Ecosystems
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Ecosystems. Studying organisms in their environment. biosphere. ecosystem. community. population. organism. Essential questions. What limits the production in ecosystems? How do nutrients move in the ecosystem? How does energy move through the ecosystem?. Ecosystem.

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Ecosystems

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Ecosystems

Ecosystems


Studying organisms in their environment

Studying organisms in their environment

biosphere

ecosystem

community

population

organism


Essential questions

Essential questions

  • What limits the production in ecosystems?

  • How do nutrients move in the ecosystem?

  • How does energy move through the ecosystem?


Ecosystem

Ecosystem

  • All the organisms in a community plus abiotic factors

    • ecosystems are transformers of energy& processors of matter

  • Ecosystems are self-sustaining

    • what is needed?

  • capture energy

  • transfer energy

  • cycle nutrients


Ecosystem inputs

Ecosystem inputs

biosphere

constant inputof energy

energy flowsthrough

nutrients cycle

Don’t forgetthe laws of Physics!

Matter cannot

be created ordestroyed

nutrients can only cycle

inputs

  • energy

  • nutrients


Participants in an ecosystem

Participants in an Ecosystem

  • Primary producers-autotrophs that make up the first trophic level of any ecosystem

    • Ex-plants, phytoplankton, & some bacteria

  • Consumers-heterotrophs that feed on the tissues, products, and remains of other organisms

    • Ex=herbivores, carnivores, omnivores, parasites, detritivores, decomposers


Decomposers vs detritivores

Decomposers vs Detritivores

  • Detritivores eat particles of decomposing matter(detritus)

  • Types-

    • Scavengers-animals that feed on

      carrion, dead plant matter, or refuse.

      Ex-buzzards, ants, & vultures

    • Decomposersbreak down organic remains and wastes off all organisms and return nutrients to earth

      • Ex-bacteria, protists, and fungi


Energy flows through ecosystems

loss of energy

loss of energy

Energy flows through ecosystems

sun

secondary consumers

(carnivores)

primary consumers

(herbivores)

producers (plants)


Inefficiency of energy transfer

sun

energy lost todaily living

energy lost todaily living

Inefficiency of energy transfer

  • Loss of energy between levels of food chain(only 10% is transferred b/t trophic levels)

    • To where is the energy lost? The cost of living!

17%

growth

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

33%

cellular

respiration

50%

waste (feces)


Food chains

sun

Level 4

Tertiary consumer

Food chains

  • Trophic levels

    • feeding relationships

    • start with energy from the sun

    • captured byplants

      • 1st level of all food chains

    • food chains usually go up only 4 or 5 levels

      • inefficiency of energy transfer

    • all levels connect to decomposers

top carnivore

Level 3

Secondary consumer

carnivore

Level 2

Primary consumer

heterotrophs

herbivore

Level 1

Producer

autotrophs

Fungi

Decomposers

Bacteria


Food webs

Food webs

  • Food chains are linked together into food webs

  • Who eats whom?

    • a species may weave into web at more than one level

      • bears

      • humans

        • eating meat?

        • eating plants?


Types of food webs

Types of Food Webs

  • Grazing food web-energy flows mostly into herbivores, carnivores, then decomposers

  • Detrital food web-energy from producers flows mainly into detritivores and decomposers.


Biological magnification in food webs

Biological Magnification in Food Webs

  • In biological magnification, some chemical substance is passed from organisms at one trophic level to those above and becomes increasingly concentrated in body tissues.

  • By 1995, people in the US were spreading more than 1.25 billion pounds of toxins per year! (insecticides, herbicides, fungicides…)

  • Example- The peregrine falcon almost became extinct as a result of biomagnification of DDT (a pesticide). DDT has been banned since the 70’s.


Ecological pyramid

sun

Ecological pyramid

  • Loss of energy between levels of food chain

1

100

100,000

1,000,000,000


Ecosystems

  • Types of ecological pyramids

    • Biomass pyramid-depicts the dry weight of all of an ecosystem’s organisms at each tier

    • Energy pyramid-illustrates how the amount of usable energy diminishes as it is transferred through an ecosystem

    • Pyramid of numbers-shows how population size decreases as you go from producer to consumer


Generalized nutrient cycling

Decompositionconnects all trophic levels

Generalized Nutrient cycling

consumers

consumers

producers

consumers

decomposers

decomposers

nutrientsENTER FOOD CHAIN= made availableto producers

nutrientsmade availableto producers

return toabioticreservoir

abioticreservoir

abioticreservoir

geologicprocesses

geologicprocesses


Ecosystems

  • In a biogeochemical cycle , an essential element moves from the environment, through ecosystems, then back to the environment.

