Section 13-5
“Cycles”
Write everything
that is underlined
13.5 Cycling of Matter
KEY CONCEPT:
Matter cycles in and out of an
ecosystem.
13.5 Cycling of Matter
I. The Water Cycle
1. The hydrologic, or water cycle is the
circular pathway of water on Earth.
precipitation
condensation
transpiration
evaporation
surface
runoff
lake
groundwater
water storage
in ocean
13.5 Cycling of Matter
2. Key terms for the water cycle:
a. Precipitation: moisture that falls to the
ground (rain, snow, sleet, hail)
b. Evaporation: changing from liquid to
gas (water to water vapor)
c. Transpiration: plants give off water
vapor from their leaves to the air
d. Condensation: changing from gas to a
liquid (little water droplets form on the
outside of a cold glass of lemonade - that’s
condensation)
13.5 Cycling of Matter
II. Oxygen Cycle:
1. Plants make food by photosynthesis
–They use carbon dioxide (CO2) to
make oxygen (O2)
2. Animals breathe out carbon by
respiration
–They use oxygen (O2) and breathe
out carbon dioxide (CO2)
–By the way … humans are animals
too
13.5 Cycling of Matter
Example: Oxygen Cycle:
oxygen
photosynthesis
respiration
carbon
dioxide
13.5 Cycling of Matter
Activity
• Draw, label, color, and explain the water cycle and
oxygen cycles on a sheet of paper.
• Page 413 figure 13.12 & 13.13
• Due tomorrow
13.5 Cycling of Matter
III. Carbon Cycle
1. Carbon is the building block of
life.
a. The carbon cycle moves carbon
from the atmosphere, through the
food web, and returns to the
atmosphere.
b. Carbon is emitted by the burning
of fossil fuels (like oil, gasoline,
and coal)
13.5 Cycling of Matter
Carbon Cycle: notice photosynthesis and
respiration are back … they both involve CO2
(now we’re looking at the C for carbon)
carbon
dioxide
in air combustion
respiration
photosynthesis
respiration
decomposition
of organisms
fossil fuels
photosynthesis
carbon dioxide
dissolved in water
13.5 Cycling of Matter
IV. The Nitrogen Cycle
1. The nitrogen cycle mostly takes place underground.
2. Some bacteria convert gaseous nitrogen into ammonia
through a process called nitrogen fixation.
– Some nitrogenfixing bacteria
live in
nodules on the
roots of plants;
others live
freely in
the soil.
nitrogen in
atmosphere
animals
plant
nitrates
nitrogen-fixing
bacteria in
decomposers
nitrifying
roots
bacteria
ammonification
nitrites
nitrogen-fixing
ammonium
bacteria in soil
nitrifying
denitrifying
bacteria
bacteria
13.5 Cycling of Matter
3. Ammonia released into the soil is transformed
into ammonium.
4. Nitrifying bacteria change the ammonium
into nitrate.
– Nitrogen moves
through the
food
web and
returns
to the soil
during
decomposition.
nitrogen in
atmosphere
animals
plant
nitrogen-fixing
bacteria in
decomposers
roots
ammonification
nitrogen-fixing
ammonium
bacteria in soil
nitrifying
bacteria
nitrates
nitrifying
bacteria
nitrites
denitrifying
bacteria
13.5 Cycling of Matter
V. Phosphate Cycle
1. Phosphate is released by the
weathering of rocks.
Phosphorus leaches
into groundwater
from the soil and
is locked in
plants
sediments.
b. Both mining and
agriculture add
phosphorus into
the environment.
a.
rain
geologic uplifting
weathering of
phosphate from rocks
runoff
animalsphosphate
phosphate in solution
in soil
leaching
decomposers
sedimentation
forms new rocks
13.5 Cycling of Matter
Activity
• Draw, label, color, and explain the Carbon and
Nitrogen cycles on a sheet of paper.
• Page 414-115 figure 13.14 & 13.15
• Due tomorrow
13.5 Cycling of Matter
Review Questions 13.5 Cycling of Matter
1. What is the key concept of this unit?
2. Define the key terms for the water cycle.
3. What do plants take in and then give out. What do
animals take in and give out?
4. How does the carbon cycle move carbon?
5. Where is carbon emitted?
6. Where does the nitrogen cycle take place
7. What are phosphates released by?