ch 3: ecosystems – what are they and how do they work?
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Ch 3: Ecosystems – What Are They and How Do They Work?. Core Case Study: Tropical Rain Forests Are Disappearing. Cover about 2% of the earth’s land surface Contain about 50% of the world’s known plant and animal species Disruption will have three major harmful effects Reduce biodiversity - PowerPoint PPT PresentationTRANSCRIPT
Core Case Study: Tropical Rain Forests Core Case Study: Tropical Rain Forests Are DisappearingAre Disappearing
• Cover about 2% of the earth’s land surfaceCover about 2% of the earth’s land surface• Contain about 50% of the world’s known plant and Contain about 50% of the world’s known plant and
animal speciesanimal species• Disruption will have three major harmful effectsDisruption will have three major harmful effects
• Reduce biodiversityReduce biodiversity• Accelerate global warmingAccelerate global warming• Change regional weather patternsChange regional weather patterns
Natural Capital Degradation: Satellite Natural Capital Degradation: Satellite Image of the Loss of Tropical Rain ForestImage of the Loss of Tropical Rain Forest
3-1 What Is Ecology?3-1 What Is Ecology?
• Concept 3-1 Ecology is the study of how organisms interact with one another and with their physical environment of matter and energy.
Cells Are the Basic Units of LifeCells Are the Basic Units of Life
• Cell TheoryCell Theory• Eukaryotic cellEukaryotic cell• Prokaryotic cellProkaryotic cell
Fig. 3-2, p. 52
Stepped Art
Cell membrane
(a) Eukaryotic Cell(a) Eukaryotic Cell
Nucleus(DNA)
Proteinconstruction
Energyconversion
Protein construction and energyconversion occur without specializedinternal structures
(b) Prokaryotic Cell
DNA (no nucleus)
Cell membrane
Structure of a Eukaryotic Call and a Structure of a Eukaryotic Call and a Prokaryotic CellProkaryotic Cell
Species Make Up the Encyclopedia of Species Make Up the Encyclopedia of LifeLife
• SpeciesSpecies• 1.75 Million species identified1.75 Million species identified• Insects and other arthropods make up most of the Insects and other arthropods make up most of the
known speciesknown species• Perhaps 10–14 million species not yet identifiedPerhaps 10–14 million species not yet identified
Ecologists Study Connections in Ecologists Study Connections in NatureNature• Ecology Ecology • Levels of organizationLevels of organization
• PopulationPopulation• Genetic diversityGenetic diversity
• CommunityCommunity• EcosystemEcosystem• Biosphere Biosphere
Fig. 3-3, p. 52
Stepped Art
Smallest unit of a chemical element that exhibits its chemical propertiesAtom
Molecule Chemical combination of two or more atoms of the same or different elements
CellThe fundamental structural and functional unit of life
Organism An individual living being
Population A group of individuals of the same species living in a particular place
Community Populations of different species living in a particular place, and potentially interacting with each other
Ecosystem A community of different species interacting with one another and with theirnonliving environment of matter and energy
Parts of the earth's air, water, and soil where life is found
Biosphere
Ecology
Science Focus: Have You Thanked Science Focus: Have You Thanked the Insects Today?the Insects Today?
• PollinatorsPollinators• Eat other insectsEat other insects• Loosen and renew soilLoosen and renew soil• Reproduce rapidly Reproduce rapidly • Very resistant to extinctionVery resistant to extinction
3-2 What Keeps Us and Other 3-2 What Keeps Us and Other Organisms Alive?Organisms Alive?• Concept 3-2 Life is sustained by the flow of energy
from the sun through the biosphere, the cycling of nutrients within the biosphere, and gravity.
