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8/8/2019 ENVI SCI Lecture 3
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1/10/201
ENVIRONMENTAL SCIENCE 13e
CHAPTER 3:Ecosystems: What AreThey and How Do
They Work?
Earth Has Four Major Life-Support Components
Atmosphere (air)
Hydrosphere Geosphere (lithosphere)
Biosphere
Fig. 3-2, p. 41
Rock
Crust
Atmosphere
Vegetationand animals
Biosphere
Mantle
Lithosphere
Soil
Geosphere(crust, mantle, core)
Mantle
Core
Crust(soil and rock)
Biosphere(living organisms)
Atmosphere(air)
Hydrosphere(water)
Three Factors Sustain Life onEarth
One-way flow of high-quality energyfrom the sun
Cycling of matter or nutrients through
parts of the biosphere
Gravity
Levels of Organization of
Matter in Nature
Ecologyfocuses on fiveof these levels
Organism
Any formof life
Can be
classifiedintospecies
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Ecosystems
All members of a community,
along with their physical andchemical environments
Vary greatly in size
Diversity promotes stability andproductivity
Dynamic energy flow
chemical cycling
Change over time (succession)
Coral Reefs are a rich,diverse and productive
ecosystems
A coastal wetland onLake Superior,
Wisconsin.
Ecology
How organisms interact with biotic
and abiotic environment Focuses on specific levels of matter:
Organisms
Populations
Communities
Ecosystems
Biosphere
Fig. 3-4, p. 42
Smallest unit of a chemical elementthat exhibits its chemical properties
Biosphere
Ecosystem
Community
Population
Organism
Cell
Molecule
Atom
Parts of the earth's air,water, and soilwhere life is found
Acommunity of different speciesinteracting with one another and with
their nonliving environment of matterand energy
Populations of different speciesliving in a particular place, and
potentially interacting with eachother
A group of individuals of the samespecies living in a particular place
An individual living being
The fundamental structural andfunctional unit of life
Chemical combination of two ormore atoms of the same or different
elements
Fig. 3-4, p. 42
Water
Hydrogen Oxygen
Living and NonlivingComponents (1)
Abiotic Water
Air
Nutrients
Solar energy
Rocks
Heat
Living and NonlivingComponents (2)
Biotic Plants
Animals
Microbes
Dead organisms
Waste products of dead organisms
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Soluble mineralnutrients
Producers
Decomposers
Secondaryconsumer
(fox)
Carbon dioxide (CO2)
Primaryconsumer
(rabbit)
Producer
Oxygen (O2)Precipitation
Water
Fig. 3-5, p. 43
Trophic Levels (1)
Producers autotrophs
Photosynthesis
Consumers heterotrophs
Primary - herbivores
Secondary - carnivores
Third-level- Omnivores
Trophic Levels (2)
Decomposers
Release nutrients from the dead bodies
of plants and animals
Detrivores
Feed on the waste or dead bodies of
organisms
Time
progression Powder broken dow n by
decomposers into plantnutrients in soil
MushroomWoodreducedto powder
Dry rotfungus
Termite andcarpenterant work
DecomposersDetritus feeders
Carpenterant galleriesBark beetle
engravingLong-hornedbeetle holes
Fig. 3-6, p. 44
Primary Production
The conversion of light
energy to chemical energy iscalled gross primary
production. (photosynthesis)
Plants use the energy
captured in photosynthesis
for maintenance and growth.
The energy that is
accumulated in plant
biomass is called net
primary production.
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Biological Processes
Photosynthesis
Respiration
Photosynthetically ActiveRadiation (PAR)
Light
wavelenghts:400 700 nm
Drivesphotosynthetic
reactions
Photosynthesis
The Leaf as Site ofPhotosynthesis
PhotosyntheticPathways
C3(Calvin Cycle)
C4 (Hatch andSlack)
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CrassulaceanAcidMetabolism(CAM) Photosynthetic
pathway forxerophytic plants
Dissimilar Organisms with Similar Approaches to Desert Living
Water Conservation of
Rain Forest Plants
Temporarywilting reducesleaf surfacearea for
transpiration.
Production and Consumption ofEnergy
Photosynthesis
Carbon dioxide + water + solarenergyglucose + oxygen
Aerobic respiration
Glucose + oxygen carbon dioxide+ water + energy
Energy Flow and NutrientRecycling
Ecosystems sustained through: One-way energy flow from the sun
Nutrient recycling
Abiotic chemicals(carbon dioxide,
oxygen, nitrogen,minerals)
Decomposers(bacteria, fungi)
Consumers(herbivores,carnivores)
Producers(plants)
Solarenergy
Heat
Heat Heat
Heat Heat
Fig. 3-7, p. 45
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Science Focus: InvisibleOrganisms (1)
Microorganisms/Microbes
Bacteria Protozoa
Fungi
Phytoplankton
Science Focus: InvisibleOrganisms (2)
Microbes can cause disease
Malaria Athletes foot
Microbes are also beneficial
Intestinal flora
Purify water
Phytoplankton remove carbon dioxidefrom the atmosphere
Energy Flow in Ecosystems
Food chains and web show how eaters,the eaten, and the decomposed areconnected to one another.
