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 CO 2

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

The Energy of Life Potential vs. Kinetic Energy

The Energy of Life Thermodynamics –

The Energy of Life 1 st Law of Thermodynamics – energy can change forms, but is not created or destroyed 2 nd Law of Thermodynamics – “Entropy Rules!” amount of usable energy decreases as energy changes forms 1 st Law deals with quantity of energy, 2 nd Law with quality of energy.

The Energy of Life Photosynthesis 6 CO H 2 O + radiant energy C 6 H 12 O H 2 O + 6 O 2

The Energy of Life Cellular Respiration C 6 H 12 O O H 2 O 6 CO H 2 O + 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 whales Seals Penguins 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 / m 2 Temperate forest: Primary producers = 1,500 g / m 2 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 / m 2 Primary consumers = 10 g / m 2 Secondary consumers = 1.0 g / m 2 Tertiary consumers = 0.1 g / m 2 Tertiary consumers must range over large areas to obtain enough energy to subsist. such as kg coyote must range ~12 ha to subsist (30 acres).

The Path of Energy Flow Temperate Forest Biomass Pyramid Primary producers = 1,500 g / m 2 Primary consumers = 150 g / m 2 Secondary consumers = 15 g / m 2 Tertiary consumers = 1.5 g / m kg coyote only needs ~1 ha to subsist (2.5 acres). Also, possibility of quaternary consumers, like bears. NOTE: just relative examples, not accurate