1. Chapter 3 The Biosphere Section 3-3; pages 74-80
Cycles of Matter
Chapter 3 The Biosphere
Section 3-3; pages 74-80
Energy Flow & Cycles
Element Cycles
(Revised August 4, 2003)

2. Matter within ecosystems is recycled within and between ecosystems
BIOGEOCHEMICAL CYCLES-connecting the biological, geological, and chemical aspects of the biosphere
Matter Statement:
Matter within ecosystems is recycled within and between ecosystems
BIOGEOCHEMICAL CYCLES
Matter within an ecosystem is recycled.
(diagram of consumer--->decomposer--->soil--->producer--->consumer)

3. BIOGEOCHEMICAL CYCLES
Cycle - water, carbon, oxygen, nitrogen & other elements cycle from the abiotic (“geo” nonliving environment) to biotic (“bio” living organisms) & then back to the environment.
Simply put, biogeochemical cycles pass the same molecules around again and again within the biosphere.
biotic
abiotic
BIOGEOCHEMICAL CYCLES
Water, carbon, oxygen, nitrogen & other elements cycle from the abiotic (“geo” nonliving environment) to biotic (“bio” living organisms) & then back to the environment.

4. BIOGEOCHEMICAL CYCLES
atmosphere
“bank”
Most element cycles have an atmospheric “bank” where the element is found in large amounts.
BIOGEOCHEMICAL CYCLES
(This slide series points out the repeated events in most cycles.)
Most element cycles have an atmospheric “bank” where the element is found in large amounts.
The soil and the ocean are additional major banks for some elements.

5. BIOGEOCHEMICAL CYCLES
RIP
atmosphere
“bank”
Elements move from the “bank” into organisms.
Organisms release elements in daily activities or after death.
BIOGEOCHEMICAL CYCLES
Decomposers (or combustion or erosion) break down organic matter.
What is a result of their actions?
The element is released back into the atmosphere bank.
Decomposers (or combustion or erosion) break down organic matter.
What is the result of their actions?

6. BIOGEOCHEMICAL CYCLES
Three example cycles:
Water
Carbon (carbon-oxygen)
Nitrogen
H2O C N O
BIOGEOCHEMICAL CYCLES
Three example cycles:
Water
Carbon (carbon-oxygen)
Nitrogen

7. WATER CYCLE
evaporation – heating of water from liquid to atmospheric gas.
condensation – cooling of water from vapor to tiny droplets that form clouds.
precipitation – droplets too large to be contained in clouds and water returns to earth as rain, snow, or hail.
transpiration – evaporation of water from leaves of plants.
runoff – excess water from precipitation that comes from streams and rivers and carried to oceans and lakes.
accumulation – collection of water on earth.
(Have the students make a heading for Water Cycle and copy the words with space for) definition.
WATER CYCLE
Use the next diagram to help you define the following:
evaporation
condensation
precipitation
transpiration
runoff
accumulation

8. Refer to Figure 3-11, page 75 Accumulation

9. CARBON CYCLE
The exchange of gases during photosynthesis and respiration is a major example of the living-nonliving cycle of carbon-oxygen.
respiration
photosynthesis O2
CO2
CARBON CYCLE
The exchange of gases during photosynthesis and respiration is a major example of the living-nonliving cycle of carbon-oxygen.

10. CARBON CYCLE How does carbon enter the living part of the cycle?
CO2
CO2
CO2
CO2
CO2
CARBON CYCLE
How does carbon enter the living part of the cycle?
CO2 + H2O ----> C6H12O6 + O2
Carbon enters living portion of the carbon cycle through photosynthesis.
CO2
CO2
CO2
CO2 + H2O ----> C6H12O6 + O2

11. CARBON CYCLE Carbon is returned to the atmosphere environment by:
cellular respiration
erosion
combustion
decomposition
CARBON CYCLE
Carbon returned to environment by:
cellular respiration
erosion
combustion
decomposition

