1. Resource cycles in ecosystems

2. Cycles  Essential nutrients for living things flow through the ecosystem.  The reservoirs can be in the air, land, or oceans.  Important resources cycle through the living and nonliving parts of ecosystems

3. Biogeochemical Cycle  Energy flows through an ecosystem.  Water and minerals recycle in the ecosystem. Water Nitrogen Water Nitrogen Minerals Calcium Minerals Calcium Carbon Phosphorus Carbon Phosphorus Think: Why the Earth needs a constant influx of energy from the sun, but does not need water from an outside source.

4. Water cycle Availability of water determines productivityAvailability of water determines productivity Water moves from the sky to land as precipitation then back via evaporation 90% of water that evaporates in ecosystem passes through plants.Transpiration: 90% of water that evaporates in ecosystem passes through plants.

5. Carbon cycle  Carbon cycles from atmospheric CO 2 into living things through photosynthesis  CO 2 returns to atmosphere from respiration & burning  Oceans, soils & plants act as a carbon reservoirs Think: What 2 things do humans burn that put CO 2 into the atmosphere.

6. Nitrogen cycle All living organisms need nitrogen (N 2 )All living organisms need nitrogen (N 2 ) 78% of the atmosphere is composed of N 2. which is only usable to a few organisms.78% of the atmosphere is composed of N 2. which is only usable to a few organisms. Nitrogen fixing bacteria take gaseous N 2 & turn it into a liquid or solid form that plants can use.Nitrogen fixing bacteria take gaseous N 2 & turn it into a liquid or solid form that plants can use. Breakdown of organic material results in ammonia.Breakdown of organic material results in ammonia. Nitrogen is returned to the atmosphere when animals and their waste decomposes.Nitrogen is returned to the atmosphere when animals and their waste decomposes.

7. Human impact of natural cycles Human activity such as burning fossil fuels & deforestation has greatly impacted natural nutrient cycles. Causing air, water, and soil pollution.

8. Summary Review Diagram the following cycles: water carbon, and nitrogen then answer the question “ How have humans impacted these cycles?”