Environmental ScienceEnvironmental Science Unit 2Unit 2

Abiotic and Biotic Parts of EcosystemsAbiotic and Biotic Parts of Ecosystems

Thanks to Dr. E – La Canada High School

Systems and FeedbackSystems and Feedback

System: A set of components or parts that function together to act

as a whole. Open System:

Not generally contained within boundaries Some energy or material moves into or out of the system

Closed System: No energy movement into or out of the system

Systems and FeedbackSystems and Feedback

Feedback Occurs when the output of the system also serves as an input,

leading to further changes in the system Negative Feedback

Occurs when the system’s response is in the opposite direction of the output

Self-regulating Positive Feedback

Occurs when an increase in output leads to a further increase in output

© 2008 John Wiley and Sons Publishers

© 2008 John Wiley and Sons Publishers

Exponential growth: Growth occurs at a constant rate per time period Equation to describe exponential growth is:

Doubling time The time necessary for the quantity being measured to

double. Approximately equal to 70 divided by the annual

percentage growth rate

Exponential GrowthExponential Growth

Environmental UnityEnvironmental Unity

Environmental unity: It is impossible to change only one thing;

everything affects everything else.

UniformitarianismUniformitarianism

Uniformitarianism: The principle that processes that operate today

operated in the past. Observations of processes today can explain

events that occurred in the past and leave evidence

“The present is the key to the past.”

Changes and Equilibrium in Systems Changes and Equilibrium in Systems

Steady state: A dynamic equilibrium Material or energy is entering and leaving the

system in equal amounts Opposing processes occur at equal rates

© 2008 John Wiley and Sons Publishers

Changes and Equilibrium in SystemsChanges and Equilibrium in Systems

Average residence time: The time it takes for a given part of the total

reservoir of a particular material to be cycled through the sytem

The equation for average residence time is:

ART = S/F

© 2008 John Wiley and Sons Publishers

Earth as a Living SystemEarth as a Living System

Biota: All the organisms of all species living in an area

or region up to and including the biosphere Biosphere:

1. That part of a planet where life exists

2. The planetary system that includes and sustains life

EcosystemEcosystem

Ecosystem: A community of organisms and its local nonliving

environment in which matter (chemical elements) cycles and energy flows.

Sustained life on Earth is a characteristic of ecosystems

Can be natural or artificial

EcosystemsEcosystems

The Gaia Hypothesis: Named for Gaia, the Greek goddess Mother Earth States that the surface environment of the Earth, with respect to

such factors as the atmospheric composition of gases acidity-alkalinity of waters Surface temperature

are actively regulated by the sensing, growth, metabolism and other activities of the biota.

Or, life manipulates life the environment for the maintenance of life.

Why Solving Environmental Problems Why Solving Environmental Problems Is Often DifficultIs Often Difficult

1. Exponential growth• The consequences of exponential growth and its

accompanying positive feedback can be dramatic2. Lag time

• The time between a stimulus and the response of a system

• If there is a long delay between stimulus and response, then the resulting changes are much more difficult to recognize.

3. Irreversible consequences• Consequences that may not be easily rectified on a

human scale of decades or a few hundred years.

© 2008 John Wiley and Sons Publishers

MatterMatterForms, Structure, and QualityForms, Structure, and Quality

Matter is anything that has mass and takes up space.

Matter is found in two chemical forms: elements and compounds.

Various elements, compounds, or both can be found together in mixtures.

Solid, Liquid, and GasSolid, Liquid, and Gas

Atoms, Ions, and MoleculesAtoms, Ions, and Molecules

Atoms: The smallest unit of matter that is unique to a particular element.

Ions: Electrically charged atoms or combinations of atoms.

Molecules: Combinations of two or more atoms of the same or different elements held together by chemical bonds.

What are Atoms?What are Atoms?

The main building blocks of an atom are positively charged PROTONS, uncharged NEUTRONS, and negatively charged ELECTRONS

Each atom has an extremely small center, or nucleus, containing protons and neutrons.

http://mediaserv.sus.mcgill.ca/content/2004-Winter/180-Winter/Nuclear/frame0008.htm

Atomic Number and Mass Atomic Number and Mass Number.Number.

