lecture(Community Structure)Sans Photos

8/14/2019 lecture(Community Structure)Sans Photos

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EcosystemscosystemsChapter 48Chapter 48


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EcosystemEcosystem

An association of organisms and theirAn association of organisms and their

physical environment, interconnectedphysical environment, interconnected

by ongoing flow of energy and aby ongoing flow of energy and a

cycling of materialscycling of materials


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Mo des of N utr it iono des of N utr it ion AutotrophsAutotrophs

Capture sunlight or chemical energyCapture sunlight or chemical energy

ProducersProducers

HeterotrophsHeterotrophs

Extract energy from other organisms orExtract energy from other organisms or

organic wastesorganic wastes

Consumers, decomposers, detritivoresConsumers, decomposers, detritivores


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Tr ophic Leve lsr ophic Leve ls All the organisms at a trophic level areAll the organisms at a trophic level are

the same number of steps away from thethe same number of steps away from the

energy input into the systemenergy input into the system

Producers are closest to the energy inputProducers are closest to the energy input

and are the first trophic leveland are the first trophic level


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An sw er 1n sw er 1 1. Define:1. Define: ecosystem.ecosystem.

An association of organisms and theirAn association of organisms and their

physical environment, interconnectedphysical environment, interconnected

by ongoing flow of energy and aby ongoing flow of energy and a

cycling of materials.cycling of materials.


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Qu estio n 2u estio n 2 2. Compare and contrast: herbivore and2. Compare and contrast: herbivore and

carnivore,carnivore,


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An sw er 2n sw er 2 2. Compare and contrast: herbivore and2. Compare and contrast: herbivore and

carnivore.carnivore.

Herbivores eat plants and carnivoresHerbivores eat plants and carnivores

eat animals.eat animals.


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Qu estio n 3u estio n 3 3. Compare and contrast: omnivore and3. Compare and contrast: omnivore and

detritivore.detritivore.


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An sw er 3n sw er 3 3. Compare and contrast: omnivore and3. Compare and contrast: omnivore and

detritivore.detritivore.

Omnivores eat both animals andOmnivores eat both animals andplants.plants.

Detritivores eat the dead animal andDetritivores eat the dead animal andplant material (in the soil or water).plant material (in the soil or water).


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Energy LossesEnergy Losses

Energy transfers are never 100Energy transfers are never 100

percent efficientpercent efficient

Some energy is lost at each stepSome energy is lost at each step

Limits the number of trophic levels inLimits the number of trophic levels in

an ecosysteman ecosystem


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Biological MagnificationBiological Magnification

A nondegradable or slowly degradableA nondegradable or slowly degradable

substance becomes more and moresubstance becomes more and more

concentrated in the tissues ofconcentrated in the tissues of

organisms at higher trophic levels of aorganisms at higher trophic levels of a

food webfood web


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DDT in Food We bsDT in Food We bs Synthetic pesticideSynthetic pesticide

banned in the Unitedbanned in the United

States since the 1970sStates since the 1970s Birds that were topBirds that were top

carnivores accumulatedcarnivores accumulated

DDT in their tissuesDDT in their tissues


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Primary ProductivityPrimary Productivity

GrossGross primary productivity isprimary productivity is

ecosystems total rate ofecosystems total rate of

photosynthesisphotosynthesis

NetNet primary productivity is rate atprimary productivity is rate at

which producers store energy inwhich producers store energy in


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Pr imary Pr oductivityr imary Pr oductivityVariesaries

Seasonal variationSeasonal variation

Variation by habitatVariation by habitat

The harsher the environment, theThe harsher the environment, the

slower plant growth, the lower theslower plant growth, the lower the

primary productivityprimary productivity


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All He at in the Endll He at in the End At each trophic level, the bulk of theAt each trophic level, the bulk of the

energy received from the previous levelenergy received from the previous level

is used in metabolismis used in metabolism

This energy is released as heat energyThis energy is released as heat energy

and lost to the ecosystemand lost to the ecosystem

Eventually, all energy is released as heatEventually, all energy is released as heat


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Qu estio n 4u estio n 44. Define:4. Define: biomagnification.biomagnification.


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An sw er 4 ( STO PPEDn sw er 4 ( STO PPEDHere)ere)

4. Define:4. Define: biomagnification.biomagnification.

A nondegradable or slowly degradableA nondegradable or slowly degradable

substance becomes more and moresubstance becomes more and more

concentrated in the tissues of organismsconcentrated in the tissues of organisms

at higher trophic levels of a food webat higher trophic levels of a food web


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Qu estio n 5u estio n 55. Which organisms are most at risk from5. Which organisms are most at risk from

biomagnification?biomagnification?


