Ecosystems

Ecosystems

biosphere

ecosystem

community

population

Studying organisms in their environment

organism

Essential questionsWhat limits the production in ecosystems?

How do nutrients move in the ecosystem?

How does energy move through the ecosystem?

EcosystemAll the organisms in a community plus

abiotic factorsecosystems are transformers of energy

& processors of matter

Ecosystems are self-sustainingSunlight is needed only

capture energy transfer energy cycle nutrients

capture energy transfer energy cycle nutrients

biosphere

Ecosystem inputs

constant inputof energyenergy flowsthrough

nutrients cycle

nutrients can only cycle

Inputs: energy nutrients

Inputs: energy nutrients

Don’t forgetthe laws of Physics!

Matter cannotbe created ordestroyed

consumers

decomposers

abioticreservoir

nutrientsmade availableto producers

geologicprocesses

Generalized Nutrient

cycling

consumers

consumers

producers

decomposers

abioticreservoir

nutrientsENTER FOOD CHAIN= made availableto producers

geologicprocesses

Decompositionconnects all trophic levels

return toabioticreservoir

Carbon cycle

CO2 inatmosphere

Diffusion RespirationPhotosynthesis

Photosynthesis

Plants and algae

PlantsAnimals

Industry and home

Combustion of fuels

Animals

Carbonates in sediment

Bicarbonates

Deposition ofdead material

Depositionof deadmaterial

Fossil fuels(oil, gas, coal)

Dissolved CO2

abiotic reservoir: CO2 in atmosphere

enter food chain: photosynthesis = carbon fixation in Calvin cycle

Recycle: decompositionreturn to abiotic: respiration Combustion of fossil fuels

abiotic reservoir: CO2 in atmosphere

enter food chain: photosynthesis = carbon fixation in Calvin cycle

Recycle: decompositionreturn to abiotic: respiration Combustion of fossil fuels

Birds

Herbivores

Plants

amino acids

CarnivoresAtmosphericnitrogen

loss to deep sediments

Fish

Plankton withnitrogen-fixingbacteria

Nitrogen-fixingbacteria(plant roots)

Nitrogen-fixingbacteria (soil)

Denitrifyingbacteria

Death, excretion, feces

Nitrifying bacteria

soil nitrates

excretion

Decomposing bacteria

Ammonifying bacteria

Nitrogen cycle

abiotic reservoir: N in atmosphere

enter food chain: nitrogen fixation

by soil & aquatic bacteria

recycle: decomposing &

nitrifying bacteriareturn to abiotic: denitrifying

bacteria

abiotic reservoir: N in atmosphere

enter food chain: nitrogen fixation

by soil & aquatic bacteria

recycle: decomposing &

nitrifying bacteriareturn to abiotic: denitrifying

bacteria

Lakes

Runoff

Percolation in soil

Evaporation

Transpiration

Precipitation

Oceans

Solar energy

AquiferGroundwater

Water cycle

Water vapor

abiotic reservoir: surface &

atmospheric waterenter food chain: precipitation &

plant uptakerecycle: transpiration

return to abiotic: evaporation &

runoff

abiotic reservoir: surface &

atmospheric waterenter food chain: precipitation &

plant uptakerecycle: transpiration

return to abiotic: evaporation &

runoff

biosphere

Ecosystem inputsenergy flowsthrough

nutrients cycle

inputs energy nutrients

inputs energy nutrients

Energy flows through ecosystems

sun

producers (plants)producers (plants)

loss of energy

loss of energy

secondary consumers(carnivores)

secondary consumers(carnivores)

primary consumers(herbivores)

primary consumers(herbivores)

Food chainsTrophic levels

feeding relationshipsstart with energy from

the sun captured by plants

1st level of all food chainsfood chains usually go

up only 4 or 5 levelsDue to inefficiency of

energy transferall levels connect to

decomposers Fungi

Level 4

Level 3

Level 2

Level 1

Decomposers

Producer

Primary consumer

Secondary consumer

Tertiary consumer

top carnivore

carnivore

herbivore

Bacteria

autotrophs

heterotrophs

sun

Inefficiency of energy transferLoss of energy between levels of food

chainTo where is the energy lost? The cost of living!

only this energymoves on to the next level in the food chain

17%growth

50%waste (feces)

33%cellularrespiration

energy lost todaily livingenergy lost todaily living

sun

Ecological pyramidLoss of energy between levels of food chain

can feed fewer animals in each levelFewr organisms at the top due to energy loss

1,000,000,000

100,000

100

1

sun

Humans in food chains

Dynamics of energy through ecosystems have important implications for human populationshow much energy does it take to feed a

human? if we are meat eaters? Vegetarians?

What is yourecological footprint?!

Food websFood chains are linked

together into food webs

Who eats whom? a species may weave

into web at more than one

levelbearshumans

eating meat?eating plants?