Atomic number The number of protons in the

nucleus of each of its atoms. Mass number

The total number of protons and neutrons in its nucleus.

Elements are organized through the periodic table by classifications of metalsmetals, , metalloidsmetalloids,

and nonmetalsnonmetals

Inorganic CompoundsInorganic Compounds All compounds not Organic Ionic Compounds

sodium chloride (NaCl) sodium bicarbonate (NaOH)

Covalent compounds hydrogen(H2) carbon dioxide (CO2) nitrogen dioxide (NO2) sulfur dioxide (SO2) Ammonia (NH3)

Inorganic CompoundsInorganic Compounds

The earth’s crust is composed of mostly inorganic minerals and rock

The crust is the source of all most nonrenewable resource we use: fossil fuels, metallic minerals, etc.

Various combinations of only eight elements make up the bulk of most minerals.

Nonmetallic Elements.Nonmetallic Elements.

Carbon (C), Oxygen (O), Nitrogen (N), Sulfur (S), Hydrogen (H), and Phosphorous (P).

Nonmetallic elements make up about 99% of the atoms of all living things.

Ionic CompoundsIonic Compounds

Structure Composed of oppositely-charged ions Network of ions held together by attraction

Ionic bonds Forces of attraction between opposite charges

Formation of Ionic Compounds Transfer of electrons between the atoms of

these elements Atom that is metal loses electrons (oxidation) to

become positive Atom that is nonmetal gains electrons

(reduction) to become negative Results in drastic changes to the elements

involved

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/redox.gif

Sodium ChlorideSodium Chloride Sodium is a rather "soft" metal solid, with a

silver-grey color Chlorine is greenish colored gas When a single electron is transferred

between these elements, their atoms are transformed via a violent reaction into a totally different substance called, sodium chloride, commonly called table salt -- a white, crystalline, and brittle solid

Formed by two non-metals Similar electronegativities Neither atom is "strong" enough to steal

electrons from the other Therefore, the atoms must share the

electrons

Covalent Bonds

Covalent Bonds Chlorine atoms with valence electrons shown Chlorine atom has seven valence electrons, but

wants eight When unpaired electron is shared, both atoms now

have a full valence of eight electrons Individual atoms are independent, but once the

bond is formed, energy is released, and the new chlorine molecule (Cl2) behaves as a single particle

Organic CompoundsOrganic Compounds Compounds containing carbon atoms

combined with each other with atoms of one or more other elements such as hydrogen, oxygen, nitrogen, sulfur, etc. Hydrocarbons

Compounds of carbon and hydrogen Chlorofluorocarbons

Carbon, chlorine, and fluorine atoms Simple carbohydrates

carbon, hydrogen, oxygen combinations

Organic CompoundsOrganic Compounds

Hydrocarbons Chlorofluorocarbons

Biological Organic CompoundsBiological Organic Compounds

Carbohydrates (Glucose) Protein (Cytochrome P450)

Biological Organic CompoundsBiological Organic Compounds

Lipid (Triglyceride) Nucleic Acid (DNA)

Earth’s CrustEarth’s Crust

Matter QualityMatter Quality

Matter quality is a measure of how useful a matter resource is, based in its availability and concentration.

High quality matter is organized, concentrated, and usually found near the earth’s crust.

Low quality is disorganized, dilute, and has little potential for use as a matter resource.

High quality & Low qualityHigh quality & Low quality

HIGH QUALITY LOW QUALITY

Energy Energy

Energy is the capacity to do work and transfer heat.

Energy comes in many forms: light, heat, and electricity.

Kinetic energy is the energy that matter has because of its mass and its speed or velocity.

ElectElectroromagnemagnetic Stic Spectpectrurumm The range of electromagnetic waves, which differ in

wavelength (distance between successive peaks or troughs) and energy content.

Kinetic energy.Kinetic energy.

Kinetic energy is the energy that matter has because of its mass and its speed or velocity.

It is energy in action or motion. Wind, flowing streams, falling rocks,

electricity, moving car - all have kinetic energy.

