Transcript Biogeochemical Cycles

Biogeochemical Cycles
Mrs. Stewart
Honors Biology
CLE 3210.3.4 Describe the
events which occur during the
major biogeochemical cycles.
You will know you have
mastered this standard when:
You can predict how changes
in a biogeochemical cycle can
affect an ecosystem
Objectives:
• Analyze the flow of nutrients in each
biogeochemical cycle.
• Evaluate the impact that humans
have on the biogeochemical cycles.
Why do we recycle?
• Think – Pair - Share
What sustains life on
Earth?
• Solar
energy
• The
cycling of
matter,
energy &
nutrients
• Gravity
Two Secrets of Survival: Energy
Flow and Matter Recycle
• An
ecosystem
survives by a
combination
of energy
flow and
matter
recycling.
MATTER CYCLING IN
ECOSYSTEMS
• Nutrient Cycles: Global Recycling
– Global Cycles recycle nutrients through
the earth’s air, land, water, and living
organisms.
– Nutrients - the elements and compounds
that organisms need to live, grow, and
reproduce.
Macromolecule Review
• What element does every organic
organism contain? Carbon
• What are the 5 major elements that
create all the macromolecules?
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorous
Think – Pair – Share
• What would happen to these elements
if they were only capable of being
used once?
– Think about every time an organism is
created and/or destroyed
They would begin
disappearing (dwindling in
supply)
– like fossil fuels
Biogeochemical Cycles
– These are just illustrations or
representations to show how substances
move through air, water, soil, rock and
living organisms.
Decomposition
•Decomposers:
– ultimately responsible for recycling of
chemical nutrients
– releasing the nutrients in detritus
•This makes nutrients available
again to the autotrophs in the
ecosystem
Recycling
• What nutrients get recycled?
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Carbon Dioxide
Oxygen
Water
Carbon
Nitrogen
Phosphorous
Water Cycle
Movement of Water
• Three important processes:
1. Evaporation – adds water as vapor to
atmosphere (heat)
a. Bodies of water, soil, animal bodies, etc.
2. Transpiration – water evaporates from
the leaves of plants
3. Precipitation – water released from the
atmosphere (temperature, air pressure)
a. Rain, snow, sleet, hail or fog
Water Cycle
Think-pair-share
• What human activities effect the water
cycle?
– What do we do as humans that could
have positive or negative effects on this
cycle
– 2 minutes
Effects of Human Activities
on Water Cycle
• We alter the water cycle by:
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Withdrawing large amounts of freshwater.
Clearing vegetation and eroding soils.
Polluting surface and underground water.
Contributing to climate change.
• How do these changes affect the
surrounding ecosystems?
Objectives:
• Analyze the flow of nutrients in each
biogeochemical cycle.
• Evaluate the impact that humans
have on the biogeochemical cycles.
Carbon Cycle
Photosynthesis vs Cellular
Respiration
• Photosynthesis
absorbs CO2 from
the
atmosphere/biosp
here and releases
O2
• Cellular respiration
absorbs O2 from
the
atmosphere/biosp
Carbon is found in 5 major
places:
1.
2.
3.
4.
5.
Living and dead organisms
Carbon Dioxide (CO2) in atmosphere
Organic matter in the soil
Fossil fuels and rock deposits
Oceans – dissolved CO2 and shells
Do these plants contain
Carbon?
What happens to the
carbon now?
Where is the carbon?
Think-pair-share
• What human activities effect the
Carbon-Oxygen cycle?
– What do we do as humans that could
have positive or negative effects on this
cycle
– 2 minutes
Effects of Human Activities
on Carbon Cycle
• We alter the
carbon cycle by
adding excess
CO2 to the
atmosphere
through:
– Burning fossil
fuels.
– Clearing
vegetation
faster than it is
replaced.
• How do those changes affect the
surrounding ecosystems?
Objectives:
• Analyze the flow of nutrients in each
biogeochemical cycle.
• Evaluate the impact that humans
have on the biogeochemical cycles.
Nitrogen Cycle
Nitrogen Uses:
• Proteins
– Enzymes, skin,
muscles, etc.
• Nucleic Acids
– DNA
– RNA
Forms of Nitrogen
• Nitrogen is found in many forms in the
atmosphere / ecosystem
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N2 = nitrogen gas (79% of atmosphere)
N2O = nitrous oxide
NH3 = ammonia
NH4 = ammonium
NO3 = nitrate
NO2 = nitrite
Nitrogen Fixation
• Converting N2 gas to nitrate (only
usable form of nitrogen for most plants)
• 2 types:
– Natural = lightning, fires and bacteria
– Human = fossil fuel combustion, fertilizer
manufacturing
Nitrogen-fixing bacteria
• bacteria that transform Nitrogen gas
into a usable form (Nitrate)
– Live in the soil
– May live in the swellings on the roots of
some plants (ex. Beans, peas, clover)
• These plants provide sugars for the bacteria,
and the bacteria provide usable nitrogen.
