How do ecosystems function?E

nerg

y Fl

ows

Nut

rient

s C

ycle

= energy= mass + energy= mass (nutrients)

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.

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, Some energy is lost from the system as heat;

you will end up with less usable energy than you started with. New usable energy must

continuously be placed into the system. YOU CAN ‘T BREAK EVEN!

+ Heat Energy

+ Heat Energy

Reactions go spontaneously to randomness (Entropy).

Energy inputs are needed to maintain organization!

First Principle of Ecosystem Sustainability

• Most ecosystems capture sunlight as their source of energy during photosynthesis.

• Nonpolluting and nondepletable.

• There are unique ecosystems at ocean floor hydrothermal vents that use geothermal energy as a source of energy.

The Second Principle of Ecosystem Sustainability

• Ecosystems dispose of wastes and replenish nutrients by recycling all elements.

• This involves release of inorganic minerals from organic matter; mostly due to respiration by microbial decomposers.

Solar energy converts to chemical energy and heat during photosynthesis

Which process uses and which produces energy?

Which process occur in plants and which in animals?

Photosynthesis 6 CO2 + 6 H20 C6H12O6 + 6 O2

Respiration C6H12O6 + 6 O2 6 CO2 + 6 H20

Consumers lose much of their ingested energy (i.e. diet) due to cellular respiration and excretion. Only a small portion (about 10%) gets assimilated into tissues.

Match Outcomes (Left) With Process (Right)

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

Match Outcomes (Left) With Organisms (Right)

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

C Cycle

N Cycle

The Human SystemThe Human System

Violations of the First Principle of Ecosystem Sustainability

• Excessive use of fossil fuels.

• Use of nuclear power or other.

• Feeding largely at the third trophic level.

• Use of agricultural land to produce meats.

Most ecosystems capture sunlight as their source of energy by photosynthesis.

Violations of the Second Principle of Ecosystem Sustainability

• Lack of recycling.• Excessive use of fertilizers.• Destruction of tropical rain forests.• Nutrient overcharge into aquatic

ecosystems.• Production and use of non-biodegradable

compounds.

Ecosystems dispose of wastes and replenish nutrients by recycling all elements.

Ecosystem Services and Functions

* Gas, climate and water regulation* Gas, climate and water regulation* Water supply* Water supply* Erosion control* Erosion control* Soil formation* Soil formation* Pollination control* Pollination control* Biological control* Biological control

* Food production* Food production* Recreation* Recreation* Raw materials* Raw materials* Nutrient cycling* Nutrient cycling* Waste treatment* Waste treatment