Ecosystems and Energy

Chapter 3

Chapter 3 Primary Themes

1.Distinguish ecological levels2.Define and explain energy3.Laws of thermodynamics4.Reactions for photosynthesis & respiration5.Explain pyramids & webs in terms of energy,

biomass, and relationships6.Describe life in terms of GDP and NPP

What is Ecology?

Ecology –

study of the interactions among organisms (biotic) and their abiotic environment.

Level of organization – Ecology in a System: Ecosystem

Spheres of Organization

Landscape Ecology –

encompasses larger area and several ecosystems

Biosphere –

the whole earth

Energy Drives Life

What types of energy are there?

The Energy of Life

Potential vs. Kinetic Energy

All energy forms summed into two forms

Types of Energy1. Chemical - energy stored in bonds2. Radiant - wave energy: electromagnetic3. Thermal - energy flow from high heat to low4. Mechanical - the energy of motion5. Nuclear - atomic nuclei6. Electrical - flow of charged particles

The Energy of LifeThermodynamics – the study of energy

and its transformations.

The Energy of Life1st 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

The Energy of Life

Case-in-Point: Life Without the Sun

Hydrothermal Vents or Black Smokers • Chemosynthesis• Tube Worms

See You Tube - black smokers

Chemosynthesis

An extremophile is any microbe that thrives in extreme conditions of temperature, pressure, salinity, or concentrations of hostile chemicals.

Extremophiles commonly belong to the kingdom Archaebacteria.

Hydrogen sulfide chemosynthesis 6{CO2}+6{H2O}+3{H2S} → C6H12O6+3{H2SO4}

The Flow of Energy Through Ecosystems

Producers, Consumers, and Decomposers

The Path of Energy Flow

Food Chains –

Food Webs –

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.

Primary Production

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).

Primary Production

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

The Path of Energy Flow

Ecosystem Productivity

Net Primary Productivity

Gross Primary Productivity

Plant cellular respiration=

The Path of Energy Flow

Ecosystem Productivity