Ecosystems and Energy Chapter 3
Dec 17, 2015
Ecosystems and Energy
Chapter 3
What is Ecology?
Ecology –
study of the interactions among organisms and between organisms (biotic) and their abiotic environment.
Levels of Biological Organization
What is Ecology?
Ecological Levels of Organization:
Population
What is Ecology?
Ecological Levels of Organization:
Community
What is Ecology?
Ecological Levels of Organization:
Ecosystem
CO2
What is Ecology?
Landscape –
encompasses larger area and several ecosystems
Biosphere –
the whole earth
“Between 50 and 100 million years ago, during the Cretaceous and Tertiary geological periods , the Atlantic Ocean covered much of Georgia south of an imaginary line drawn from Columbus to Augusta, which is where the Piedmont Plateau meets the coastal plain. Above this line, known as the Fall Line, weathered crystalline rocks at the Piedmont Plateau began to break down and rushing streams carried the tiny feldspar and kaolinite crystals seaward to form large sedimentary deposits. During later periods, earth was piled on top of the kaolin; this overlying layer of earth contained sharks’ teeth, sand dollars and other marine life fossils and contributed to the alteration of the feldspar and kaolinite deposits”
Georgia’s Fall Line
http://www.kaolin.com/geology/
The Energy of Life
Potential vs. Kinetic Energy
The Energy of Life
Thermodynamics –
The Energy of Life
1st Law of Thermodynamics –
energy can change forms, but is not created or destroyed
2nd Law of Thermodynamics –
“Entropy Rules!”
amount of usable energy decreases as energy changes forms
1st Law deals with quantity of energy,
2nd Law with quality of energy.
The Energy of Life
Photosynthesis
6 CO2 + 12 H2O + radiant energy
C6H12O6 + 6 H2O + 6 O2
The Energy of Life
Cellular Respiration
C6H12O6 + 6 O2 + 6 H2O
6 CO2 + 12 H2O + energy
Physical and chemical factors limit primary production in ecosystems
• The amount of light energy converted to chemical energy by an ecosystem’s autotrophs in a given time period is called primary production.
• In aquatic ecosystems, light and nutrients limit primary production.
• In terrestrial ecosystems, temperature, moisture, and nutrients limit primary production.
• The Global Energy Budget
– Every day, Earth is bombarded by large amounts of solar radiation.• Much of this radiation lands on water and land
that either reflect or absorb it.• Of the visible light that reaches photosynthetic
organisms, only about 1% is converted to chemical energy.– Although this is a small amount, primary
producers are capable of producing about 170 billion tons of organic material per year.
• Gross and Net Primary Production
• – Total primary production is known as gross primary
production (GPP).• This is the amount of light energy that is converted into
chemical energy.
– The net primary production (NPP) is equal to gross primary production minus the energy used by the primary producers for respiration (R):• NPP = GPP –R
Why is the Ocean Blue?
– Nitrogen is the one nutrient that limits phytoplankton growth in many parts of the ocean.
– Nutrient enrichment experiments show that iron availability also limits primary production.
• Iron stimulation is related to the nitrogen stimulation.
• When iron is added cyanobacteria populations increase
• Cyanobacteria can fix inorganic N2 into organic nitrogen that will “fertilize” phytoplankton
The Energy of Life
Case-in-Point: Life Without the Sun
IS ALL PRIMARY PRODUCTIVITY
PHOTOSYNTHETIC?
The Flow of Energy Through Ecosystems
Producers, Consumers, and Decomposers
The Path of Energy Flow
Food Chains –
Food Webs –
The Path of Energy Flow
Case-in-Point: How Humans Have Affected the Antarctic Food Web
Krill
Baleen whales
Squid Fishes
Toothed whalesSealsPenguins
What would happen if you eliminated krill?
The Path of Energy Flow
Ecological Pyramids
Pyramid of Numbers Pyramid of Biomass
The Path of Energy Flow
Ecological Pyramids
Pyramid of Energy
The Path of Energy Flow
Example: Thermodynamics in Action
Desert: Primary producers = 100 g / m2
Temperate forest: Primary producers = 1,500 g / m2
Food webs very simple, very few tertiary consumers
Food webs very complex, more tertiary consumers, some quaternary.
The Path of Energy Flow
Desert Biomass Pyramid
Primary producers = 100 g / m2
Primary consumers = 10 g / m2
Secondary consumers = 1.0 g / m2
Tertiary consumers = 0.1 g / m2
Tertiary consumers must range over large areas to obtain enough energy to subsist.
such as . . .13.5 kg coyote must range ~12 ha to subsist (30 acres).
The Path of Energy Flow
Temperate Forest Biomass Pyramid
Primary producers = 1,500 g / m2
Primary consumers = 150 g / m2
Secondary consumers = 15 g / m2
Tertiary consumers = 1.5 g / m2
13.5 kg coyote only needs ~1 ha to subsist (2.5 acres).
Also, possibility of quaternary consumers, like bears.
NOTE: just relative examples, not accurate