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Systems on Earth
• System: – A group of interacting,
interrelated, or interdependent elements forming a complex whole.
• Synergy:– The interaction of two or
more agents or forces so that their combined effect is greater than the sum of their individual effects.
System > Sum of its Parts
• Cells• Tissues• Organs• Organ Systems• Individuals• Populations• Communities• Ecosystems
Systems on Earth
The Gaia Hypothesis
• James Lovelock– Independent scientist– Earth made of different
functioning units that interact with each other
– Changed focus of environmental movement
Systems
• All systems have– Inputs– Outputs– Processes
Types of Systems
• Open• Closed• Isolated
Open System
• Exchange of matter and energy
Closed System
• Exchange of energy only.
Isolated System
• No exchange of energy or matter• Do not exist naturally• Possibly the universe?
Energy
• Energy in all types of systems follows the laws of thermodynamics.
• Energy is released in the form of light and heat.
• Energy can be “stored” in the bonds or organic molecules.
1st Law of Thermodynamics
• Law of Conservation of Energy• Energy can neither be created nor destroyed.• Energy can only change forms.• Cells cannot produce energy – they burn sugars to
produce ATP (respiration).• Plant cells convert the sun’s energy to sugar, which they burn for energy.
2nd Law of Thermodynamics
• Energy flows from high quality to low quality.• Energy is lost during every conversion
between forms• Energy = Work + Heat• As systems lose energy they become more
disorganized – more entropy• The sun supplies constant, high quality energy
Life and the 2nd Law
• Life is a struggle against entropy.• Organization takes energy!
ENERGYis the foundationof all ecosystems
Equilibrium
• Ecosystems are open systems• Open systems tend to exist in a state of
balance, or equilibrium– Static equilibrium• Components of the system stay unchanged• Ex: makeup of Earth’s crust
– Dynamic equilibrium• The system is unstable on the short term• Stays unchanged over the long term
Regulation of Systems
• Systems are managed by feedback loops• Positive feedback system– Cause change in the same direction as the system
Regulation of Systems
• Negative feedback systems– Cause change in the opposite direction from the
original system– Like a furnace/ thermostat in your house
Processes Within Ecosystems
• Both materials and energy move through ecosystems– Materials can be recycled– Energy cannot
Two Types of Processes
• Transfers– Require little energy– Change in location of material or energy– Examples• Movement of materials when one organism eats
another• Movement of water through runoff• Heat energy moving in ocean currents, air masses
Two Types of Processes
• Transformations– Change in form of the energy or materials– Requires more energy– Examples:• Conversion of energy from glucose to ATP during
respiration• Conversion of sun’s energy from light to organic
molecules during photosynthesis• Evaporation or condensation of water• Burning of fossil fuels
Diagramming Systems
• Storage– Parts of a system where energy or materials
accumulate– Drawn as a box (think engine in a box)
• Flows– Inputs – movement into the storage– Outputs – movement out of the storage– Can be transfers or transformations
Diagramming Systems
StorageINPUT OUTPUT
Systems Diagram: Energy in an Ecosystem
