Ecosystems: Nature’s Answer to a

Perpetual Motion Machine

Could this ecosphere be considered an “ecosystem”?

I. 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

II. The 2 Energy LawsA. Law of Conservation of Energy

Fire

Steam

Turbine

Transformation

Transformation

(Chemical Energy)

(Heat Energy)

(Mechanical Energy)

Implication: All ecosystems form transformable energy relationships.

“Energy can not be created nor destroyed but can

be transformed into different forms”

Captures “unusable” energy from “inorganic” sources and transforms energy into useable organic form

Main Energy Transformers

Useable chemical energy (organic chemical bonds) passed from one organism to another

Processing Methods

Food Chain

1. Photosynthesis 99%

2. Chemosynthesis 1%Unusable Energy

Usable Energy

Useable Energy

Fire

Steam

Turbine

Transformation

Transformation

(Chemical Energy)

(Heat Energy)

(Mechanical Energy)

B. 2nd Law of Thermodynamics

“In every energy transformation there is a loss of “usable” energy”

Energy Loss (heat)

Energy Lost (heat)

Implication:

1. As energy is passed through an ecosystem, energy is lost.

2. Ecosystem must have a constant unlimited energy source to perpetuate

This Law Explains why:

1. Measured energy flow through an ecosystem forms an “energy pyramid”

2. Food chains tend to be only 4-5 trophic levels

Pyramid of Numbers

Pyramid of Biomass

May not be the most accurate… Why?

Where does the energy go?

How much energy is transferred from one level to the next?

Important Concepts:

1. 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

Pyramid of Net Production

10%

10%

10%

6CO2 + 6H2O C6H12O6 + 6O2

What parts of the world contribute most to primary productivity? Slide 19

2. Net Primary Production: The total amount of carbon made available to the consumers.

Net Primary Production = Gross Primary Production Plant Respiration

3. Secondary Production: The amount of energy converted to actual biomass by a consumer

Gross Primary Production

Net Primary Production

Secondary Production

Abiotic or biotic conditions that restrict productivity in an ecosystem. 4. Limiting Factors: (influence of)

Where on the earth does most of the Net Primary Production take place? Slide 20

Temperature, moisture, soil composition, nitrates and phosphates Slide 17

III. 2 Matter LawsA. 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

Biogeochemical Cycles

Biological Interactions

Geochemical Interactions

Consumers

Producers

Detritivores

Nutrients available to producers

Abiotic reservoir

Geologic processes

The Water Cycle: Required to make “clean” water available for all living things

Evaporation

Precipitation

Condensation

Transpiration

Evaporation

Precipitation

Percolation

Ground Water

Runoff

Condensation

Condensation

PrecipitationEvaporation

Percolation

Transpiration

RunoffGround Water

Human Impact

1. Air Pollutants

a. Nitrates

b. Sulfates

Acid Rain

a. Nitric Acid

b. Sulfuric Acid

The Carbon/Oxygen Cycle: Required for Carbon Building Blocks and Energy

Combustion

CO2 in Atmosphere

Cellular Respiration

Photosynthesis

Primary Consumers

Secondary Consumers

Detritivores

Detritus

Human Impact1. Global Warming (Green House Effect)

2. Deforestation

Anaerobic Decomposition

Fossil Fuels

CO2 + H2O C6H12O6 + O2

C6H12O6 + O2 CO2 + H2O

CO2 in Atmosphere

Food Chains

O2 in Atmosphere

Photosynthesis

Decomposition

Carbon compounds in

water

Plant Primary Producers

PhytoplanktonPrimary

Producers

Waste / Death

The Nitrogen Cycle: Nitrogen Required for Making Proteins

Human Impact:1. Fertilizers2. Sewage

Eutrophication: Overgrowth in lakes

Nitrogen in atmosphere (N2)

Plants

Assimilation

Nitrates (NO3)

Denitrifying Bacteria

Decomposers (bacteria and

fungi)

Ammonification

DeathWaste

Nitrification

Nitrifying Bacteria

Nitrites (NO2)

Ammonium

(NH4+)

Bacteria soil Nitrogen

Fixing

Nitrogen-Fixing bacteria in root

nodules of legumes

Animals

Nitrifying Bacteria

Denitrification

Lightning

(N2)

Food Chains

Ammonifying Bacteria

Ammonia(NH3)

Phosphorus Cycle: Phosphates Required to Make DNA, ATP, Cell Membranes

Animals

Plants

Decomposers

Phosphate in soilLeaching

Dissolved Phosphate

Chemical Precipitatio

n

Waste Death

Sedimentation = new rocks

Geological uplifting

Weathering of phosphate from rocks

Runoff

Organic Phosphate

Inorganic Phosphate

Food Chains

Human Impact:1. Fertilizers2. Sewage

Eutrophication: Overgrowth in lakes

Assimilation

Algae Plants

Decomposition

Summary of Ecosystems

As Matter flows through an Ecosystem, Matter is:

_________________

What are the minimal steps required to have a functional Ecosystem?

As Energy flows through an Ecosystem, energy is:

_________________Lost

Recycled

1. Producers: For energy transformation

2. Detritivores/Decomposers: For recycling

(Red Arrows)

(Blue arrows)

The 5 Laws of Ecology(according to Dr. Barry Commoner)

1. Everything is connected to everything else

2. Everything has to go somewhere

3. There is no such thing as a “free lunch”

4. Nature know best

5. The whole is greater then the sum of its parts

Which laws are being ignored with each of the following issues?1. Ozone depletion

2. Biomagnification of DDT

3. Cultural Eutrophication

4. Acid rain

5. Global warming

6. Smog in cities

7. Polluted Drinking water

8. Human Malnutrition

9. Over Use of Resources

Effect of Limiting Factors in Aquatic Ecosystems

Collection Data Points

(in vitro)

What is the Limiting Factor in this this Ecosystem?Slide 8

Different Ecosystems have Different Productivity Capabilities

1. Which ecosystem is the most productive (g/m /yr) ?2

#2

#1

2. Which Ecosystem provides the earth with the most primary production?

#1

#2

Primary Production of Ecosystems

Slide 7

Regional Annual Net Primary Production For the Earth

Lower Higher

Which Biomes are the Most Productive? Slide 8