The Earth’s Life-Support System Has The Earth’s Life-Support System Has Four Major ComponentsFour Major Components
• AtmosphereAtmosphere• TroposphereTroposphere• StratosphereStratosphere
• HydrosphereHydrosphere• GeosphereGeosphere• BiosphereBiosphere
Fig. 3-6, p. 55
Rock
AtmosphereVegetationand animals
Lithosphere
Biosphere
Mantle
Crust
Soil
Biosphere(living organisms)
Geosphere(crust, mantle, core)
Mantle
Core
Hydrosphere(water)
Crust(soil and rock)
Atmosphere(air)
Natural Natural Capital: Capital: General General
Structure Structure of the of the EarthEarth
Life Exists on Land and in WaterLife Exists on Land and in Water
• BiomesBiomes• Aquatic life zonesAquatic life zones
• Freshwater life zonesFreshwater life zones• Lakes and streamsLakes and streams
• Marine life zonesMarine life zones• Coral reefsCoral reefs• EstuariesEstuaries• Deep oceanDeep ocean
Fig. 3-7, p. 55
Average annual precipitation
100–125 cm (40–50 in.)75–100 cm (30–40 in.)50–75 cm (20–30 in.)25–50 cm (10–20 in.)below 25 cm (0–10 in.)
AppalachianMountains
Coastal mountainranges
Sierra Nevada
Great American
Desert
RockyMountains
GreatPlains
MississippiRiver Valley
Deciduous forestCoastal chaparraland scrub
Coniferous forest Desert Coniferous forest Prairie grassland
San Francisco
BaltimoreDenver
St. Louis
Major Biomes along the 39th Parallel in the U.S.
Three Factors Sustain Life on EarthThree Factors Sustain Life on Earth
• One-way flow of high-quality energy beginning with One-way flow of high-quality energy beginning with the sunthe sun
• Cycling of matter or nutrientsCycling of matter or nutrients
• GravityGravity
What Happens to Solar Energy What Happens to Solar Energy Reaching the Earth?Reaching the Earth?
• UV, visible, and IR energyUV, visible, and IR energy• Radiation Radiation
• Absorbed by ozoneAbsorbed by ozone• Absorbed by the earthAbsorbed by the earth• Reflected by the earthReflected by the earth• Radiated by the atmosphere as heatRadiated by the atmosphere as heat
• Natural greenhouse effectNatural greenhouse effect
Fig. 3-8, p. 56
Lower Stratosphere(ozone layer)
Solarradiation
UV radiation
Visiblelight Heat radiated
by the earth
Mostabsorbedby ozone
Absorbedby the earth
Greenhouseeffect
Reflected byatmosphere Radiated by
atmosphereas heat
Heat
Troposphere
Flow of Energy to and from the Earth
3-3 What Are the Major Components 3-3 What Are the Major Components of an Ecosystem?of an Ecosystem?
• Concept 3-3A Ecosystems contain living (biotic) and nonliving (abiotic) components.
• Concept 3-3B Some organisms produce the nutrients they need, others get their nutrients by consuming other organisms, and some recycle nutrients back to producers by decomposing the wastes and remains of organisms.
Ecosystems Have Living and Ecosystems Have Living and Nonliving ComponentsNonliving Components
• AbioticAbiotic• WaterWater• AirAir• NutrientsNutrients• RocksRocks• HeatHeat• Solar energy Solar energy
• BioticBiotic• Living and once livingLiving and once living
Fig. 3-9, p. 57
Decomposers
PrecipitationOxygen (O2)
Carbon dioxide (CO2)
Producer
Primaryconsumer(rabbit)
Secondaryconsumer(fox)
Producers
Water
Soluble mineralnutrients
Major Biotic and
Abiotic Parts of an
Ecosystem
Fig. 3-10, p. 58
Feworganisms
Feworganisms
Noorganisms
Noorganisms
Lower limitof tolerance
Higher limitof tolerance
Abundance of organisms
Zone ofintolerance
Zone ofphysiological
stress
Optimum range
Temperature
Zone ofintolerance
Zone ofphysiological
stress
Low High
Po
pu
lati
on
siz
eRange of Tolerance for a Population of Organisms
Several Abiotic Factors Can Limit Several Abiotic Factors Can Limit Population GrowthPopulation Growth
