Earth as a system

1. Earth as a system

2. 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

3. Open System Examples Hockey Teams The Human Body

4. Closed system example A closed jar

5. 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)

6. 4 Spheres • Atmosphere – all gases If earth was the size of a beach ball, the atmosphere would be as thin as a piece of paper.

7. Atmosphere Processes Earth’s rotation on its axis and its orbital revolution around the sun Constant movement of air and water through atmosphere and oceans Unequal heating of Earth’s land forms and oceans Drives Earth’s Weather and Climate

8. 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)

9. Single-cell model Response to the unequal heating of the earth

10. Coriolis Effect

11. Three-cell model • Allow earth to spin.

12. 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

13. Prevailing winds – Global Patterns - (July) Example: Wind patterns reversed – now blow warm moist air from Indian ocean Result: torrential rains and flooding (monsoon season)

14. 4 Spheres 2. Biosphere – all living things (VladmirVernadsky) - 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.

15. Nutrient Cycles • Oxygen Cycle • Nitrogen Cycle • Carbon Cycle • Water Cycle

16. The Carbon Cycle Atmosphere 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.

18. Carbon Cycle • Photosynthesis! • Deforestation! • Release of carbon dioxide • http://www.youtube.com/watch?v=7NpTBQFwC8U • http://www.youtube.com/watch?v=unv92gQ4ZAo

19. 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

20. Nitrogen Cycle • Most plentiful element in Earth’s atmosphere (78%) Nitrogen – (“Free State”) Microscopic bacteria living on the roots of certain plants called legumes (alfalfa, peas, and beans) “Fix” free nitrogen Ammonia & Nitrates Plant converts Proteins Animals eat plants and use these proteins and other nitrogen compounds to build amino acids New Proteins – Amino Acids

21. Nitrogen Cycle New Proteins – Amino Acids Animals produce waste and die – bacteria begins decomposing amino acid proteins Ammonia & Nitrates Reabsorbed by plant roots, carried by water to the oceans, or fixed again by bacteria in a reverse process Release Nitrogen back into atmosphere in its “free state” Denitrification

23. Deforestation and water cycle… • How is the water cycle affected when a forest is cut down?

24. 4 Spheres 3. Lithosphere – soils, rocks, minerals (Earth’s crust)

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

26. Rock Cycle (Pg. 55-56) Igneous – granite Sedimentary – sandstone and shale Metamorphic – marble or slate

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

29. 4 Spheres 4. Hydrosphere– all water

30. Ocean currents • Are similar to the wind patterns • Drag of wind on the surface of oceans – primary cause of currents. • Also affected by Coriolis effect • Help to restore energy balance (moving warm water north and cooler water south) • Influence the climate of surrounding areas • Gulf stream

31. Ocean currents

32. 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.

33. Importance of Tides • Move large amounts of sediment • Marshes that become important feeding areas for many types of fish , shellfish , and waterfowl • Hydroelectric power • Bring 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

34. 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