2.  Carbon  Oxygen  Hydrogen  ????

3.  Living things need nitrogen to make amino acids, which make up proteins  Nitrogen is part of nucleotides, which make DNA and RNA

4.  Air  78% nitrogen  21% oxygen  0.02% carbon dioxide  <1% other gases  Plants and animals cannot absorb nitrogen from the air  What problem does this pose for living things?

5.  How does nitrogen get into living organisms?  What suggestions do you have? How can you imagine that living things could convert nitrogen into a form that they can use?

7.  Miracle-Gro is made with ammonium phosphate, urea, potassium chloride, and other ingredients  Total Nitrogen: 15%  Available phosphate: 30%;

8.  The fertilizer is added to the soil and the plants absorb it  What about plants in the wild? Where does their nitrogen come from?  Waste from other living things

9.  They cannot absorb it from soil or from the air  They cannot use ammonia or nitrates to make amino acids  Animals get nitrogen from eating plants

10.  Decomposers break down the dead tissue and add it to the soil  The plants have the nitrogen available to them

11.  Everyone please take a handout

12.  Most nitrogen is released as ammonia NH3 (in urine and other waste)  Some is absorbed directly by plants  Some is converted to nitrate (NO3) by bacteria (called nitrifying bacteria)  Plants can use nitrate (NO3)

13.  Ammonia to nitrite  NH3 to NO2 by nitrifying bacteria  Plants cannot absorb NO2 so another step is needed  NO2 (nitrite) to NO3 (nitrate) by nitrifying bacteria  Plants can absorb and use nitrate (NO3)

14.  Denitrifying bacteria  They convert NO2 and NO3 back into N2 which is released back into the atmosphere

15.  A different bacteria, called nitrogen fixing bacteria  These bacteria are found mainly in the roots of legumes (peas, soybeans, clover, alfalfa)

17.  If there is not enough ammonia in the soil, these bacteria can make ammonia from the N2 in the air

18.  There are living things that need nitrogen and other living things that are able to convert the nitrogen from the air to a form that is usable by plants.  Also, the remaining nitrogen can be returned to the air

19.  How does the flow of matter in ecosystems compare with the flow of energy through ecosystems?  Matter (atoms) are recycled and none are lost  Energy is lost in the energy pyramid and must be replenished

21.  What does it mean to rotate crops?  Why do you think that farmers would alternate crops, especially between legumes and non-legumes?

22.  Due Thursday: Worksheet as review for the unit 2 test  Due Friday: First draft for the introduction section of the bottle ecosystem lab  It will also serve as a review for the exam  Web site has all the topics that should be included