• Limiting factor principleLimiting factor principle• Too much or too little of any abiotic factor can Too much or too little of any abiotic factor can
limit or prevent growth of a population, even if all limit or prevent growth of a population, even if all other factors are at or near the optimal range of other factors are at or near the optimal range of tolerancetolerance
Producers and Consumers Are the Producers and Consumers Are the Living Components of Ecosystems Living Components of Ecosystems
• Producers, autotrophsProducers, autotrophs• PhotosynthesisPhotosynthesis• ChemosynthesisChemosynthesis
• Consumers, heterotrophsConsumers, heterotrophs• PrimaryPrimary• SecondarySecondary• Third and higher levelThird and higher level
• DecomposersDecomposers
Producers and Consumers Are the Producers and Consumers Are the Living Components of Ecosystems Living Components of Ecosystems
• DetritivoresDetritivores• Aerobic respirationAerobic respiration• Anaerobic respiration, fermentationAnaerobic respiration, fermentation
Fig. 3-11, p. 60
Mushroom
Detritus feeders Decomposers
Long-hornedbeetle holes
Time progression Powder broken down bydecomposers into plantnutrients in soil
Bark beetleengraving
Carpenterant galleries Termite and
carpenterant work Dry rot
fungus
Woodreducedto powder
Energy Flow and Nutrient Cycling Energy Flow and Nutrient Cycling Sustain Ecosystems and the BiosphereSustain Ecosystems and the Biosphere
• One-way energy flowOne-way energy flow• Nutrient cycling of key materialsNutrient cycling of key materials
Many of the World’s Most Important Many of the World’s Most Important Species Are Invisible to UsSpecies Are Invisible to Us
• MicroorganismsMicroorganisms• BacteriaBacteria• ProtozoaProtozoa• FungiFungi
3-4 What Happens to Energy in 3-4 What Happens to Energy in an Ecosystem?an Ecosystem?
• Concept 3-4A Energy flows through ecosystems in food chains and webs.
• Concept 3-4B As energy flows through ecosystems in food chains and webs, the amount of chemical energy available to organisms at each succeeding feeding level decreases.
Energy Flows Through Ecosystems in Energy Flows Through Ecosystems in Food Chains and Food WebsFood Chains and Food Webs
• Food chainFood chain• Food webFood web
Fig. 3-13, p. 62
Heat Heat
Heat
Heat Heat
Heat
Heat
Solarenergy
Tertiaryconsumers
(top carnivores)
First TrophicLevel
Second TrophicLevel
Third TrophicLevel
Fourth TrophicLevel
Producers(plants)
Primaryconsumers(herbivores)
Secondaryconsumers(carnivores)
Decomposers and detritus feeders
Fig. 3-14, p. 63
Squid
Fish
Herbivorouszooplankton
Krill
Sperm whale
Petrel
Adeliepenguin
Emperorpenguin
Leopardseal
Crabeaterseal
Blue whale
Elephantseal
Killerwhale
Phytoplankton
Carnivorousplankton
Humans
Usable Energy Decreases with Each Usable Energy Decreases with Each Link in a Food Chain or WebLink in a Food Chain or Web
• BiomassBiomass• Ecological efficiencyEcological efficiency• Pyramid of energy flowPyramid of energy flow• Food chain/pyramid song
Some Ecosystems Produce Plant Some Ecosystems Produce Plant Matter Faster Than Others DoMatter Faster Than Others Do
• Gross primary productivity (GPP)Gross primary productivity (GPP)• Net primary productivity (NPP)Net primary productivity (NPP)
• Ecosystems and life zones differ in their NPPEcosystems and life zones differ in their NPP
3-5 What Happens to Matter in 3-5 What Happens to Matter in an Ecosystem?an Ecosystem?
• Concept 3-5 Matter, in the form of nutrients, cycles within and among ecosystems and the biosphere, and human activities are altering these chemical cycles.
