Earth’s Cycles

Students will be able toAnalyze each cycle and state its importance

Water Cycle

Describes the continuous movement of water on Earth

Repeating Cycle (4 steps)1. Evaporation – Water leaves the surface

Mostly the ocean surfaceLakes/streams/snow melt…Plants/animals

Water Cycle

2. CondensationWater gas cools to form liquid (cloud)

3. PrecipitationWater starts to fall back to Earth

Rain, snow, sleet, hail…4. Run off

Water returns to ocean*Most water is found in the ocean*

Rain Shadow

Caused by wind direction andmountain ranges

Explains Denver’s dry climate

Global Weather

Carbon Cycle1. Carbon taken from air by plants

Used for growth to make sugarsMost is used by small ocean plants (plankton)

2. Carbon released into airAnimals digest sugars and release carbon to airDecomposers release carbonBurning of plant material (wood, gasoline…)Volcanic activity

*Most carbon is found in Earth plants/soil/ocean*

Carbon Cycle

Carbon Cycle Effect

Green House EffectWater, CO2, other gases trap heat

Required to prevent water from freezing

Carbon Cycle Problem

Global WarmingOverheating from increased CO2

Concern is that rising ocean temp will change entire world climate

Some places wetter, some drierMelting glacier = rising sea level

Nitrogen CycleSpecial bacteria in soil trap

nitrogen in soil“Nitrogen Fixation”- Key chemical needed to make DNA- Also key component in explosives

Decomposers release nitrogen back to air*Most Nitrogen is found in atmosphere*

Poor Nitrogen Soils

Carnivorous plantsDigest insects for nitrogen

Ozone Layer

Ozone blocks UV lightScientist noticed thinningLinked to chlorofluorocarbons (CFC)

CFC Ban Effect

Quiz

Homework

Pick an Earth cycle and describe how it works. List where the main source would be found in that cycle.