Recycling Nitrogen
• Where is Nitrogen
found?
– Dead organisms (as
proteins & nucleic
acids)
– Urine & dung
• Decomposers: break
down and release
Nitrogen as NH3
(ammonia)
Nitrogen Processes
• Ammonification – converting NH3
(ammonia) to NH4 (ammonium)
• Nitrification – converting NH4
(ammonium) into NO2 (nitrite) or NO3
(nitrates)
• Denitrification – anaerobic bacteria
break down NO3 (nitrates) and release
N2 (nitrogen gas) into the atmosphere
Nitrogen Sources:
• Plants = Nitrates from the soil
– Use to form proteins
• Animals = eating plants/organisms and
digesting the proteins and nucleic
acids
• Humans = have doubled the amount
of fixed N2 in the atmosphere in the
last 100 years.
– HOW?
Too much of a good thing?
• Too much nitrogen in aquatic
ecosystems results in:
•Eutrophication = excess
nutrients stimulate plant growth
(algal blooms); when these
plants die, decomposers use
up the available oxygen
during decomposition.
Eutrophication
Nitrogen Cycle
Think-pair-share
• What human activities effect the
Nitrogen cycle?
– What do we do as humans that could
have positive or negative effects on this
cycle
– 2 minutes
Effects of Human Activities
on the Nitrogen Cycle
• We alter the nitrogen cycle by:
– Adding gases that contribute to acid rain.
– Adding nitrous oxide to the atmosphere
through farming practices which can
warm the atmosphere and deplete
ozone.
– Contaminating ground water from nitrate
ions in inorganic fertilizers.
– Releasing nitrogen into the troposphere
through deforestation.
Effects of Human Activities
on the Nitrogen Cycle
• Human
activities such
as production
of fertilizers now
fix more
nitrogen than
all natural
sources
combined.
How does this affect the
surrounding ecosystems?
• Acid rain
• creation of ground level
ozone
• groundwater contamination
• eutrophication.
•Exploring the Nitrogen Cycle
Activity
Objectives:
• Analyze the flow of nutrients in each
biogeochemical cycle.
• Evaluate the impact that humans
have on the biogeochemical cycles.
Phosphorus Cycle
Overview
• Movement of phosphorus from the
environment, to organisms, and back
to the environment
• Slow process
• Normally does not occur in
atmosphere because phosphorus
rarely occurs as a gas
Phosphorus Uses:
• Essential material for animals
– Form bones, teeth, molecules (DNA/RNA)
Where do organisms get
phosphorus?
• Plants = absorb from soil and water
• Animals = eating plants & other organisms
Cycle
• Rocks erode, and small amounts of phosphorus
dissolve as phosphate PO4 3-, in soil and water
• Excreted in wastes from organisms
• Released by decomposers from dead
organisms
• Plants absorb from soil and water, through
roots
• Animals eat plants/other organisms
• Some in fertilizers and applied to fields/crops
• Washes off into streams, groundwater and
soil
Phosphorus Cycle
Think-pair-share
• What human activities effect the
Phosphorus cycle?
– What do we do as humans that could
have positive or negative effects on this
cycle
– 3 minutes
Effects of Human Activities
on the Phosphorous Cycle
• We remove large amounts of
phosphate from the earth to make
fertilizer.
• We reduce phosphorous in tropical
soils by clearing forests.
• We add excess phosphates to aquatic
systems from runoff of animal wastes
and fertilizers.
What determines
population size?
Environment vs Habitat
• Many species can
survive in more than
one environment.
• But each species
has its “home” or
habitat.
– Fish may be able to
live in fish tanks, but
would rather live in
the wild
What do organisms need to
survive?
• Basic requirements
for survival include:
– Food
– Water
– Shelter
Competition
• An important
aspect of the
struggle for survival
involves
competition for
limited resources
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Food
Water
Shelter
Sunlight
Limiting Factors
• Limiting factors are
factors that affect
the population size
of a species in a
specific
environment.
• They can be abiotic
or biotic.
Predator – Prey relationship
• Predators are a
biotic limiting factor.
• They control
population size by
feeding on prey.
• There is a delicate
balance that needs
to be maintained.
Carrying Capacity
• When all the limiting
factors are
considered
together we can
determine the
maximum number
of organisms that
can survive in an
area.
How do we determine the
Carrying Capacity of a Species?
• All limiting factors
must be taken into
consideration.
• It is very difficult to
determine the
actual carrying
capacity.
The Lesson of the Kaibab Deer
• Purpose:
– to graph data on the
Kaibab deer population
of Arizona from
1905~1939
– to analyze the methods
responsible for the
changes in the deer
population
– to propose a
management plan for
the Kaibab deer
population
How Many Bears??
Kaibab Forest: North Rim of the
Grand Canyon
Key Idea
• All organisms have
the ability to
produce
populations of
unlimited size
• But their
environment keeps
their numbers in
check.
• THINK-PAIR-SHARE
– How?
– List examples of
limiting factors.
– 3 minutes