1.
NITROGEN CYCLE

2.
ENERGY & MATTER
Energy is not the only thing that moves through the ecosystem. Atoms are never destroyed only transformed.
Take a deep breath.
The atoms you just inhaled may have been inhaled by a dinosaur millions of years ago.

3. 6 ATOMS make up 95% of the body in most organisms
OXYGEN
CARBON
HYDROGEN
NITROGEN
PHOSPHORUS
SULFUR
The same molecules are passed around
again and again within the biosphere in
____________________ cycles
BIOGEOCHEMICAL

4. NITROGEN CYCLE ammonia Nitrates & nitrites N2 in Atmosphere
Section 3-3
N2 in Atmosphere
Nitrates
& nitrites
ammonia
BIOLOGY; Miller and Levine; Prentice Hall; 2006

5. WHY IS NITROGEN IMPORTANT?
__________________make DNA and RNA
NITROGEN BASES
Adenine (nitrogen base) is used in _______
ATP
Makes AMINO part of ____________ (proteins)
amino acids
Image by Riedell
Image by Riedell

6. 79% of the atmosphere is made up of NITROGEN gas (N2)
BUT we _____ use the nitrogen gas
we breathe!
The bond in N2 gas is so
strong it can only be broken by
_______________
____________________
CAN’T
lightning
Volcanic activity
few special bacteria
Image by Riedell
Image by Riedell

7. Bacteria that live ______________ and in _________ relationships with
plants called _________, take
nitrogen from the atmosphere and
turn it into ______________, a form
that is usable by plants.
THIS PROCESS
IS CALLED _________________
in the soil
symbiotic
legumes
AMMONIA
NITROGEN FIXATION

8. Other bacteria in the soil convert ammonia into
____________& _______________
which plants can also use.
The nitrogen we need for proteins,
ATP, and nucleic acids comes from
the _____ we eat
____ the____
we breathe!
NITRATES
NITRITES
FOOD
NOT AIR
Image from: and
modified by Riedell

9. Bacteria that live ______________ also carry out the reverse process
________________ → ___________________.
THIS PROCESS
IS CALLED _________________
in the soil
NITRATES & NITRITES
NITROGEN GAS
DENITRIFICATION

10. REVIEW => NITROGEN CYCLE
Why can’t we use the N in the atmosphere?
In what forms do plants absorb Nitrogen?
Name the processes by which N gas is converted into usable forms of nitrogen.
Why is nitrogen important to living organisms?

11. What is it and how does it work?
The Water Cycle
What is it and how does it work?

12. The Water Cycle Precipitation Condensation Water Vapor Transpiration
Evaporation

13. Water Cycle
Water never leaves the Earth. It is constantly being cycled through the atmosphere, ocean, and land. This process, known as the water cycle is driven by energy from the sun. The water cycle is crucial to the existence of life on our planet.

14. Water
The water cycle begins with water. Water is found in many places. A few of them are as follows:
Lakes, rivers, oceans, ponds, puddles, reservoirs, and many other places.

15. Evaporation
The next stage is evaporation. This is a process where the water is heated and turned into a water vapor.
The sun is the main heat source for this process.

16. Condensation
The next stage is condensation. This is where warm and cold air collide and form ice crystals that condense and form droplets of water. These water droplets eventually become to heavy and begin to fall in the form of precipitation.

17. Precipitation
The next stage is Precipitation. This is water falling to the earth in the form of snow, hail, rain, or sleet.

18. Collection
During collection water that falls as precipitation essentially collects as surface water (water you can see above ground) or as ground water (water that collects beneath earth’s surface).

19. Transpiration
The process of evaporation from plants is called transpiration. (In other words, it’s like plants sweating.)

20. Evaporation
If you were to pick the first step of the water cycle, you would start with evaporation. Water everywhere, in lakes, rivers, streams, oceans, puddles, etc. may look like it does nothing, but it is always moving. In the first stage of the water cycle, known as evaporation, the sun’s invisible heat rays heat the water on any surface.

21. Evaporation
This heating of the water changes the composition, or makeup, of the water from the liquid, seen here in the lake, into a gas. The gas form of water, or water vapor, is very light and rises into the air. This leads into the next stage of the water cycle known as condensation.

22. Condensation
During the process of condensation the water vapor (gas) combines in the atmosphere bumping together and forming clusters of molecules of water vapor.

23. Condensation
Once enough water vapor molecules clump together they form a cloud. Clouds are essentially big puffy collections of water and moisture. Once formed as a cloud water changes its composition, or makeup, again from a gas (water vapor) back to a liquid within the cloud itself.

24. Condensation
Eventually the water builds up and builds up within the cloud expanding its size. This is much like a dry sponge once you place it in water. When placed in water a dry sponge soaks up the water and “puffs” up. Once the cloud is full, much like a sponge, the next stage of the water cycle, precipitation, begins.

25. Precipitation
During the process of precipitation, the cloud basically bursts from being too full of water. This causes the water to fall to the ground from the cloud in the from of precipitation. Precipitation can fall to the ground as rain, freezing rain, snow, sleet, and hail.

26. Collection/Percolation
The “last” stage of the water cycle is known as collection. Collection means exactly what its name implies. Water is collected on or in the ground. Water collected on the surface of the ground, as seen as the dark blue oval in the diagram, is called surface water. Surface water can consist of lakes, rivers, streams, oceans, puddles, etc. Any water that can be visibly seen on top of the ground is known as surface water. Water can also be collected underground. Water collected underground is known as ground water. The most common form of ground water that you are familiar with is the water that is absorbed from the ground and makes mud as you dig.
Collected Water

27. Collection/Percolation
Once the water is collected, the whole process starts over again as the sun heats the water and evaporation begins. The water cycle is called a cycle because water is constantly being reused on earth. The process never stops and there are no breaks. If the water cycle ever stopped we would have no water to drink, bathe in , or swim in. This essentially means that you could be drinking the water that George Washington once used to brush his teeth with. Of course it has been cleaned again by nature so it is okay to drink!
Surface Water

28. Review => Water Cycle
Which 2 processes put water into the atmosphere?
How does water return to the earth? In what forms?
Where are some of the places that water collects on/in the earth?
What is transpiration?
Where does transpiration occur?