1. ECOSYSTEM RECYCLING Material Cycles

2. As energy & matter move through ecosystem matter must be recycle and reused Types of Cycle 1. Carbon & Oxygen Cycles 2. Water Cycle 3. Nitrogen Cycle

3. Carbon & Oxygen cycle Involves the process of photosynthesis & respiration  Photosynthesis uses CO 2 and produces O 2  Respiration use O 2 and produces CO 2 Different meanings of the word respiration 1. Cellular Respiration (carbon cycle talks about this)  All living things do this 2. Breathing with lungs and mouth (only some do this)

4. The carbon cycle is one of the most important to humans because it is important to our existence:  One of the major elements forming human tissues  Necessary to plants, the basis of human food  Important to the climate system which sets the background for our environment:  Carbon dioxide (CO 2 ) and methane (CH 4 ) are greenhouse gases which help set global temperatures

7. Human influences on carbon cycle In last 150 years atmospheric CO 2 has risen 30% This is caused by burning fossil fuels  Factories and cars Also by burning forests (to clear land for agriculture)  Now less vegetation is available to absorb CO 2 from atmosphere through photosynthesis  The burning also releases more CO 2 Increased levels CO 2 is causing global climate change

8. Water Cycle Availability of water is one of the key factors that determine the productivity of a terrestrial/land ecosystem Water is found in bodies of water, atmosphere, the ground and living organisms Involves Photosynthesis & Respiration Transpiration Transpiration (movement of water through a plant) Evaporation & Condensation Excretion

9. Heat causes water to EVAPORATE from bodies of water, soil and organisms  TRANSPIRATION is when water evaporates from plants Water leaves the atmosphere through PRECIPITATION

10. Nitrogen Cycle Organisms need nitrogen to make amino acids, proteins and nucleic acids. The nitrogen gas in the air is in a form that is not usable! Nitrogen fixing bacteria—transform nitrogen gas into a usable form  Live in soil and inside swellings on roots of certain plants (mutualism) Involves decomposers and other soil bacteria which break down and convert nitrogenous (urine) wastes and the remains of dead organisms into material that is usable by autotrophs (nitrates) Another type of bacteria will return nitrogen gas to atmosphere (denitrification)