Environmental Science: Toward a Sustainable Future Richard T. Wright

1
Environmental Science Toward a Sustainable
Future Richard T. Wright
Chapter 3

• Ecosystems How They Work
• PPT by Clark E. Adams

2
Ecosystems Function Transfer Energy and Nutrients

• Matter, energy, and life
• Energy flow in ecosystems
• The cycling of matter in ecosystems
• Implications for human societies

3
Matter, Energy, and Life

• Matter in living and nonliving systems
• Energy basics
• Energy changes in organisms

4
Environmental Spheres
5
Elements of Life
Organic carbon-based molecules Examples
C6H12O6, CH4 Inorganic molecules without
carboncarbon or carbonhydrogen
bonds Examples NaCl, NH4, H2SO4
6
Elements of Life
92 naturally occurring elements Elements Found
in Living Organisms N CHOPS (macronutrients) C
HOPKINS Ca Fe Mg B Mn Cu Cl Mo Zn What elements
would be harmful to living organisms?
7
Atmospheric Gases
78 Nitrogen
21 Oxygen
lt0.04 Carbon Dioxide
8
Match the Elements (Left) with Molecules (Right)

• Nitrogen
• Carbon
• Hydrogen
• Oxygen
• Phosphorus
• Sulfur

• Glucose
• Proteins
• Starch
• Fats
• Nucleic acids
• All of the above

9
Matter and Energy

• Matter anything that occupies space and has mass
• Cannot be created or destroyed
• Can be changed from one form into another
• Can be recycled
• Can be measured where gravity is present

10
Matter and Energy

• Energy anything that has the ability to move
  matter has no mass and does not occupy space
• Cannot be created or destroyed
• Can be changed from one form to another
• Cannot be recycled
• Can be measured

11
Laws of Thermodynamics
First Law (CHANGE) Energy is neither created
nor destroyed but may be converted from one
form to another. NO FREE LUNCHES! Second Law
(LOSS) In any energy conversion, you will end up
with less usable energy than you started with.
YOU CANT BREAK EVEN!
12
Entropy Energy Changes in Organisms

• Systems will go spontaneously in one direction
  only, which is toward increasing entropy..

13
Example of the Laws of Conservation of Matter and
Thermodynamics
Global Warming
Acid Rain
Smog
14
Ecosystems Use Sunlight As Their Source of Energy
15
Conservation of Matter and Energy Capture
16
Food Assimilation in Consumers
17
Match Outcomes (Left) with Process (Right)

• Releases O2
• Stores energy
• Releases CO2
• Uses CO2
• Releases energy
• Produces sugar
• Uses sugar
• Uses O2

• Photosynthesis
• Cell respiration
• Both
• Neither

18
Match Outcomes (Left) with Organisms (Right)

• Releases O2
• Stores energy
• Releases CO2
• Uses CO2
• Releases energy
• Produces sugar
• Uses sugar
• Uses O2

• Plants
• Animals
• Both
• Neither

19
Energy Flow in Ecosystems

• Primary production
• Energy flow and efficiency
• Running on solar energy
• Freely available
• Nonpolluting
• Everlasting

20
Productivity of Different Ecosystems
21
Energy Flow through Trophic Levels
10,000 Kcal
Producer
22
Energy Flow through Trophic Levels
23
The Cycling of Matter in Ecosystems

• The carbon cycle
• The phosphorus cycle
• The nitrogen cycle

24
The Carbon Cycle

• How and in what form does carbon enter and leave
  the cycle?
• How is the role of autotrophs and heterotrophs
  different and the same?
• What are the human impacts on the cycle?

25
(No Transcript)
26
The Phosphorus Cycle

• How and in what form(s) does phosphorus enter and
  leave the cycle?
• How is the role of autotrophs and heterotrophs
  different and the same?
• What are the human impacts on the cycle?

27
(No Transcript)
28
The Nitrogen Cycle

• How and in what form(s) does nitrogen enter and
  leave the cycle?
• How is the role of autotrophs and heterotrophs
  different and the same?
• What are the human impacts on the cycle?

29
(No Transcript)
30
Implications for Human Societies

• Ecosystem sustainability
• Value of ecosystem capital
• The future

31
Ecosystem Sustainability

• Ecosystems use sunlight as their source of
  energy.
• Ecosystems dispose of wastes and replenish
  nutrients by recycling.

32
Nutrient Recycling and Energy Flow through an
Ecosystem
33
The Human System
34
The Human System
35
The Human System

• Excessive use of fossil fuels
• Feeding largely on the third trophic level
• Use of coal or nuclear power
• Use of agricultural land to produce meats

36
The Human System

• Lack of recycling
• Excessive use of fertilizers
• Destruction of tropical rain forests
• Nutrient overcharge into aquatic ecosystems
• Production and use of nonbiodegradable compounds

37
Value of Ecosystem Capital

• Gas regulation
• Climate regulation
• Disturbance regulation
• Water regulation and supply
• Erosion control and sediment retention
• Soil formation
• Nutrient recycling

38
Value of Ecosystem Capital

• Waste treatment
• Pollination
• Biological control
• Refugia
• Food production
• Raw materials
• Genetic resources

39
End of Chapter 3