1. Biology Do Now
Directions: Take out a sheet of notebook (Do Now sheet). The students will answer each question based on yesterday’s notes on the nitrogen cycle.
1) What is the purpose of the nitrogen cycle?
2) What do living things need to use nitrogen for? (More than 1 answer)
3) What are the 4 stages or processes nitrogen must go through in the nitrogen cycle?
4) What microscopic organism plays a major role in the nitrogen cycle?

2. Biology Do Now Key
1) What is the purpose of the nitrogen cycle? The purpose of the nitrogen cycle is to convert nitrogen gas (N2), which cannot be used to make proteins into useful nitrogen compounds like ammonia (NH3) and nitrogen oxides like NO2 and NO3 which can be used to make proteins by plants and animals.
2) What do living things need to use nitrogen for? (More than 1 answer) Living things need nitrogen to make DNA, RNA & proteins.
3) What are the 4 stages or processes nitrogen must go through in the nitrogen cycle? The 4 stages are nitrogen fixation, ammonification, nitrification and denitrification.
4) What microscopic organism plays a major role in the nitrogen cycle? Nitrogen-fixing and decomposing bacteria play a major role in the nitrogen cycle.

3. FYI…3-Hour Early Release Day Schedule (~40 min periods)
8:45-9:25 AM Block 1
9:25-10:05 AM Block 2
10:05-10:45 AM Block 3
10:45-11:25 AM Block 4
11:25-12:05  PM Block 5
12:05-12:35 PM LUNCH (Optional)
All Students to the Cafeteria & 
Dismissal from the building beginning PM.

4. Reminders & Announcements
Testing continues for seniors
Senior Finals Week: May 13 – 17, 2019

5. Objective
Students will know how the Earth cycles nitrogen and phosphorus through living and non-living things by taking notes, completing a POGIL on nutrient cycles and answering concept check questions.
Mastery Level: 75% or better on POGIL and exit ticket questions

6. Biogeochemical Cycle Vocabulary Words
Water cycle
Biosphere
Geosphere
Hydrosphere
Atmosphere
Nitrogen cycle
Amino acid
Protein
Nitrogen
Nitrogen-fixing bacteria
Evaporation
Absorption
Condensation
Precipitation
Percolation
Groundwater
Runoff
Root nodules
Nitrification
Decomposition
Phosphorus
Excretion
Erosion
Ingestion

7. Complete your POGIL, if unfinished.
homework

8. Engage – Nitrogen Cycle & Eutrophication
Source:
Eutrophication
Source:

9. Take out notebook paper to take notes
Take out notebook paper to take notes. There are 14 slides of notes and you will get a grade for taking them.

10. What is Nitrogen? Nitrogen makes up about 78% of our atmosphere.
Nitrogen in the atmosphere it is mostly in the form of ______, which is a compound that plants and animals cannot use.
The process of converting nitrogen into compounds that can be used by plants and animals is called the ______________________. N2
Nitrogen Cycle
Slide 1 of 14

11. Why we care about nitrogen…
Nitrogen is an essential component of _____________________.The building blocks of life.
DNA, RNA and Proteins
Slide of 14

12. How does atmospheric nitrogen (N2) get changed into a form that can be used by most living organisms?
Four
By traveling through one of the ________ processes in the Nitrogen Cycle!
(1) Nitrogen Fixation
(4) Denitrification
Nitrogen Cycle
(3) Nitrification
(2) Ammonification
Slide 3 of 14

13. Process 1: Nitrogen Fixation
___________________ is the process in which the N2 compound in the atmosphere breaks and combines with other compounds. The nitrogen is _________ when it combines with ______________ or _______________.
“fixed”
hydrogen
oxygen N N H N2 N H H
Nitrous Oxide (N2O)
Ammonia (NH3)
Slide 4 of 14

14. Three ways to “fix” Nitrogen
bacteria
Main process: Special ____________ convert the nitrogen gas (N2) to ammonia (NH3), which only ________ plants can use (peas, beans).
_________________ strikes convert N2 to N2O or NO3.
Industrial production. ____________ manipulation turns N2 into NH3 (Fertilizer)
some
Lightning
Chemical
Slide 5 of 14

15. Process 2: Ammonification
_____________________ - After all the living organisms have used the ___________________, decomposer bacteria convert the nitrogen to _______________.
Ammonification
organic nitrogen
ammonia H N H H
Ammonia
Bacteria
Slide 6 of 14
Organic Nitrogen (proteins)

