ecosystems: how do they work?
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ECOSYSTEMS: ECOSYSTEMS: How do they work How do they work
Living in the EnvironmentLiving in the Environment
1414thth Edition Edition
Chapter 4Chapter 4
Shohail ChoudhuryShohail ChoudhuryShohail ChoudhuryShohail Choudhury
ECOLOGYECOLOGY
Ecology is the study of Ecology is the study of connections in the natural connections in the natural world world (Figure).(Figure).
An Ecosystem is a community of An Ecosystem is a community of different species interacting with each different species interacting with each other and with their nonliving other and with their nonliving environment for matter and energy. environment for matter and energy.
About 1.4 million of species identified. About 1.4 million of species identified. Estimate: 3.6 to 100 Estimate: 3.6 to 100 million. million.
Any form of life=Organism. Any form of life=Organism.
Earth’s Life Support SystemEarth’s Life Support System
Atmosphere
Vegetation and animals
Soil
Rock
Biosphere
Crust
core
MantleLithosphere
Crust
Lithosphere(crust, top of upper mantle)
Hydrosphere(water)
Atmosphere(air)
Biosphere(Living and dead
organisms)
Crust(soil and rock)
Troposphere: Troposphere: Sea level -11 miles
Stratosphere:Stratosphere:11-30 miles. Filters.
Lithosphere:Lithosphere: Fuels and minerals.
The Source of EnergyThe Source of Energy
Solarradiation
Energy in = Energy out
Reflected byatmosphere (34%)
UV radiation
Absorbedby ozone
Absorbedby the earth
Visiblelight
Lower Stratosphere(ozone layer)
Troposphere
Heat
Greenhouseeffect
Radiated byatmosphere
as heat (66%)
Earth
Heat radiatedby the earth
Solar energy makes the Solar energy makes the earth warm to support life.earth warm to support life.
Sustaining life of earthSustaining life of earth
•One way of energy flowOne way of energy flow
•Cycling of mattersCycling of matters
Ecosystem ComponentsEcosystem Components
15,000 ft10,000 ft5,000 ft
Coastalmountainranges
SierraNevadaMountain
GreatAmericanDesert
RockyMountains
GreatPlains
MississippiRiver Valley
AppalachianMountains
Coastal chaparraland scrub
DesertConiferousforest
Coniferousforest
Prairiegrassland
Deciduousforest
Average annual precipitaion100-125 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.)
Biomes: Terrestrial parts Biomes: Terrestrial parts of the biosphere. Desert, of the biosphere. Desert, Grassland. Grassland.
Role of climateRole of climate
Aquatic life zonesAquatic life zones
Ecosystem ComponentsEcosystem Components
15,000 ft10,000 ft5,000 ft
Coastalmountainranges
SierraNevadaMountain
GreatAmericanDesert
RockyMountains
GreatPlains
MississippiRiver Valley
AppalachianMountains
Coastal chaparraland scrub
DesertConiferousforest
Coniferousforest
Prairiegrassland
Deciduousforest
Average annual precipitaion
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.)Fig: Major biomes found along the 39th parallel across the USA. The difference reflects changes in climate (precipitation and temperature).
Components of EcosystemComponents of Ecosystem
Po
pu
lati
on
siz
e
Low High Temperature
Zone ofintolerance
Zone ofphysiological stress
Optimum range Zone ofphysiological stress
Zone ofintolerance
Noorganisms
Feworganisms
Lower limitof tolerance
Abundance of organismsFew
organismsNo
organisms
Upper limitof tolerance
Abiotic (Nonliving): Water, air, nutrients, solar energy.Abiotic (Nonliving): Water, air, nutrients, solar energy.
Biotic (Living): Plants, animals and microbes. Biotic (Living): Plants, animals and microbes.
Law of tolerance: Law of tolerance: Physical and chemical Physical and chemical factors. factors.
Limiting factor: Any Limiting factor: Any abiotic factor.abiotic factor.
Biotic Components of Ecosystem Biotic Components of Ecosystem
Heat
Heat Heat
Heat
Heat
Abiotic chemicalsAbiotic chemicals(carbon dioxide,(carbon dioxide,
oxygen, nitrogen,oxygen, nitrogen,minerals)minerals)
ProducersProducers(plants)(plants)
DecomposersDecomposers(bacteria, fungus)(bacteria, fungus)
ConsumersConsumers(herbivores, (herbivores,
Carnivores,omnivores)Carnivores,omnivores)
Solarenergy
ProducersProducers(autotrophs)(autotrophs)
PhotosynthesisPhotosynthesis
ConsumersConsumers(heterotrophs)(heterotrophs)
AerobicAerobicrespirationrespiration
DecomposersDecomposers
Trophic LevelsTrophic Levels
Fig: How chemical energy transfers through trophic levels. (Food Chain)
Food WebFood WebHumans
Blue whale Sperm whale
Crabeater seal
Killerwhale Elephant
seal
Leopardseal
Adéliepenguins Petrel
Fish
Squid
Carnivorous plankton
Krill
Phytoplankton
Herbivorouszooplankton
Emperorpenguin
Complex Network of Food ChainComplex Network of Food Chain
Less energy for high trophic level.Less energy for high trophic level.
Why few carnivores? Why few carnivores? (Tiger/Eagles) (Tiger/Eagles)
Why these are vulnerable Why these are vulnerable to extinction?to extinction?