Nutrients Cycle in the BiosphereNutrients Cycle in the Biosphere
• Biogeochemical cycles, nutrient cyclesBiogeochemical cycles, nutrient cycles• HydrologicHydrologic• CarbonCarbon• NitrogenNitrogen• PhosphorusPhosphorus• Sulfur Sulfur
• Connect past, present , and future forms of lifeConnect past, present , and future forms of life
Water Cycles through the BiosphereWater Cycles through the Biosphere
• Natural renewal of water quality: three major processesNatural renewal of water quality: three major processes• EvaporationEvaporation• PrecipitationPrecipitation• TranspirationTranspiration
• Alteration of the hydrologic cycle by humansAlteration of the hydrologic cycle by humans• Withdrawal of large amounts of freshwater at rates faster Withdrawal of large amounts of freshwater at rates faster
than nature can replace itthan nature can replace it• Clearing vegetationClearing vegetation• Increased flooding when wetlands are drainedIncreased flooding when wetlands are drained
Science Focus: Water’s Unique Science Focus: Water’s Unique PropertiesProperties• Properties of water due to Properties of water due to hydrogen bondshydrogen bonds between water between water
molecules:molecules:• Exists as a liquid over a large range of temperatureExists as a liquid over a large range of temperature• Changes temperature slowlyChanges temperature slowly• High boiling point: 100High boiling point: 100˚C˚C• Adhesion and cohesionAdhesion and cohesion• Expands as it freezes Expands as it freezes • SolventSolvent• Filters out harmful UVFilters out harmful UV
Carbon Cycle Depends on Carbon Cycle Depends on Photosynthesis and RespirationPhotosynthesis and Respiration
• Link between photosynthesis in producers and respiration in Link between photosynthesis in producers and respiration in producers, consumers, and decomposersproducers, consumers, and decomposers
• Additional COAdditional CO2 2 added to the atmosphereadded to the atmosphere• Tree clearingTree clearing• Burning of fossil fuelsBurning of fossil fuels
Nitrogen Cycles through the Nitrogen Cycles through the Biosphere: Bacteria in ActionBiosphere: Bacteria in Action
• Nitrogen fixedNitrogen fixed• LightningLightning• Nitrogen-fixing bacteriaNitrogen-fixing bacteria
• Nitrification Nitrification • DenitrificationDenitrification
Nitrogen Cycles through the Nitrogen Cycles through the Biosphere: Bacteria in ActionBiosphere: Bacteria in Action• Human intervention in the nitrogen cycleHuman intervention in the nitrogen cycle
• Additional NO and NAdditional NO and N22O O • Destruction of forest, grasslands, and wetlandsDestruction of forest, grasslands, and wetlands• Add excess nitrates to bodies of waterAdd excess nitrates to bodies of water• Remove nitrogen from topsoilRemove nitrogen from topsoil
Phosphorus Cycles through the Biosphere• Cycles through water, the earth’s crust, and living organisms
• May be limiting factor for plant growth
• Impact of human activities• Clearing forests• Removing large amounts of phosphate from the earth to
make fertilizers
Sulfur Cycles through the BiosphereSulfur Cycles through the Biosphere
• Sulfur found in organisms, ocean sediments, soil, rocks, and Sulfur found in organisms, ocean sediments, soil, rocks, and fossil fuelsfossil fuels
• SOSO22 in the atmosphere in the atmosphere
• HH22SOSO44 and SO and SO44- -
• Human activities affect the sulfur cycleHuman activities affect the sulfur cycle• Burn sulfur-containing coal and oilBurn sulfur-containing coal and oil• Refine sulfur-containing petroleumRefine sulfur-containing petroleum• Convert sulfur-containing metallic mineral oresConvert sulfur-containing metallic mineral ores
3-6 How Do Scientists Study 3-6 How Do Scientists Study Ecosystems?Ecosystems?• Concept 3-6 Scientists use field research, laboratory
research, and mathematical and other models to learn about ecosystems.
Some Scientists Study Nature DirectlySome Scientists Study Nature Directly
• Field research: “muddy-boots biology”Field research: “muddy-boots biology”• New technologies availableNew technologies available
• Remote sensorsRemote sensors• Geographic information system (GIS) softwareGeographic information system (GIS) software• Digital satellite imagingDigital satellite imaging
• 2005, Global Earth Observation System of Systems (GEOSS)2005, Global Earth Observation System of Systems (GEOSS)
Some Scientists Study Ecosystems Some Scientists Study Ecosystems in the Laboratoryin the Laboratory
• Simplified systems carried out inSimplified systems carried out in• Culture tubes and bottlesCulture tubes and bottles• Aquaria tanksAquaria tanks• GreenhousesGreenhouses• Indoor and outdoor chambersIndoor and outdoor chambers
• Supported by field researchSupported by field research