Potential energyPotential energy

Potential energy is stored energy that is potential available for use.

Potential energy can be changed to kinetic energy.

Energy QualityEnergy Quality

Very High: Electricity, Nuclear fission, and Concentrated sunlight.

High: Hydrogen gas, Natural gas, and Coal. Moderate: Normal sunlight, and wood. Low: Low- temperature heat and dispersed

geothermal energy.

The “Law of Conservation of The “Law of Conservation of Matter and Energy”Matter and Energy”

In any nuclear change, the total amount of matter and energy involved remains the same.

E = mc2

The energy created by the release of the strong nuclear forces for 1 kilogram of matter will produce enough energy to elevate the temperature of all the water used in the Los Angeles basin in one day by 10,000oC

First Law of ThermodynamicsFirst Law of Thermodynamics

In all physical and chemical changes Energy is neither created nor destroyed But it may be converted from one form to

another

Second Law of ThermodynamicsSecond Law of Thermodynamics

When energy is changed from one form to another

Some of the useful energy is always degraded to lower-quality, more dispersed, less useful energy

Also known as Law of Entropy

High Waste SocietiesHigh Waste Societies

People continue to use and waste more and more energy and matter resources at an increasing rate

At some point, high-waste societies will become

UNSUSTAINABLE!UNSUSTAINABLE!

Goals of Matter Recycling SocietiesGoals of Matter Recycling Societies

To allow economic growth to continue To allow economic growth to continue without depleting matter resources or without depleting matter resources or

producing excess pollutionproducing excess pollution

Matter Recycling SocietiesMatter Recycling Societies

AdvantagesAdvantages Saves EnergySaves Energy Buys TimeBuys Time

DisadvantagesDisadvantages Requires high-quality energy Requires high-quality energy

which cannot be recycledwhich cannot be recycled Adds waste heatAdds waste heat No infinite supply of affordable No infinite supply of affordable

high-quality energy availablehigh-quality energy available Limit to number of times a Limit to number of times a

material can be recycledmaterial can be recycled

Low Waste SocietiesLow Waste Societies

Works with nature to reduce throughput Based on energy flow and matter recycling

Low Waste Societies FunctionLow Waste Societies Function

1. Reuse/recycle most nonrenewable matter resources

2. Use potentially renewable resources no faster than they are replenished

3. Use matter and energy resources efficiently

Low Waste Societies FunctionLow Waste Societies Function

4. Reduce unnecessary consumption

5. Emphasize pollution prevention and waste reduction

6. Control population growth

www.sws.uiuc.edu/nitro/biggraph.asp

GeosphereGeosphere

Lithosphere Crust and upper mantle

Crust Outermost, thin silicate zone, eight

elements make up 98.5% of the weight of the earth’s crust

The Earth contains several layers or concentric spheres

GeosphereGeosphere Mantle

Surrounded by a thick, solid zone, largest zone, rich with iron, silicon, oxygen, and magnesium, very hot

Core Innermost zone, mostly iron, solid

inner part, surrounded by a liquid core of molten material

Inner Core is hotter than surface of the Sun

Thin envelope of air around the planet Troposphere

extends about 17 kilometers above sea level, contains nitrogen (78%), oxygen(21%), and is where weather occurs

Stratosphere 17-48 kilometers above sea

level, lower portions contains enough ozone (O3) to filter out most of the sun’s ultraviolet radiation

AtmosphereAtmosphere

Consists of the earth’s liquid water, ice, and

water vapor in the atmosphere

HydrosphereHydrosphere

What Sustains What Sustains Life on Earth?Life on Earth?

