1. Objectives Summarize the steps of the water cycle in a diagram.
Explain how carbon and oxygen are cycled through an ecosystem.
Describe why nitrogen must cycle through an ecosystem.
Summarize the 3 major conversions of nitrogen in ecosystems.
Explain why it is important that phosphorus be cycled through an ecosystem.

2. Vocabulary
Carbon Cycle
Respiration
Nitrogen cycle
Phosphorus cycle

3. Nutrient Cycles: Objectives
Summarize the steps of the water cycle in a diagram.
Explain how carbon and oxygen are cycled through an ecosystem in the carbon cycle.
Define the steps in the nitrogen cycle.
Summarize the 3 major conversions of nitrogen in the nitrogen cycle.
Be able to define the steps and know how one step impacts the other.
Be able to predict the outcome if one step of a cycle is manipulated (products are removed or skipped).
Do:
Complete the packet in groups. This is your information gathering. Complete by next class.
Complete the cycles handout. This is also due next class.

4. Cycles
Just as organisms are interconnected to each other they are connected to the physical environment as well.
Name several examples of non-living things that organisms, such as yourself, require to live.
Oxygen, water, carbon, nitrogen, and phosphorus are a few examples of these that we will discuss in this section.
Not what roles they play though. We already talked about that in the previous chapter.
You will learn how these substances cycle through the ecosystems so that they may maintain their availability to living organisms.

5. Cycles in Nature
Biogeochemical cycles = Cycles in which water and minerals are recycled and reused by moving from the non-living portion of the environment into living things and back again.
Water Cycle
Carbon Cycle
Nitrogen Cycle

6. Water Cycle
The water cycle continuously moves water between the atmosphere, the land, and the oceans.
We see it first hand in several forms.
Rain falls and is soaked up by the ground, or it pools where it’s drank, or it is absorbed by plants, or it will sit and evaporate back up into the atmosphere.
Since it’s a cycle there is no starting point.
We’ll start with water forming in the atmosphere.

7. In the margin of your notes, identify the steps numbered 1-6.
Condensation

8. Condensation
First, water vapor condenses in the cool air of the sky into the clouds we see.
Even if there’s no clouds there is still plenty of water there.
At any moment, the atmosphere contains an astounding 37.5 million billion gallons of water, in the invisible vapor phase. This is enough water to cover the entire surface of the Earth (land and ocean) with one inch of rain.

9. Precipitation
When enough water accumulates in the atmosphere it collects a water droplets, gets heavy, and falls back to Earth.
This, what we call rain, is also known as precipitation.

10. Run off & Percolation
Some of this water percolates, or is absorbed or soaked into the soil and becomes groundwater.
Other water, called runoff, flows and accumulates across the surface of Earth and runs into rivers, lakes, and oceans.

11. Transpiration & EVAPORATION
Once here if not consumed, the water is heated by the sun and reenters the atmosphere as water vapor by evaporation.
Water also evaporates from trees and plants in a process called transpiration (& animals in perspiration…sweating).

12. In the margin of your notes, identify the steps numbered 1-6.
Condensation 1 2 3 6 4 4 5

13. Nitrogen Cycle
Nitrogen, another essential element, must also be cycled.
The atmosphere is about 78% nitrogen gas, N2. But most organisms cannot use nitrogen gas.
The nitrogen cycle is all about getting the nitrogen in the atmosphere into forms that can be used by organisms.
Recall, Nitrogen is used for
The amino acids of proteins.
In the nitrogenous bases of DNA & RNA
The nitrogen cycle is the process in which nitrogen circulates among the air, soil, water, and organisms in an ecosystem.

14. Nitrogen Cycle
How atmospheric nitrogen gets into the soil so it can be accessed by living things.
In a process called nitrogen fixation, bacteria convert nitrogen gas, N2, into ammonia, NH3.
N2  Nitrogen Fixation (Bacteria)  NH3
Nitrogen-fixing bacteria live in the soil and on the roots of some plants.