16. Process 3: NitrificationH
_______________ is the process that converts ammonia (NH3) into nitrites (NO2) and nitrates (NO3) which ____ plants _______ use.
Note: Ammonia comes from ______ nitrogen fixation and ammonification
How is it done?
_____________________
Nitrification N H H
most
can
Both O O N O N
Bacteria!
Slide 7 of 14 O O

17. Process 4: Denitrification
_______________: Process in which nitrogen compounds _____________________ into atmospheric nitrogen (N2 or N2O).
The main process is performed by _____________________ in the soil. It can also happen by _____________ fossil fuels.
Denitrification
convert back
bacteria
burning N2
NO3
N2O
Slide 8 of 14

18. N2 N2O NO3 NH3 (1) Nitrogen Fixation (4) Denitrification
Nitrogen Cycle
(2) Ammonification
NO3
NH3
(3) Nitrification
Ammonia is converted to nitrites and nitrates.
Nitrates in Soil
Organic nitrogen is converted to ammonia.

19. decomposition by bacteria & fungi
Nitrogen in
the air
nitrogen fixing plant
eg pea, clover
animal protein
plant made
protein
dead plants & animals
urine & feces
denitrifying
bacteria
root nodules
(containing nitrogen
fixing bacteria)
decomposition by bacteria & fungi
nitrates absorbed
nitrates
ammonia
bacteria
nitrites
bacteria
(nitrifying bacteria)

20. Human Impact Combustion Commercial Fertilizers mineral deposits
___________________, releases toxic nitrogen compounds into the atmosphere.
____________________________ release nitrous oxide into the atmosphere and introduce excess nitrogen into the environment.
Remove nitrogen from the soil when we mine it for nitrogen rich __________________________.
Discharge of ___________________________ releases excess nitrogen into the water ecosystems which disrupts the aquatic balance and kills fish.
Commercial Fertilizers
mineral deposits
municipal sewage
Slide 9 of 14

21. Commercial Fertilizers#1
Are the ______ contributor of new nitrogen in the nitrogen cycle.
Added because nitrogen is a ________________ for plant growth.
Problems: hard to apply fertilizer and keep it in one area. Runoff, evaporation, etc.. So farmers apply about ___________________ as they need.
Extra nitrogen disrupts the ________________.
limiting factor
twice as much
food chain
Slide 10 of 14

22. Phosphorus Cycle
The phosphorus cycle may also be referred to as the mineral cycle.
The phosphorus cycle is the movement of phosphorus from the environment to organisms and then back to the environment.
Phosphorus is mainly found in water, soil, and rock.
Phosphorus is essential for life.
Component of DNA
Building block of our bones and teeth.
Slide 11 of 14

23. Phosphorus Cycle

24. Phosphorus Cycle
Unlike the other cycles, phosphorus cannot be found in air in the gaseous state.
The phosphorus cycle is the SLOWEST cycle.
Phosphorus is most commonly found in rock formations and ocean sediments as phosphate salts.
Phosphate salts that are released from rocks through weathering usually dissolve in soil water and will be absorbed by plants.
Slide 12 of 14

25. Phosphorus Cycle
Animals absorb phosphates by eating plants or plant-eating animals.
When animals and plants die, phosphates will return to the soils or oceans again during decomposition.
After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years. Eventually, phosphorus is released again through weathering and the cycle starts over.
Slide 13 of 14

26. Human Impacts on the Phosphorus Cycle
Like nitrogen, increased use of fertilizers increases phosphorus runoff into our waterways and contributes to eeutrophication.
eutrophication.
Slide 14 of 14

27. REMEMBER THIS!!! Most phosphorus is found in rocks and soil.
The phosphorus cycle is the slowest cycle.
Excess phosphorus contributes to eutrophication.

28. Phosphorus Cycle Summary
Now you have learned about the phosphorus cycle, check it out on the:
Phosphorus Cycle Animation

29. Part I. Exit Ticket Questions
1) Explain the major stages of the water, nitrogen and phosphorus cycles.
2) Which cycle is the slowest?
3) Explain the role of nitrogen-fixing bacteria in the nitrogen cycle.
4) What causes eutrophication and how do the nitrogen and phosphorus cycles play a role in eutrophication?
5) Explain how humans play a role in the nitrogen and phosphorus cycles.

30. Part II. Nutrient cycle pogil