1. T ODAY ’ S A GENDA : 8/22 – 23/ 13 Write one relevant word for each letter in: Ecology WALT & WILF; routines Review “find someone who” safety Review expectations and syllabus Pre-test: Biogeochemical cycles Read 18.4 in text, complete active reading ws TILA & SID Homework: Read National Geographic Article (Nitrogen), text mark and answer questions Safety Test in two cycles!

2. B IOGEOCHEMICAL C YCLES Biology 1 Honors topic 1.1

3. C YCLES All matter cycles...it is neither created nor destroyed... As the Earth is essentially a closed system with respect to matter, we can say that all matter on Earth cycles.

4. C YCLES Biogeochemical cycles: the movement (or cycling) of matter through a system.

5. C YCLES by matter we mean: elements carbon nitrogen oxygen molecules water

6. C YCLES We will focus on three biogeochemical cycles: Hydrologic (water) cycle Carbon cycle Nitrogen cycle These are the cycles in which humans interact the most.

8. C ARBON C YCLE The carbon cycle is one of the most important to humans because it is important to our existence: -- one of the primary elements forming human tissues -- necessary to plants, the basis of human food

9. C ARBON C YCLE

10. The carbon cycle is also important to humans because it is 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.

11. C ARBON C YCLE photosynthesis is the basis of life on Earth... carbon dioxide + water + sunlight → organic material (sugar) + oxygen

12. C ARBON C YCLE

13. animals and plants respire, releasing energy for other activities decay is also a form of respiration

14. N ITROGEN C YCLE Important cycle because: -- nitrogen is a necessary nutrient -- nitrogen is part of acid rain

15. N ITROGEN C YCLE

16. Important Terms: Limiting Nutrient - Amount of an element necessary for plant life is in short supply Nitrogen Fixation - Chemical conversion of N 2 to more reactive forms, e.g. NH 3 (ammonia) or NO 3 - (nitrate) Denitrification - Chemical conversion from nitrate (NO 3 - ) back to N 2

17. C ITATIONS : http://www.colorado.edu/GeolSci/courses/GEOL10 70/chap04/chapter4.html http://www.education.noaa.gov/Freshwater/Wate r_Cycle.html https://spark.ucar.edu/carbon-cycle-diagram-doe http://www.eo.ucar.edu/kids/green/cycles7.htm