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An sw er 5n sw er 55. Which organisms are most at risk from5. Which organisms are most at risk from


Predators at the high trophic levelsPredators at the high trophic levels


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An sw er 6n sw er 66. Compare and contrast:6. Compare and contrast: food chain andfood chain and

food web.food web.

A straight line sequence of who eatsA straight line sequence of who eats

whom food chain.whom food chain.

An interconnected set of food chains An interconnected set of food chains

food web.food web.


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Qu estio n 7u estio n 77. Compare an contrast: autotroph and7. Compare an contrast: autotroph and

heterotroph.heterotroph.


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An sw er 7n sw er 77. Compare an contrast: autotroph and7. Compare an contrast: autotroph and

heterotroph.heterotroph.

Autotrophs make their own food (photoAutotrophs make their own food (photo

or chemsynthesis)or chemsynthesis)

Heterotrophs cant make their own food.Heterotrophs cant make their own food.

They must graze or catch their food.They must graze or catch their food.


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Qu estio n 8u estio n 88. What is the ultimate fate of the solar8. What is the ultimate fate of the solar

energy that enters a food web?energy that enters a food web?


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An sw er 8n sw er 88. What is the ultimate fate of the solar8. What is the ultimate fate of the solar

energy that enters a food web?energy that enters a food web?

It is lost as heat.It is lost as heat.


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Qu estio n 9u estio n 99. Define:9. Define: bioaccumulation.bioaccumulation.


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An sw er 9n sw er 99. Define:9. Define:BioaccumulationBioaccumulation. The retention. The retention

of nonpolar molecules from our food orof nonpolar molecules from our food or

water. These molecules do not degradewater. These molecules do not degradevery fast. Example: DDT. Others mercuryvery fast. Example: DDT. Others mercury

and leadand lead


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Qu estio n 10u estio n 1010. Which organisms are most at risk from10. Which organisms are most at risk from



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An sw er 10n sw er 1010. Which organisms are most at risk from10. Which organisms are most at risk from


Top predators (carnivores)Top predators (carnivores)


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Qu estio n 11u estio n 1111. Can a predator and its parasite be on11. Can a predator and its parasite be on

the same trophic level? Explain.the same trophic level? Explain.


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An sw er 11n sw er 1111. Can a predator and its parasite be on11. Can a predator and its parasite be on

the same trophic level? Explain.the same trophic level? Explain.

No. A parasite dines on its host.No. A parasite dines on its host.

Therefore it is one more step from theTherefore it is one more step from the

sun (one higher trophic level).sun (one higher trophic level).


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Th ree Ca tegoriesh ree Ca tegories Hydrologic cycleHydrologic cycle

WaterWater

Atmospheric cyclesAtmospheric cycles

Nitrogen and carbonNitrogen and carbon

Sedimentary cyclesSedimentary cycles

Phosphorus and sulfurPhosphorus and sulfur


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Hu bbard Br ooku bbard Br ookExperimentxperiment A watershed was experimentally strippedA watershed was experimentally stripped

of vegetationof vegetation

All surface water draining fromAll surface water draining from

watershed was measuredwatershed was measured

Removal of vegetation caused a six-foldRemoval of vegetation caused a six-foldincrease in the calcium content of theincrease in the calcium content of the

runoff waterrunoff water


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Hu man Ef fectsu man Ef fects In tropical countries, clearing lands forIn tropical countries, clearing lands for

agriculture may deplete phosphorus-agriculture may deplete phosphorus-

poor soilspoor soils

In developed countries, phosphorusIn developed countries, phosphorus

runoff is causing eutrophication ofrunoff is causing eutrophication of

waterwayswaterways


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Qu estio n 12u estio n 129. Define:9. Define: biogeochemical cycle.biogeochemical cycle.


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An sw er 12n sw er 129. Define:9. Define: biogeochemical cycle.biogeochemical cycle.

The flow of a nutrient from theThe flow of a nutrient from the

environment to living organisms andenvironment to living organisms and

back to the environment.back to the environment.


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Qu estio n 13u estio n 1310. What are two cellular biochemicals that10. What are two cellular biochemicals that

must include phosphate in theirmust include phosphate in their

molecular structures?molecular structures?


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An sw er 13n sw er 1313. What are two cellular biochemicals that13. What are two cellular biochemicals that

must include phosphate in theirmust include phosphate in their

molecular structures?molecular structures?

