Transcript The cycling of matter in ecosystems

Warm Up
1. Why can’t a food chain have an infinite
number of links?
2. Why aren’t there large numbers of big
animals (top consumers) in an
ecosystem?
3. Name two processes that recycle water
in an ecosystem.
The Water Cycle
Condensation
Transpiration
Precipitation
Evaporation
Runoff
The Water Cycle
What you should know about the
Water Cycle
5 main physical processes:
1. Evaporation (ocean/lake  water vapor)
2. Condensation (water vapor  clouds)
3. Precipitation (clouds  rain/snow)
4. Transpiration (the process of water vapor
coming out of plant leaves)
5. Runoff (rivers, streams)
You need to be able to draw the water cycle as a
network.
Think and be ready to share:
1. What are some forms of carbon found on
earth or in the atmosphere?
2. Name two processes that recycle carbon
in an ecosystem.
Why is Carbon important?
Glucose
• Required for all
organisms on earth
• Needed to make
DNA, proteins, fats,
sugars
Cell
membranes
are composed
of lipids
The Carbon Cycle
Photosynthesis and respiration
Photosynthesis
6CO2 + 6H2O
Carbon
dioxide
sunlight
Water
C6H12O6 + 6O2
Sugar
Oxygen
Respiration
C6H12O6 + 6O2
Sugar
Oxygen
6CO2 + 6H2O
Carbon
dioxide
Water
Photosynthesis and Respiration
• Note how the OUTPUT of photosynthesis
is the same as the INPUT of respiration
• Note how the OUTPUT of respiration is
the same as the INPUT of photosynthesis
• Matter CYCLES back and forth between
photosynthesis and respiration.
What happens to plants that aren’t
eaten by consumers?
What is the role of decomposers?
Small organisms
Worms, insects
Microorganisms
Fungi, bacteria
Decomposers
• Small organisms (worms, insects) break
down waste and dead organisms into
smaller parts.
• Microorganisms (bacteria, fungi) digest
the smaller parts into chemical forms that
can be used by plants.
• Ex: CO2
Decomposers in the Carbon Cycle
The decomposers
take waste and
turn it back into a
form usable by the
producers (CO2).
The producers
then release the
carbon dioxide
back into the
atmosphere.
What you need to know about the
Carbon Cycle
The role of…
1. Photosynthesis
2. Respiration
3. Decomposers
4. Combustion, human impact
You need to be able to draw the carbon
cycle as a network. Let’s practice.
Nitrogen Cycle
All living organisms must have nitrogen to live
(make DNA and proteins.)
Atmospheric nitrogen (N2) cannot be used as a
nitrogen source by plants or animals.
Nitrogen exists in other chemical forms:
– Ammonia (NH3)
– Nitrites (NO2) and Nitrates (NO3)
– Other molecules in waste (urine, dung,
corpses)
Draw a network to summarize:
1.
2.
3.
4.
5.
6.
Plants (autotrophs) get their nitrogen from nitrites (NO2) ammonia
(NH3) and nitrates (NO3) in the soil.
Animals (heterotrophs) get their nitrogen from eating plants and
other animals.
Some special plants and bacteria can “FIX” atmospheric nitrogen
(N2) and turn it into nitrites (NO2) ammonia (NH3) and nitrates
(NO3)
Some Bacteria can produce atmospheric nitrogen (N2) from
ammonia (NH3)
Animals produce waste containing molecules with nitrites (NO2)
ammonia (NH3) and nitrates (NO3) (urine, corpses, feces)
Decomposers can turn the nitrogen in dead organisms into nitrites
(NO2) ammonia (NH3) and nitrates (NO3)
The Nitrogen Cycle
Nitrites, nitrates
What’s important?
• You must be able to explain
that microscopic decomposers
(bacteria, fungi) function in
ecosystems to recycle carbon
and nitrogen.