Pyramid of Energy FlowPyramid of Energy Flow
Heat
Heat
Heat
Heat
Heat
1010
100100
1,0001,000
10,00010,000Usable energyUsable energy
Available atAvailable atEach tropic levelEach tropic level(in kilocalories)(in kilocalories)
ProducersProducers(phytoplankton)(phytoplankton)
Primaryconsumers
(zooplankton)
Secondaryconsumers
(perch)
Tertiaryconsumers
(human)
Decomposers
1.1. GeneticGenetic
2.2. SpeciesSpecies
3.3. EcologicalEcological
4.4. FunctionalFunctional
Biological DiversityBiological Diversity
Global Hydrologic CycleGlobal Hydrologic Cycle
Matter Cycling in EcosystemsMatter Cycling in Ecosystems
Human Human ActivityActivity
photosynthesisphotosynthesis aerobic aerobic respirationrespiration
Terrestrialrocks
Soil water(dissolved carbon)
Land food websproducers, consumers,
decomposers, detritivores
Atmosphere(mainly carbon dioxide)
Peat,fossil fuels
combustion of combustion of wood (for clearing wood (for clearing
land; or for fuelland; or for fuel
sedimentationsedimentation
volcanic actionvolcanic action
death, burial, compaction death, burial, compaction over geologic timeover geologic timeleaching leaching
runoffrunoff
weatheringweathering
The Carbon Cycle (Terrestrial) The Carbon Cycle (Terrestrial)
diffusion between diffusion between atmosphere and oceanatmosphere and ocean
Carbon dioxideCarbon dioxidedissolved in dissolved in ocean waterocean water
Marine food websMarine food websproducers, consumers, producers, consumers,
decomposers, detritivoresdecomposers, detritivores
Marine sediments, includingMarine sediments, includingformations with fossil fuelsformations with fossil fuels
combustion of fossil combustion of fossil fuelsfuels
incorporation incorporation into sedimentsinto sediments
death, death, sedimentationsedimentation
uplifting uplifting over over
geologic geologic timetime
sedimentationsedimentation
photosynthesisphotosynthesis aerobic aerobic respirationrespiration
The Carbon Cycle (Aquatic)The Carbon Cycle (Aquatic)
How Do Ecologists Learn About Ecosystems?How Do Ecologists Learn About Ecosystems?How Do Ecologists Learn About Ecosystems?How Do Ecologists Learn About Ecosystems?
Field researchField research
Remote sensingRemote sensing
Geographic information systems (GIS)Geographic information systems (GIS)
Laboratory researchLaboratory research
Systems analysisSystems analysis
GIS and EcosystemGIS and Ecosystem
Critical nesting sitelocations
USDA Forrest Service
Topography
Habitat type
Real world
Private owner 1
USDAForest Service
Private owner 2
ForestWetland
GrasslandLake
Poster CompetitionPoster Competition
Chapter 6 has maps( shows you where your biomes Chapter 6 has maps( shows you where your biomes are located Fig 6-16 pg 111) and discusses biomes.are located Fig 6-16 pg 111) and discusses biomes.
The web - Search for pictures and more information.The web - Search for pictures and more information. Prepare your poster. Prepare your poster. Present it (during the lunch break or other suitable Present it (during the lunch break or other suitable
time). time). Worth 20 points. –15 points poster, 5 points notes on Worth 20 points. –15 points poster, 5 points notes on
other biomes when groups are presenting. other biomes when groups are presenting.
SpecimenSpecimen
The Nitrogen CycleThe Nitrogen Cycle
NO3-
IN SOIL
NITROGEN FIXATION
by industry for agriculture
FERTILIZERS
FOOD WEBS ON LAND
NH3, NH4+
IN SOIL
1. NITRIFICATION
bacteria convert NH4+
to nitrate (NO2-)
loss by leaching
uptake by uptake by autotrophsautotrophs
excretion, death, excretion, death, decompositiondecomposition
uptake by uptake by autotrophsautotrophs
NITROGEN FIXATIONbacteria convert to
ammonia (NH3+) ; this
dissolves to form
ammonium (NH4+)
loss by leaching
AMMONIFICATIONbacteria, fungi convert
the residues to NH3 , this
dissolves to form NH4+
2. NITRIFICATION
bacteria convert NO2-
to nitrate (NO3-)
DENTRIFICATIONDENTRIFICATIONby bacteria
NITROGENOUS WASTES, REMAINS IN SOIL
GASEOUS NITROGEN
(N2) IN ATMOSPHERE
NO2-
IN SOIL
The Phosphorus CycleThe Phosphorus Cycle
Guano
FERTILIZER
ROCKS
LAND FOOD WEBS
DISSOLVED IN OCEAN
WATER
MARINE FOOD WEBS
MARINE SEDIMENTS
weatheringweathering
agricultureagriculture
uptake by uptake by autotrophsautotrophs
death, death, decompositiondecomposition
sedimentationsedimentationsettling settling
outout leaching, leaching, runoffrunoff
weatheringweathering DISSOLVED IN SOILWATER,
LAKES, RIVERS
uptake by uptake by autotrophsautotrophs
death, death, decompositiondecomposition
uplifting over
geologic time
uplifting uplifting over over
geologic geologic timetime
miningminingmining
excretionexcretionexcretion
Fertilizers
Detergents
Cutting tropical rainforests
Fertilizers
Detergents
Cutting tropical rainforests
The Sulphur CycleThe Sulphur Cycle