1. Ecosystems: Nature’s Answer to a Perpetual Motion Machine
Could this ecosphere be considered an “ecosystem”?

2. Characteristics of an Ecosystem
A. It is the basic unit of Ecology
B. Includes all the interactions of abiotic and biotic factors
C. Must be “self-perpetuating and self- maintaining”
D. All have similar structures due to the 4 unbreakable laws of physics

3. The 2 Energy Laws Law of Conservation of Energy
“Energy can not be created nor destroyed but can
be transformed into different forms”
Turbine
Transformation
(Mechanical Energy)
Implication: All ecosystems form transformable energy relationships.
Steam
(Heat Energy)
Transformation
(Chemical Energy)
Fire

4. Usable Energy Unusable Energy Main Energy Transformers Food Chain
Useable Energy
Useable chemical energy (organic chemical bonds) passed from one organism to another
Food Chain
Main Energy Transformers
Captures “unusable” energy from “inorganic” sources and transforms energy into useable organic form
Usable Energy
Processing Methods
1. Photosynthesis %
Unusable Energy
2. Chemosynthesis 1%

5. B. 2nd Law of Thermodynamics
“In every energy transformation there is a loss of “usable” energy”
Implication:
1. As energy is passed through an ecosystem, energy is lost.
Energy Lost (heat)
Turbine
Transformation
(Mechanical Energy)
2. Ecosystem must have a constant unlimited energy source to perpetuate
Steam
(Heat Energy)
Transformation
Energy Loss (heat)
(Chemical Energy)
Fire

6. This Law Explains why:
Measured energy flow through an ecosystem forms an “energy pyramid”
Pyramid of Numbers
May not be the most accurate… Why?
Pyramid of Biomass
2. Food chains tend to be only 4-5 trophic levels

7. 6CO2 + 6H2O  C6H12O6 + 6O2 Pyramid of Net Production 10% 10% 10%
Where does the energy go?
How much energy is transferred from one level to the next?
Important Concepts:
Gross Primary Production: The amount of energy the producers convert to food by photosynthesis. This can be measured in terms of :
a) amount of CO2 taken from the atmosphere
b) amount of C6H12O6 made
c) amount of O2 produced
What parts of the world contribute most to primary productivity?
Slide 19

8. Net Primary Production
Secondary Production
Net Primary Production
Gross Primary Production
2. Net Primary Production:
The total amount of carbon made available to the consumers.
Net Primary Production = Gross Primary Production Plant Respiration
Where on the earth does most of the Net Primary Production take place?
Slide 20
3. Secondary Production:
The amount of energy converted to actual biomass by a consumer
4. Limiting Factors:
(influence of)
Abiotic or biotic conditions that restrict productivity in an ecosystem.
Temperature, moisture, soil composition, nitrates and phosphates
Slide 17

9. III. 2 Matter Laws A. All matter is made of atoms
Implication: All living things require the same basic atoms
NCHOPS > 98%
Ca, K, Na, Fe, Cl, < 2%
B. Matter can not be created nor destroyed
Implication: All living things must “compete” for atoms.
The limited amount of atoms must recycle through an
ecosystem if the ecosystem is self perpetuating
The Major Biogeochemical Cycles:
Water, Carbon/Oxygen, Nitrogen, Phosphorus

10. Nutrients available to producers
Biogeochemical Cycles
Consumers
Producers
Biological Interactions
Detritivores
Nutrients available to producers
Abiotic reservoir
Geochemical Interactions
Geologic processes

11. The Water Cycle: Required to make “clean” water available for all living things
Human Impact
1. Air Pollutants
a. Nitrates
b. Sulfates
Condensation
Condensation
Evaporation
Precipitation
Evaporation
Precipitation
Acid Rain
a. Nitric Acid
b. Sulfuric Acid
Transpiration
Percolation
Runoff
Ground Water
Evaporation
Condensation
Precipitation
Transpiration
Percolation
Ground Water
Runoff

12. The Carbon/Oxygen Cycle: Required for Carbon Building Blocks and Energy
O2 in Atmosphere
CO2 in Atmosphere
CO2 in Atmosphere
CO2 + H2O  C6H12O6 + O2
Photosynthesis
Cellular Respiration
Photosynthesis
Plant Primary Producers
C6H12O6 + O2  CO2 + H2O
Secondary Consumers
Primary Consumers
Combustion
Phytoplankton
Primary Producers
Food Chains
Waste / Death
Carbon compounds in water
Fossil Fuels
Detritus
Detritivores
Decomposition
Anaerobic Decomposition
1. Global Warming (Green House Effect)
Human Impact
2. Deforestation

13. The Nitrogen Cycle: Nitrogen Required for Making Proteins
Lightning
Nitrogen in atmosphere (N2)
Denitrification
Animals
Plants
Food Chains
Denitrifying Bacteria
Waste
Assimilation
Death
Decomposers (bacteria and fungi)
Nitrates (NO3)
Nitrogen-Fixing bacteria in root nodules of legumes
Nitrification
Ammonification
Nitrifying Bacteria
Ammonium
(NH4+)
Bacteria soil Nitrogen Fixing
Ammonia
(NH3)
Nitrites (NO2)
Ammonifying Bacteria
Nitrifying Bacteria
Human Impact:
1. Fertilizers
Eutrophication: Overgrowth in lakes
2. Sewage

14. Chemical Precipitation
Phosphorus Cycle: Phosphates Required to Make DNA, ATP, Cell Membranes
Inorganic Phosphate
Organic Phosphate
Weathering of phosphate from rocks
Plants
Geological uplifting
Animals
Runoff
Decomposition
Food Chains
Algae Plants
Dissolved Phosphate
Phosphate in soil
Waste Death
Leaching
Assimilation
Decomposers
Chemical Precipitation
Sedimentation = new rocks
Human Impact:
1. Fertilizers
Eutrophication: Overgrowth in lakes
2. Sewage

15. Lost Recycled Summary of Ecosystems
(Red Arrows)
As Energy flows through an Ecosystem, energy is:
_________________
Lost
(Blue arrows)
As Matter flows through an Ecosystem, Matter is:
_________________
Recycled
What are the minimal steps required to have a functional Ecosystem?
1. Producers: For energy transformation
2. Detritivores/Decomposers: For recycling

16. The 5 Laws of Ecology (according to Dr. Barry Commoner)
Everything is connected to everything else
Everything has to go somewhere
There is no such thing as a “free lunch”
Nature know best
The whole is greater then the sum of its parts
Which laws are being ignored with each of the following issues?
Ozone depletion
Biomagnification of DDT
Cultural Eutrophication
Acid rain
Global warming
Smog in cities
Polluted Drinking water
Human Malnutrition
Over Use of Resources

17. Nutrient Addition Experiments in a Hudson Bay Salt Marsh
What are the limiting factors in this Ecosystem?
Slide 18

18. Effect of Limiting Factors in Aquatic Ecosystems
Collection Data Points
(in vitro)
What is the Limiting Factor in this this Ecosystem?
Slide 8

19. Primary Production of Ecosystems
Different Ecosystems have Different Productivity Capabilities #1 #2 #2 #1
1. Which ecosystem is the most productive (g/m /yr) ? 2
2. Which Ecosystem provides the earth with the most primary production?
Slide 7

20. Regional Annual Net Primary Production For the Earth
Lower Higher
Which Biomes are the Most Productive?
Slide 8