15. Nitrogen Cycle
During ammonification, nitrogen from animal waste or decaying bodies is returned to the soil as ammonia by bacteria and decomposers.
How atmospheric nitrogen gets into the soil so it can be accessed by living things.

16. Nitrogen Cycle
During nitrification, ammonia, NH3, is converted to nitrite and then nitrate NO3.
Try not to confuse this with nitrogen fixation.

17. Forms of nitrogen that can be accessed by living things
Nitrogen Cycle
Assimilation is the process in which plants absorb nitrogen. When an animal eats a plant, nitrogen compounds become part of the animal’s body.
Forms of nitrogen that can be accessed by living things

18. Nitrogen Cycle
During denitrification, nitrate, NO3, is changed to nitrogen gas, N2, which returns to the atmosphere.

19. Nitrogen Cycle: On your handouts, label the parts of the cycle.

20. Nitrogen Cycle

21. Nitrogen Cycle: Macro Perspective
Assimilation
Ammonification
Nitrogen fixation
Denitrification
Nitrification

22. Carbon and Oxygen Cycles
Carbon and oxygen are critical for life on Earth, and their cycles are tied closely together.
Just as with water, these are both cycled so organisms always have a supply available.
The carbon cycle is the continuous movement of carbon from the nonliving environment into living things and back.

23. The Carbon Cycle
Starting with atmospheric carbon dioxide, the carbon cycle begins with plants and other autotrophs absorbing CO2 and converting into usable sugars and starches.
This process is known as photosynthesis.

24. The Carbon Cycle Animals then eat this vegetation.
They break down the sugars & starches made by plants and covert it into ATP, the energy of metabolism.
In the process, they release CO2 back into the atmosphere.
This process is called cellular respiration.

25. The Carbon Cycle
All life, plants, animals & everything else, eventually dies.
When it does it is broken down , decays, and collects as fossil fuels.
Fossil fuels, like oil and gasoline, accumulate after millions of years of this process of death and decay.

26. The Carbon Cycle
The burning of this fuel, called combustion, also releases carbon dioxide back into the atmosphere.

27. The Carbon Cycle: on your handouts, label the parts of the cycle.

28. The Carbon Cycle

29. The Carbon Cycle COMBUSTION Man also plays a role.
We are responsible for burning fossil fuels, eating, releasing carbon dioxide, and dying.
These all contribute to the cycling of carbon.
COMBUSTION

30. Concepts Summary
These are the things you have been exposed to and need to know:
What is the difference between food chains and food webs.
Why energy is lost in a food chain.
The 3 main cycles of matter.
Why they are important.
What are the steps in the cycles.

31. 3.. During which of the following months is the rate of photosynthesis greatest? A. May B. March C. January D. September 4. If the data were obtained from the atmosphere over an evergreen forest, the curve likely would A. rise from February to May and fall from August to November. B. vary less throughout the year. C. rise steadily from January to December. D. fall steadily from January to December. 5. If the y-axis of a graph displayed the rate of transpiration of a deciduous forest, the curve likely would B. vary little throughout the year.
Answers
1. Which of the following organisms can transform light energy into chemical energy? A. organism 1 B. organism 4 C. organism 7 D. organism 9 2. If a disease killed off all of organism 2, which of the following organisms would be most affected? A. organism 3 B. organism 7 C. organism 8

32. Phosphorus Cycle
Phosphorus is often found in soil and rock as calcium phosphate, which dissolves in water to form phosphate.
The roots of plants absorb phosphate. Humans and animals that eat the plants reuse the organic phosphorus.
When the humans and animals die, phosphorus is returned to the soil.

33. Phosphorus Cycle
Like water, carbon, oxygen, and nitrogen, phosphorus must be cycled in order for an ecosystem to support life.
Remember, phosphorus is an important element in ATP and DNA.
It must cycle just like the other molecules.
The phosphorus cycle is the movement of phosphorus in different chemical forms from the surroundings to organisms and then back to the surroundings.

34. The Phosphorus Cycle