Science, Matter, Energy and Ecosystems

Matter and Energy

•Read section 2-2 on Matter and Energy

•Background to many ES issues and future chapters

•We will discuss some but not all

Science and Critical Thinking

•Scientific method

•Scientific hypotheses

•Scientific theories

•Scientific (natural) laws

•Peer review and publication

•Frontier science

•Junk Science



Organic Compounds

•organic compounds

–Compounds containing carbon atoms combined with each other and with atoms of one or more other elements such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, chlorine, and fluorine.

•inorganic compounds

–All compounds not classified as organic compounds.

The Law of Conservation of Matter

•Matter is not destroyed

•It only changes form

•There is no “away”


First Law of Thermodynamics

•Energy is neither created nor destroyed

•Energy only changes form

•You can’t get something for nothing





Second Law of Thermodynamics

•In every transformation, some energy is converted to heat

•You cannot break even in terms of energy quality




•Photosynthesis is the process of converting solar energy into chemical energy stored in food

•CO2 + H20 ---> C6H12O6 + O2



•Respiration is the process of releasing chemical energy stored in food to be used by living things.

•C6H12O6 + O2 --->  CO2 + H20

Ecological Concepts

•Ecology: Study of how organisms interact with each other and with their non-living surroundings.

•Eco - is from the Greek word “Oikos” for house

The Nature of Ecology

Levels of study in Ecology:







The Earth’s Life-Support Systems







Natural Capital: Sustaining Life of Earth

•One-way flow
of energy from Sun

•Cycling of
crucial elements



Solar Capital: Flow of Energy to and from the Earth

Ecosystem Components

•Abiotic factors

•Biotic factors

•Range of tolerance for each species

–what factors are important for…


Ecosystem Components

•Limiting factors determines distributions


Common limiting factors

•Terrestrial ecosystems (on land)



–soil nutrients

•Aquatic ecosystems




–dissolved oxygen


Biological Components of Ecosystems

•Producers (autotrophs)

•Consumers (heterotrophs)

–Herbivores, carnivores, omnivores

–Decomposers and detritivores

•detritus = dead organic material



•Genetic diversity

•Species diversity

•Ecological diversity

•Functional diversity

Energy Flow in Ecosystems

•Food chains

•Food webs

•Trophic levels

–each step in the flow of energy through an ecosystem (feeding level)

Food Chains and Energy Flow in Ecosystems

Ecological Pyramids

•Pyramid of energy flow

•Ecological efficiency

•Pyramid of biomass

•Pyramid of numbers

Food webs

•reality tends to be more complex than a linear food chain

Primary Productivity of Ecosystems

•Gross primary productivity (GPP)

•The rate at which an ecosystem's producers capture and store a given amount of chemical energy as biomass in a given length of time.

•Net primary productivity (NPP)

•Rate at which all the plants in an ecosystem produce net useful chemical energy; equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (gross primary productivity) and the rate at which they use some of that energy through cellular respiration.


Net Primary Productivity comparison




•Maturity and Horizons

•Variations with Climate and Biomes

•Variations in Texture and Porosity

Soil Profiles in Different Biomes

Matter Cycling in Ecosystems

Biogeochemical cycles

•Hydrologic cycle (H2O)

•Carbon cycle

• Nitrogen cycle

•Phosphorus cycle


Hydrologic (Water) Cycle

The Carbon Cycle (Marine)

The Carbon Cycle (Terrestrial)

The Nitrogen Cycle

The Phosphorus Cycle