyssal zones.
• Abyssal zones are very deep in oceans so that sunlight cannot reach them.

Saltwater Lakes

• Saltwater lakes do exist.
• Lake Assal saltwater lake located in Djibouti.
• Lake Bardawil saltwater lake located in Egypt

Lake Assal

• Lake Assal has a high concentration of natural salts that result into high concentration of salt.
• Few plants and live there because of salt level.
• There are different bacteria types existing in the lake.

Freshwater Ecosystems

• Include ponds, lakes, and flowing water bodies.

Ponds and Lakes

• Water is present all year in many ponds and lakes.
• Ponds and lakes may dry up because water evaporates faster when the temperature increases in summer.
• Animals and plants adapt because of water evaporation.
• Lake Nasser is a freshwater lake in Egypt.

Flowing Water Bodies

• Rivers and streams are examples of flowing water bodies.

Streams

• Small bodies of flowing water.
• Water is always moving in flowing water bodies.
• Many different plants and animals live in flowing water bodies.

Aquatic Ecosystems Comparison

• Ponds: Freshwater, still water, some plants and frogs
• Streams: Fresh water, running water, catfish and trout
• Oceans/Seas: Saltwater, constantly active water, Kelp, dolphins starfish and Moses fish

Additional Notes

• Oceans and seas include many smaller isolated ecosystems.
• Ocean water circulates around the globe in patterns known as ocean currents.

Explore the interconnectedness of Earth's systems. This learning material covers the geosphere, atmosphere, biosphere, and hydrosphere. Understand the water cycle, natural resources, and the composition of Earth's systems.