12. CARBON CYCLE
respiration – process where organisms obtain energy from breakdown of glucose.
photosynthesis – plants use light energy (sun) to make glucose.
decomposition – breakdown of dead organic matter.
combustion – burning of fossil fuels (gas, petroleum, coal) which release CO2 into atmosphere.
erosion – runoff of soil into body of water
CARBON CYCLE
Use the next diagram to help you define relationship of the following terms to the carbon cycle.
respiration - CO2 is released back into the atmosphere when food (glucose) is broken down during respiration
photosynthesis - CO2 is taken from the air and trapped into food (glucose) during photosynthesis
decomposition - CO2 is released back into the atmosphere as organic matter is broken down during decomposition
combustion - CO2 is released back into the atmosphere when organic material is burned (undergoes oxidation, similar to respiration )
erosion – CO2 is released back into the atmosphere when erosion breaks down rock such as limestone containing CaCO3 (calcium carbonate)

13. Carbon Cycle Refer to Figure 3-13, page 77

14. N2 free nitrogen NITROGEN CYCLE
79% of the atmosphere is nitrogen gas but it is in a form most living things cannot use. N2
free
nitrogen
NITROGEN CYCLE
79% of the atmosphere is nitrogen gas but it is in a form most living things cannot use.

15. NITROGEN CYCLE
If we can’t take in free nitrogen, how do we acquire it so we can use it in our bodies?
Why do we need nitrogen in our bodies?
NITROGEN CYCLE
If we can’t take in free nitrogen, how do we acquire it so we can use it in our bodies?
Why do we need nitrogen in our bodies?
(Don’t answer these now – they lead to next item.)

16. NITROGEN CYCLE How do we acquire usable nitrogen?
Nitrogen-fixing bacteria convert nitrogen into nitrates.
Plants absorb nitrates.
Animals eat plants.
NITROGEN CYCLE
How do we acquire usable nitrogen?
Nitrogen-fixing bacteria convert nitrogen into nitrates.
Plants absorb nitrates.
Animals eat plants. N2
in air
nitrogen-fixing
bacteria
NITRATES

17. NITROGEN CYCLE How does the nitrogen return to the atmosphere?
Denitrifying bacteria convert the nitrates back into nitrogen.
denitrifying
bacteria
NITROGEN CYCLE
How does the nitrogen return to the atmosphere?
Denitrifying bacteria convert the nitrates back into nitrogen. N2
in air
nitrogen-fixing
bacteria
NITRATES

18. ? NITROGEN CYCLE Why do we need nitrogen? protein Nitrogen
Nitrogen is an essential element for all proteins (amino acids) and nucleic acids. ?
Nitrogen

19. NITROGEN CYCLE Simplified
Free N2 in Atmosphere
denitrifying
bacteria
nitrogen-fixing
bacteria
NITROGEN CYCLE SIMPLIFIED
diagram of nitrogen cycle
Discuss the diagram and have student label on their handout.
RIP
Organic
material
NITRATES

20. NITROGEN CYCLE Simplified
free N2 bank – atmosphere
nitrogen fixation – conversion of atmospheric nitrogen to ammonia
nitrates – converted form of nitrogen from atmosphere.
organisms – living things
organic material – components of living things made of C, H, O, N
denitrification – ammonia and nitrates converted to nitrogen and released back into atmosphere
NITROGEN CYCLE Simplified
Use the next diagram to help you define relationship of the following terms to the nitrogen cycle
free N2 “bank”: Free means pure nitrogen not in any other compound. The “bank” is the atmosphere which is made up of 79% nitrogen.
nitrogen-fixation: nitrogen-fixing bacteria convert free nitrogen into nitrate compounds
nitrates: the form of nitrogen that can can be used by organisms
organisms: Plants take in nitrates and use them in their tissues; animals eat the plants and get the nitrates from their tissues
organic material: Dead organisms, animal waste and organic litter are decomposed by bacteria and other decomposers
denitrification: Denitrifying bacteria convert nitrates from decomposition back into free nitrogen.

21. Refer to Figure 3-14, page 78
N2 in Atmosphere
NO3- & NO2-
NH3

22. All Cycles Are Related All cycles are related.
Diagram showing interaction of water, carbon, nitrogen, sulfur, phosphorus cycles.
Just view that many things are being recycled.
(Do not teach the cycles from this slide at this time. Repeated at end of slide show for review.)