Transcript Ch3 - Cycles in Nature

(Nutrients)
 Ecosystems need nutrients and energy
 Nutrients are
 Organisms transform nutrients
 Energy flows
“Circle of Life”
Organisms
Matter (Nutrients)
Environment
How do we
know energy
is flowing?
Why is this
cycle
important?
If something
removed?
Water molecules enter atmosphere as
water vapor (gas) by:
Evaporation-water changes to water
vapor
Transpiration-evaporation from the
leaves of plants
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How it works:
1.
Sun heats up the atmosphere,
water rises up and cools
2.
Water vapor condense to form
droplets then clouds
3.
Water droplets get bigger and
return to Earth as precipitation
(rain, snow, sleet or hail)
4.
Precipitation runs on land to river or
stream that carries the runoff back
to ocean or lake
Nutrient Cycles
Nutrients- organisms building blocks
or chemical needed to help
grow/carry out essential life
functions
3 nutrient cycles:

Carbon

Nitrogen

Phosphorus
Carbon Cycle:
Carbon is the key ingredient in all
living organisms
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



Carbon found:
In atmosphere: CO2 gas
In oceans: dissolved CO2
On Land: in organisms, rocks,
soil
 Underground: coal,
petroleum, Calcium
Carbonate
Don’t copy next slides, review
4 groups of organic compounds found in living things:
1. Carbohydrates: Living things use carbs as main source of
energy.
 Sugar and starch molecules
 made of H and O
 animals- use in liver and muscles
 plants-for food and cellulose
2. Lipids: can be used to
store energy. Makes
biological membranes of
cells and waterproof
coverings.
 fats, oils, waxes
 made of C and H atoms
Cell Membrane
3. Nucleic Acids: store and
transmit hereditary
information
 2 kinds (RNA, DNA)
 made of H,O,N,C,P
atoms
RNA strand
4. Proteins: control rate of reactions, regulate cell
processes, form bone and muscles, transport
substances in/out of cells or fight disease.
 made of C,H,O atoms
 made of amino acids (compounds)
Amino Acid
Chain
Protein: made of amino
acid chains folded up
CO2 released into the
atmosphere by:
 volcanic activity
 respiration- when
consumers exhale
 burning of fossil fuels
 decomposition of
organic matter
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Terrestrial plants-remove CO2 from the
atmosphere
Aquatic plants- remove CO2 from the water
Producers-convert CO2 into Carbs (Glucose)
“food”
Consumers-carry out cellular respiration
breaking down glucose into CO2
Nitrogen Cycle:
 Organisms need nitrogen to
make amino acids and build
proteins
 Nitrogen Gas (N2) is 78% of
the Earth’s atmosphere
 Can’t be absorbed directly
 Cacteria convert N2 into
compounds for use:
 Nitrogen Fixation- bacteria
living in soil, water or roots
of plants (legumes/bean
plants) convert N2 into
ammonia
Nitrification- 2-step process
NH3 -> NO2 -> NO3
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1.NH3 Ammonia in soil is
converted by bacteria to
Nitrite ions (NO2) but is
toxic to plants
2. Then it is converted to
Nitrate ions (NO3) which is
taken up by plants
3. Plants eaten by consumers
and reuse N to make
proteins
4. Decomposers break down
dead and return ammonia
(NH3) to the soil
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Denitrification- other bacteria convert
nitrates into N2 (gas) to be released
into the atmosphere again
Phosphorus Cycle:
Phosphorus is nutrient
for plants and animals
which forms DNA and
RNA
Does not enter
atmosphere like C,N,O
Found in land, rock,
soil and ocean sediments
How it works:
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1. Phosphorus in
inorganic phosphate
form
2. Released by
weathering/wind
3. Dissolved in soil and
water
4. Taken up by plant
roots in land and
water
5. Plants bind into
organic compounds to
move through food
web
*Limiting factor for plants
Limiting nutrient- when an ecosystem is limited by a single nutrient
that is scarce of cycles slowly
 Consumers get phosphorus by eating producers/animals
 Animal wastes and decay of dead organisms return
phosphorus to soil and water
 Guano- manure of fish eating birds