Earth’s life support systems

• Give characteristics of the Earth’s atmosphere

  . Has a breathable atmosphere

  . It has plenty of oxygen

  . Has a small amount on carbon dioxide

  . It’s atmosphere is kept on the planet by its pull of gravity
• What is the Earth’s climate like?

  The temperature on Earth is not extreme
• Give characteristics of Earth’s water

  . Most important element and is necessary for life

  . It is drinkable

  . It allows life-providing molecules to move around easily
• Give characteristics of Earth’s light and heat

  . The earth is an ideal distance from the sun, so it receives the perfect amount of light and heat to allow life to be created and supported
• What is the Goldilocks zone?

  It’s just the right distance from the sun o allow the presence of liquid water
• Why is life on earth not possible without carbon?

  Due to carbon’s ability to readily form bonds with other atom, giving flexibility to the form and function that biomolecules can take, such as DNA and RNA
• Cryosphere

  The frozen part of the Earth’s surface, including the polar ice caps, continental ice sheets, glaciers, sea ice and permafrost
• Atmosphere

  The envelope of gases surrounding the planet
• Biosphere

  The space at the Earth’s surface and within the atmosphere occupied by living organisms
• Hydrosphere

  All the waters on the earths surface, such as lakes and seas
• Lithosphere

  The rigid outer part of the earth, consisting of the crust and upper mantle. It’s divided into tectonic plates.
• What are the basic three main stores in the global water cycle?

  The atmosphere, oceans and land
• How does water flow between these stores?

  Water flows through the process of:

  . precipitation

  . evapotranspiration

  . run-off

  . groundwater flow
• Closed system

  Input, output and transfer of energy but not matter or mass
• open system

  inputs and outputs of both energy and matter
• What is a drainage basin system?

  An area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean
• How is the drainage basin an open system?

  . The energy comes into and leaves the drainage basin

  . But mass (water, sediment etc.) also enter and leave

  . Therefore it is an open system
• Precipitation

  Form of water that falls from the atmosphere to the Earth’s surface. Moisture in the air condenses to liquid/solid form.
• Evapotranspiration

  The combined process of evaporation and transpiration
• Runoff

  Movement of water over the land surface towards lakes, rivers and oceans
• Interception

  The process by which precipitation is temporarily captured and stored by vegetation before reaching the ground
• Surface storage

  Temporary holding of water on the Earth’s surface
• Soil water storage

  The amount of water retained in the soil after precipitation or irrigation
• Groundwater storage

  The accumulation of water beneath the Earth’s surface stored in the pores and fractures of rocks and sediment layers
• Channel storage

  Volume of water held within the river of stream channels
• Infiltration

  The process by which water on the surface of the ground moves downward into the soil
• Stemflow

  The flow of water in rivers, streams, typically as a result of snow melt, precipitation or groundwater discharge
• Overland flow

  Movement of water across the ground surface
• Channel flow

  Movement of water within the confines of a river, stream or other channels
• Throughflow

  The horizontal movement of water through the soil, in the unsaturated zone above the water table
• Groundwater flow

  The movement of water through the saturated zone beneath the Earth’s surface
• What is residence time?

  The total time that a fluid parcel has spent inside a controlled volume
• What is the global distribution of water stores like?

  Not evenly distributed
• What are the main water stores?

  . Oceans - 97%

  . Polar ice and glaciers - 2%

  . Groundwater (aquifers) - 0.7%

  . Lakes - 0.01%

  . Soils - 0.005%

  . Atmosphere - 0.001%

  . Rivers - 0.0001%

  . Biosphere - 0.00004%
• Why are some stores higher than other?

  Depends on how long the residence time is
• Where is 30% of freshwater stored?

  In rocks deep below the ground surface forming vast underground reservoirs called aquifers
• How many countries possess 60% of the world’s available freshwater supply?

  Less than 10
• What is a drainage basin?

  An area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as lakes or oceans. Vary in size