Life on the earth depends on three interconnected factors One-way flow of high-quality energy

from the sun Cycling of matter or nutrients (all

atoms, ions, or molecules needed for survival by living organisms), through all parts of the ecosphere

Gravity, which allows the planet to hold onto its atmosphere and causes the downward movement of chemicals in the matter cycles

SunSun

Fireball of hydrogen (72%) and helium (28%)

Nuclear fusion Sun has existed for 6 billion years Sun will stay for another 6.5 billion years Visible light that reaches troposphere is

the ultraviolet ray which is not absorbed in ozone

Solar EnergySolar Energy

72% of solar energy warms the lands 0.023% of solar energy is captured by green

plants and bacteria Powers the cycling of matter and weather

system Distributes heat and fresh water

www.bom.gov.au/lam/climate/levelthree/ climch/clichgr1.htm

Type of NutrientsType of Nutrients

Nutrient Any atom, ion, or molecule an organism needs to live grow

or reproduce Ex: carbon, oxygen, hydrogen, nitrogen… etc

Macronutrient nutrient that organisms need in large amount Ex: phosphorus, sulfur, calcium, iron … etc

Micronutrient nutrient that organism need in small amount Ex: zinc, sodium, copper… etc

Limiting FactorLimiting Factor

More important than others in regulating population growth Ex: water light, and soil Lacking water in the desert can limit the growth of

plants

Limiting Factor PrincipleLimiting Factor Principle

too much or too little of any abiotic factor can limit growth of population, even if all the other factors are at optimum (favorable) range of tolerance. Ex: If a farmer plants corn in phosphorus-poor

soil, even if water, nitrogen are in a optimum levels, corn will stop growing, after it uses up available phosphorus.

Living Organisms in EcosystemLiving Organisms in Ecosystem

Producers or autotrophs- makes their own food from compound obtained from environment.

Ex: plant gets energy or food from sun

Living Organisms in EcosystemLiving Organisms in Ecosystem

Photosynthesis- ability of producer to convert Photosynthesis- ability of producer to convert sunlight, abiotic nutrients to sugars and other sunlight, abiotic nutrients to sugars and other complex organic compoundscomplex organic compounds

Chlorophyll- traps solar energy and converts into Chlorophyll- traps solar energy and converts into chemical energychemical energy

Producer transmit 1-5% of absorbed energy into chemical energy, which is stored in complex carbohydrates, lipids, proteins and nucleic acid in plant tissue

Chemosynthesis-Chemosynthesis- Bacteria can convert simple

compounds from their environment into more complex nutrient compound without sunlight Ex: becomes consumed by

tubeworms, clams, crabs Bacteria can survive in great

amount of heat

RespirationRespiration

Aerobic Respiration Uses oxygen to convert organic nutrients back into

carbon dioxide and water Glucose + oxygen Carbon dioxide + water +

energy Anaerobic Respiration or Fermentation

Breakdown of glucose in absence of oxygen

Second Law of EnergySecond Law of Energy

Organisms need high quality chemical energy to move, grow and reproduce, and this energy is converted into low-quality heat that flows into environment Trophic levels or feeding levels- Producer is a

first trophic level, primary consumer is second trophic level, secondary consumer is third.

Decomposers process detritus from all trophic levels.

Chapter 5Chapter 5

Nutrient Cycles and Soils

Matter Cycling in EcosystemsMatter Cycling in Ecosystems

Nutrient or Biogeochemical Cycles Natural processes that recycle

nutrients in various chemical forms in a cyclic manner from the nonliving environment to living organisms and back again

Nutrient Cycles (Closed System) Nutrient Cycles (Closed System) Energy Flow (Open System)Energy Flow (Open System)

WaterCarbonNitrogenPhosphorus

SulfurRockSoilEnergy Flow

Biogeochemical Cycle LocationsBiogeochemical Cycle Locations

Hydrosphere Water in the form of ice, liquid, and vapor Operates local, regional, and global levels

Atmospheric Large portion of a given element (i.e. Nitrogen gas) exists in

gaseous form in the atmosphere Operates local, regional, and global levels

Sedimentary The element does not have a gaseous phase or its gaseous

compounds don’t make up a significant portion of its supply Operates local and regional basis

Nutrient Cycling & Ecosystem Nutrient Cycling & Ecosystem Sustainability Sustainability

Natural ecosystems tend to balance Nutrients are recycled with reasonable efficiency

Humans are accelerating rates of flow of mater Nutrient loss from soils Doubling of normal flow of nitrogen in the nitrogen

cycle is a contributes to global warming, ozone depletion, air pollution, and loss of biodiversity

Isolated ecosystems are being influenced by human activities