Phospholipids and nucleotidesPhospholipids and nucleotides


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Nitrogen CycleNitrogen Cycle

Nitrogen is used in amino acids andNitrogen is used in amino acids and

nucleic acidsnucleic acids

Main reservoir is nitrogen gas in theMain reservoir is nitrogen gas in the

atmosphereatmosphere


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Am mo nific ation &m mo nific ation &Nit rific ationit rific ation Bacteria and fungi carry outBacteria and fungi carry out

ammonification, conversion ofammonification, conversion of

nitrogenous wastes to ammonianitrogenous wastes to ammonia

Nitrifying bacteria convert ammonium toNitrifying bacteria convert ammonium tonitrites and nitratesnitrites and nitrates


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Nit rogen L ossit rogen Loss Nitrogen is often a limiting factor in ecosystemsNitrogen is often a limiting factor in ecosystems

Nitrogen is lost from soils via leaching andNitrogen is lost from soils via leaching and

runoffrunoff

Denitrifying bacteria convert nitrates andDenitrifying bacteria convert nitrates and

nitrites to nitrogen gas (often occurs in waternitrites to nitrogen gas (often occurs in water

logged soil)logged soil)


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Hu man Ef fectsu man Ef fects Humans increase rate of nitrogen loss byHumans increase rate of nitrogen loss by

clearing forests and grasslandsclearing forests and grasslands

Humans increase nitrogen in water andHumans increase nitrogen in water and

air by using fertilizers and by burningair by using fertilizers and by burning

fossil fuelsfossil fuels

Too much or too little nitrogen canToo much or too little nitrogen can

compromise plant healthcompromise plant health


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Sew age spi ll hi tsew age spi ll hi tsPea chtree Creek,ea chtree Creek,Chat tahoocheehat tahoochee

Over a million gallonsOver a million gallons of raw sewage poured intoof raw sewage poured intoa creek Monday just upstream of the Chattahoocheea creek Monday just upstream of the ChattahoocheeRiver and near the spot where Atlanta draws itsRiver and near the spot where Atlanta draws itsdrinking water.drinking water.

Before a collapsed 36-inch sewer pipe was repaired,Before a collapsed 36-inch sewer pipe was repaired,sewage flowed into Peachtree Creek at the rate ofsewage flowed into Peachtree Creek at the rate of10,000 gallons a minute for two hours, said Janet10,000 gallons a minute for two hours, said JanetWard, a spokeswoman for Atlanta's WatershedWard, a spokeswoman for Atlanta's WatershedManagement Department.Management Department. The incident occurredThe incident occurred

near the Chattahoochee Water Treatmentnear the Chattahoochee Water TreatmentPlant off Bolton Road, where the city getsPlant off Bolton Road, where the city getsdrinking water.drinking water.

The Atlanta Journal-Constitution

Published on: 11/29/05

Dead Watersea a ers


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Dead Watersea a ersMassive oxygen-starved zones areMassive oxygen-starved zones are

developing along the world's coastsdeveloping along the world's coasts

Summer tourists cruising the watersSummer tourists cruising the waters

off Louisiana or Texas in the Gulf ofoff Louisiana or Texas in the Gulf ofMexico take in gorgeous vistas asMexico take in gorgeous vistas asthey pull in red snappers and bluethey pull in red snappers and bluemarlins. Few realize that the lower halfmarlins. Few realize that the lower half

of the water column below them mayof the water column below them maylack fish, despite the piscine bountylack fish, despite the piscine bountynear the surface.near the surface.


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Ni trates and Phosphatesi trates and PhosphatesCont rib utio ns f romont rib utio ns f romFerti lizerserti lizers Typically, they appear where a riverTypically, they appear where a river

spews rich plumes of nutrients into waterspews rich plumes of nutrients into water

that's stratified because of eitherthat's stratified because of eithertemperature or salinity differencestemperature or salinity differences

between the bottom and the top of thebetween the bottom and the top of the

water column. If the water doesn't mix,water column. If the water doesn't mix,

oxygen isn't replenished in the loweroxygen isn't replenished in the lower

half.half.


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Ba cte ria Use Up Mo sta cte ria Use Up Mo stof th e Of th e O 2 the Mississippi River deposits water that isthe Mississippi River deposits water that is

heavily enriched with plant nutrients, principallyheavily enriched with plant nutrients, principally

nitrate. This pollutant fertilizes the abundantnitrate. This pollutant fertilizes the abundant

growth of tiny, floating algae. As blooms of thegrowth of tiny, floating algae. As blooms of the

algae go through their natural life cycles andalgae go through their natural life cycles and

die, they fall to the bottom and create a feastdie, they fall to the bottom and create a feast

for bacteria. Growing in unnatural abundance,for bacteria. Growing in unnatural abundance,the bacteria use up most of the oxygen fromthe bacteria use up most of the oxygen from

the bottom water.the bottom water.

http://www.sciencenews.org/articles/20040605/bob9.asp


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Qu estio n 14u estio n 1414. How can this massive eutrophication14. How can this massive eutrophication

be halted and the system repaired?be halted and the system repaired?

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