Earth as a system

Open & Closed Systems

system – defined as a set of parts that work together.

open system – parts can be added or lost

closed system – all parts exist in precise amounts and nothing can be added or lost

Open System Examples

The Human Body

Hockey Teams

Closed system example

A closed jar

Earth – Closed & Open

Closed- all important things such as water, gases, and nutrients exist in limited amounts. They get recycled over and over again. If we use up or deplete these ingredients, we risk upsetting the balance of the entire system.

Open – Heat, radiation, spaceships, debris from space. (incoming and outgoing energy) (shortwave and longwave)

4 Spheres1. Atmosphere – all gases

If earth was the size of a beach ball, theatmospherewould be as thinas a piece of paper.

Atmosphere Processes

Constant movement of air and water through atmosphere and oceans

Drives Earth’s Weather and Climate

Unequal heating of Earth’s land forms and oceans

Earth’s rotation on its axis and its orbital revolution around the sun

Single-cell model

Assumptions: - earth’s surface is uniformly covered in water- The sun is always directly over the equator

(winds will not shift seasonally)- The earth does not rotate (only have to deal

with pressure force)

Single-cell model

Response to the unequal heating of the earth

Coriolis Effect

Three-cell model

Allow earth to spin.

Prevailing winds – Global Patterns -

(January)Add tilt – seasons have an effect! Example: India (cold dry air gets pushed down from the Himalayan mountains) – Result - drought

Prevailing winds – Global Patterns - (July)

Example: Wind patterns reversed – now blow warm moist air from Indian ocean Result: torrential rains and flooding (monsoon season)

4 Spheres2. Biosphere – all living things (Vladmir Vernadsky) - Russian- Divided up into separate

but interdependent units called ecosystems.

- The continuation of life within the biosphere depends on the constant recycling of a number of chemical ingredients called nutrients.

Nutrient Cycles

1) Oxygen Cycle2) Nitrogen Cycle3) Carbon Cycle4) Water Cycle

The Carbon CycleAtmosphere

Plants, Animals, and Soil

Atmosphere

** A very important cycle, even if more than 99 percent of the Earth’s carbon supply is stored in sedimentary rock and in the oceans.

Carbon Cycle

Photosynthesis! Deforestation!- Release of carbon dioxide- http://www.youtube.com/wat

ch?v=7NpTBQFwC8U- http://www.youtube.com/wat

ch?v=unv92gQ4ZAo

Oxygen Cycle

Majority of oxygen in the atmosphere is produced by the respiration of plants. (90% by algae in the world’s oceans)

Plants release this oxygen when they produce carbohydrates during photosynthesis.

Reacts with carbon released by decomposing or burning vegetation or fossil fuels to form CO2

Breathed in by humans & animals and out as CO2

Taken back by plant roots – reverses process of photosynthesis

Nitrogen Cycle

Most plentiful element in Earth’s atmosphere (78%)

Nitrogen – (“Free State”)

Ammonia & Nitrates

Microscopic bacteria living on the roots of certain plants called legumes (alfalfa, peas, and beans)

Proteins

Plant converts

“Fix” free nitrogen

New Proteins – Amino Acids

Animals eat plants and use these proteins and other nitrogen compounds to build amino acids

Nitrogen Cycle

Ammonia & Nitrates

Animals produce waste and die – bacteria begins decomposing amino acid proteins

New Proteins – Amino Acids

Release Nitrogen back into atmosphere in its “free state”

Reabsorbed by plant roots, carried by water to the oceans, or fixed again by bacteria in a reverse process

Denitrification

Deforestation and water cycle…

How is the water cycle affected when a forest is cut down?

4 Spheres3. Lithosphere – soils, rocks, minerals (Earth’s crust)

Rock Cycle

http://www.youtube.com/watch?v=r68iEwYdbh4

Rock Cycle (Pg. 55-56)

Igneous – granite

Sedimentary – sandstone and shale

Metamorphic – marble or slate

- Plates – segments of Earth’s crust which are being pushed apart or together in precise directions and constant speeds.

4 Spheres4. Hydrosphere– all water

Ocean currents

Are similar to the wind patterns Drag of wind on the surface of oceans – primary

cause of currents.Also affected by Coriolis effectHelp to restore energy balance (moving warm

water north and cooler water south) Influence the climate of surrounding areas

Gulf stream

Ocean currents

Tides

Cause – gravitational pull of the moon and sun

Ocean water “piles up” on the side of Earth facing the moon and on the far side of Earth directly opposite the moon. (far side is a result of the centrifugal force of Earth’s rotation) This is high tide. Perpendicular to the high tides are the low tides.

Importance of Tides

Move large amounts of sediment Marshes that become important feeding areas for

many types of fish , shellfish , and waterfowlHydroelectric powerBring Nutrients into coastal areas

Help sustain plant life, provide food for shrimp & crabs

Navigation and shipping Tidal surges could keep harbours clear of ice

buildups

Gaia Hypothesis

British biochemist James Lovelock He believed Earth can be viewed as as single

organism that in 4.6 billion years has developed into a self-regulating system. Ex: an overgrown forest cannot support new life.

Wildfires burn it down, creating room for new growth Gaia (goddess of the Earth) can adapt

Asteroid collisions Earth cannot be destroyed by humans Only concern: how Gaia reacts to the environmental

assault