Food chain is a sequence of organisms,each of which is a source of food for thenext.
Food web is a complex network of
interconnected food chains.
A Food Chain
Humans
Squid
Herbivorouszooplankton
Phytoplankton
Krill
Fish
Petrel
Adeliepenguin
Sperm whale
Emperorpenguin
Leopardseal
Killer
whale
Crabeaterseal
Elephantseal
Blue whale
Carnivorousplankton
Fig. 3-9, p. 46
Two Kinds of PrimaryProductivity
Gross primary productivity (GPP)
Net primary productivity (NPP)
Planets NPP limits number ofconsumers
Humans use, waste, or destroy 10-55% of earths total potential NPP
Human population is less than 1% oftotal biomass of earths consumers
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3-4 What Happens to Matter inan Ecosystem?
Concept 3-4Matter, in the form of
nutrients, cycles within and amongecosystems and in the biosphere, andhuman activities are altering thesechemical cycles.
Biogeochemical Cycles
Nutrient cycles
Reservoirs Connect all organisms through time
Hydrologic Cycle
Water cycle is powered by the sun
1. Evaporation
2. Precipitation
3. Transpiration - evaporates from plant
surfaces
Water vapor in the atmosphere comes
from the oceans 84%
Over land, ~90% of water reaching theatmosphere comes from transpiration
Increasedfloodingfrom wetlanddestruction
Condensation
Evaporationfrom ocean
Climatechange
Infiltrationand percolationinto aquifer
Condensation
Ocean
Lakes andreservoirs
Ice andsnow
Surfacerunoff
Surface runoff
Aquiferdepletion fromoverpumping
Pointsourcepollution
Reduced recharge ofaquifers and floodingfrom covering landwith crops andbuildings
Groundwatermovement (slow)
Runoff
Precipitationto land
Precipitationto ocean
Transpirationfrom plants
Evaporationfrom land
Fig. 3-12, p. 49
Processes
Processes affected by humans
Reservoir
Pathway affected by humans
Natural pathway
Carbon Cycle
Based on carbon dioxide (CO2)
CO2 makes up 0.038% of atmospherevolume
Major cycle processes Aerobic respiration
Photosynthesis
Fossil fuel combustion and deforestation
Fossil fuels add CO2 to the atmosphereand contribute to global warming
Respiration
Forest fires
Deforestation
Diffusion
Carbon dioxidedissolved in ocean
Carbonin limestone or
dolomite sediments
Marine food websProducers, consumers,
decomposers
Transportation
Carbon dioxidein atmosphere
Carbonin animals
(consumers)
Plants(producers)
Animals(consumers)
Decomposition
Respiration
Compaction
Carbonin fossil
fuels
Carbonin plants
(producers)
Burningfossil fuels
Photosynthesis
Fig. 3-13, p. 51
Processes
Reservoir
Pathway affected by humans
Natural pathway
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Nitrogen Cycle
Multicellular plants and animals
cannot utilize atmospheric nitrogen(N2)
Nitrogen fixation (N2 --- NO3 )
Nitrification (NO3 --- NH4)
Denitrification
Nitrogenin atmosphere
Nitrogenloss to deepocean sediments
Nitrogen oxidesfrom burning fuel
Nitratesfrom fertilizer
runoff anddecomposition
Nitrogenin oceansediments Ammonia
in soil
Volcanicactivity
Electricalstorms Nitrogen
in animals(consumers)
Bacteria
Nitrate
in soil
Nitrogenin plants
(producers)
Nitrificationby bacteria
Denitrificationby bacteria
Uptake by plantsDecomposition
Fig. 3-14, p. 52
Processes
Reservoir
Pathway affected by humans
Natural pathway
Phosphorus Cycle
Does not cycle through theatmosphere
Obtained from terrestrial rock
formations
Limiting factor on land and infreshwater ecosystems
Biologically important for producers
and consumersFig. 3-15, p. 53
Seabirds
Phosphatein shallowocean sediments
Bacteria
Animals(consumers)
Plants
(producers)
Runoff
Runoff Runoff
Phosphatesin fertilizer
Phosphates
in mining waste
Phosphatesin sewage
Phosphatedissolved inwater
Erosion
Phosphatein deepocean
sediments
Oceanfood chain
Platetectonics
Phosphatein rock
(fossil bones,guano)
Fig. 3-15, p. 53
Processes
Reservoir
Pathway affected by humans
Natural pathway
Sulfur Cycle
Most sulfur stored in rocks and minerals Enters atmosphere through:
Volcanic eruptions and processes
Anaerobic decomposition in swamps,bogs, and tidal flats
Sea spray
Dust storms
Forest fires
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