  • Ex: O2,H,C,N, & P


Carbon cycle

CO2 in

atmosphere

Combustion of fuels

Industry and home

Photosynthesis

Diffusion

Respiration

Plants

Animals

Dissolved CO2

Bicarbonates

Photosynthesis

Deposition

of dead

material

Animals

Plants and algae

Fossil fuels

(oil, gas, coal)

Deposition of

dead material

Carbonates in sediment

  • abiotic reservoir:

    • CO2 in atmosphere

  • enter food chain:

    • photosynthesis = carbon fixation in Calvin cycle

  • recycle:

  • return to abiotic:

    • respiration

    • combustion

Carbon cycle


Nitrogen cycle

  • abiotic reservoir:

    • N in atmosphere

  • enter food chain:

    • nitrogen fixation by soil & aquatic bacteria

  • recycle:

    • decomposing & nitrifying bacteria

  • return to abiotic:

    • denitrifying bacteria

Nitrogen cycle

Atmospheric

nitrogen

Carnivores

Herbivores

Birds

Plants

Plankton with

nitrogen-fixing

bacteria

Death, excretion, feces

Nitrogen-fixing

bacteria

(plant roots)

Fish

Decomposing bacteria

amino acids

excretion

Nitrogen-fixing

bacteria

(soil)

Ammonifying bacteria

loss to deep sediments

Nitrifying bacteria

Denitrifying

bacteria

soil nitrates


Ecosystems

  • Nitrogen fixation-bacteria convert gaseous nitrogen to ammonia

  • Denitrification-conversion of nitrate or nitrite to gaseous nitrogen or nitrogen oxide by certain bacteria in the soil

  • Human activities add nitrogen to ecosystems. Use of fertilizer and fossil fuel burning are examples


Phosphorus cycle

  • abiotic reservoir:

    • rocks, minerals, soil

  • enter food chain:

    • erosion releases soluble phosphate

    • uptake by plants

  • recycle:

    • decomposing bacteria & fungi

  • return to abiotic:

    • loss to ocean sediment

Phosphorus cycle

Land

animals

Plants

Animal tissue

and feces

Urine

Soluble soil

phosphate

Decomposers

(bacteria and

fungi)

Loss in

drainage

Rocks and

minerals

Phosphates

in solution

Decomposers

(bacteria & fungi)

Animal tissue

and feces

Plants and

algae

Aquatic

animals

Precipitates

Loss to deep sediment


Ecosystems

  • abiotic reservoir:

    • surface & atmospheric water

  • enter food chain:

    • precipitation & plant uptake

  • recycle:

    • transpiration

  • return to abiotic:

    • evaporation & runoff

Water cycle

Solar energy

Transpiration

Water vapor

Evaporation

Precipitation

Oceans

Runoff

Lakes

Percolation in soil

Aquifer

Groundwater


Transpiration

Transpiration

Remembertranspiration?


Breaking the water cycle

Breaking the water cycle

  • Deforestation breaks the water cycle

    • groundwater is not transpired to the atmosphere, so precipitation is not created

forest  desert

desertification


Repairing the damage

WangariMaathai

Repairing the damage

  • The Greenbelt Movement

    • planting trees in Kenya

    • restoring a sustainable ecosystem

    • establishing democracy

    • empowering women

Nobel Peace prize 2004


Studying ecosystems

7800 acres

Studying ecosystems

38 acre deforestation

Hubbard Brook Experimental Forest


Effects of deforestation

Effects of deforestation

40% increase in runoff

  • loss of water

  • 60x loss in nitrogen

  • 10x loss in calcium

loss into surface water

nitrate levels in runoff

80

40

loss out of ecosystem!

Concentration

of nitrate (mg/l )

4

Deforestation

2

Why isnitrogen soimportant?

0

1965

1966

1967

1968

Year


A global water crisis

A Global Water Crisis

  • Most water on Earth is too salty to drink (around 75%)

  • 2/3 of fresh water is used to irrigate fields

  • About ½ of the US population taps into groundwater for drinking water that can be contaminated.

  • If the US population and water depletion continues, our freshwater supply will be in danger.

  • Important terms:

    • Salinization-a build up of salt in soil that stunts crop plants and decreases yields.

    • Desalination-removal of salt from sea water


Greenhouse gases global warming

Greenhouse Gases, Global Warming

  • The greenhouse effect occurs when greenhouse gases trap heat in the lower atmosphere.

    • This makes Earth’s surface warm enough to support life.

  • Natural processes and human activities are adding more greenhouse gases to the atmosphere.

    • Examples: carbon dioxide, CFCs, methane, & nitrous oxide

  • This results in a result in global warming and climate change.


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