Environmental Science: Toward a Sustainable Future Richard T. Wright Ecosystems: How They Work PPT by Clark E. Adams Chapter 3

Ecosystems Function: Transfer Energy and Nutrients Matter, energy, and life Energy flow in ecosystems The cycling of matter in ecosystems Implications for human societies

Matter, Energy, and Life Matter in living and nonliving systems Energy basics Energy changes in organisms

Environmental Spheres

Elements of Life Organic = carbon-based molecules Examples: C 6 H 12 O 6, CH 4 Inorganic = molecules without carbon–carbon or carbon–hydrogen bonds Examples: NaCl, NH 4, H 2 SO 4

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?

78% Nitrogen 21% Oxygen < 0.04% Carbon Dioxide Atmospheric Gases

Match the Elements (Left) with Molecules (Right) Nitrogen Carbon Hydrogen Oxygen Phosphorus Sulfur Glucose Proteins Starch Fats Nucleic acids All of the above

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

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

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 CAN’T BREAK EVEN!

Entropy: Energy Changes in Organisms Systems will go spontaneously in one direction only, which is toward increasing entropy..

Example of the Laws of Conservation of Matter and Thermodynamics Global Warming Acid Rain Smog Burning Coal = CO 2 + SO + H Ash + (C x H x S x O x ) Light + Noise + Heat

Ecosystems Use Sunlight As Their Source of Energy

Conservation of Matter and Energy Capture Photosynthesis 6 CO H 2 0 C 6 H 12 O O 2 Respiration C 6 H 12 O O 2 6 CO H 2 0

Food Assimilation in Consumers

Match Outcomes (Left) with Process (Right) Releases O 2 Stores energy Releases CO 2 Uses CO 2 Releases energy Produces sugar Uses sugar Uses O 2 Photosynthesis Cell respiration Both Neither

Match Outcomes (Left) with Organisms (Right) Releases O 2 Stores energy Releases CO 2 Uses CO 2 Releases energy Produces sugar Uses sugar Uses O 2 Plants Animals Both Neither

Energy Flow in Ecosystems Primary production Energy flow and efficiency Running on solar energy  Freely available  Nonpolluting  Everlasting

Productivity of Different Ecosystems

Energy Flow through Trophic Levels Producer 10,000 Kcal Third-order Consumer Secondary Consumer Primary Consumer - 100x - 10x 100 Kcal 10 Kcal 1 Kcal

Energy Flow through Trophic Levels

The Cycling of Matter in Ecosystems The carbon cycle The phosphorus cycle The nitrogen cycle

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?

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?

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?

Implications for Human Societies Ecosystem sustainability Value of ecosystem capital The future

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

Nutrient Recycling and Energy Flow through an Ecosystem

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

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

Value of Ecosystem Capital Gas regulation Climate regulation Disturbance regulation Water regulation and supply Erosion control and sediment retention Soil formation Nutrient recycling

Value of Ecosystem Capital Waste treatment Pollination Biological control Refugia Food production Raw materials Genetic resources

End of Chapter 3