1. Cycles of Matter What Molecules do Organisms Need? How do Organisms Get Those Molecules?

2. Cycling of MATTER in Ecosystems Organisms need energy AND matter to survive Ex: molecules to build bones, muscle, fat While energy flows in one direction, matter recycles in ecosystems The most important molecules that recycle are water, carbon, nitrogen, phosphorus and oxygen

3. The Water Cycle Water is necessary for organisms to maintain an internal balance and to transport molecules like sugars and enzymes Water is a renewable resource that we access through a water shed Water shed = area of land that catches rain and snow and drains or seeps into a marsh, stream, river, lake or groundwater

4. The Water Cycle Transpiration Evaporation Precipitation Condensation Runoff

5. The Carbon Cycle Required for all living organisms on earth Needed to make DNA, proteins, fats, sugars In nature, found as CO 2 (gas) and many solids (in alive and dead organisms) Photosynthesis and respiration are key processes to keeping the cycle going

6. Photosynthesis and Respiration Photosynthesis (by plants) CO 2 + H 2 O C 6 H 12 O 6 + O 2 Respiration (by most organisms) C 6 H 12 O 6 + O 2 CO 2 + H 2 O Carbon dioxide Water SugarOxygen sunlight Carbon dioxide Water SugarOxygen

7. Photosynthesis and Respiration Matter CYCLES back and forth between photosynthesis and respiration. This is where oxygen is recycled, too!

8. The Carbon Cycle

9. Nitrogen Cycle Nitrogen is a key component of proteins and DNA Nitrogen is present as gas in the atmosphere (N 2 ), and must be turned into a solid (NH 3, NH 4 ) by bacteria for plants to use it Fixing gas into solid = nitrogen fixation Changing solid back into gas = denitrification

10. Nitrogen Cycle

11. The Phosphorus Cycle Phosphorus is an important building block of DNA; all living things must have phosphorus Phosphorus is found in rocks, and enters food webs when plants take up phosphorus found in soil

12. Phosphorus Cycle

13. Water and pH Water has a pH of 7 pH is a scale which determines how acidic or basic a substance is Below 7 = acid Above 7 = base

14. pH Scale

15. The pH Scale Water can split into equal numbers of OH- and H+ ions The pH scale compares everything to water Acidic substances (pH under 7) have more H+ ions than OH- ions Basic substances (pH above 7) have more OH- ions than H+ ions

16. Homework Sec. 3.3, 4.1 and 4.2 (BP, NG, get/don’t get for each section) Bring warm clothes and shoes that can get dirty we will be walking to the pond on Wednesday/Thursday and Friday Mini- Quiz on Wednesday/Thursday  Levels of organization (individual to biosphere)  Trophic levels (energy flow)  Difference between food chain and a food web