Carbon Cycle
Key points
Carbon Cycle
geos.ed.ac.uk
How Carbon moves
• Atmosphere to plants
– Photosynthesis: CO2 to plant food
– Carbon dioxide + Water + Light energy → Glucose +
Oxygen
– 6 CO2 + 6 H2O → C6H12O6 + 6 O2
• Plants to animals
– Food chain: producers to consumers
• Plants and Animals to ground (Soil)
– Died and then decompose
– Some gets buried miles underground and turns into
fossil fuels in millions and millions of years.
Continue on how Carbon moves
• Living things to atmosphere
– Respiration: animal and plants get rid of CO2 by
exhaling
• Humans to the atmosphere
– Burning fossil fuels
– Each year 5 ½ billion tons of C is released…equals 100
million adult African elephants!
Continue on how Carbon moves
• Atmosphere to Ocean
– Diffusion: ocean soak it up
– Marine animals use it to build their skeletons and
shells
• Marine animals to ocean floor
– Die and drop to the floor
– Eventually they form into limestone
Carbon Cycle Question
• We enjoy the taste of an apple because it is
sweet. From where did the apple tree get the
carbon to make sugar?
– A.
– B.
– C.
– D.
air
water
soil
nitrate fertilizer
Carbon Cycle Question
• The most abundant element in a wooden stick
is carbon. Where did the carbon come from?
– A.
– B.
– C.
– D.
water
air
soil
fertilizer
Carbon Cycle Question
• Where do animals get the carbon found in
their bodies?
– A.
– B.
– C.
– D.
from the air
from eating food
from the soil
from vitamins and minerals
Carbon Cycle Question
• For millions of years the carbon cycle has been in
balance. Climatologists are concerned because
data indicates the amount of carbon in the air is
increasing. Which theory best explains this loss
of atmospheric balance?
– A. CFAs have created a hole in the ozone.
– B. Society has increased the burning of fossil fuels.
– C. Environmentalists have increased the size of rain
forests.
– D. Our society has recognized the danger of nuclear
fission.
Carbon Cycle Question
• If the carbon dioxide in the atmosphere
increases due to human activities, what do
scientists predict will be the result?
– A.
– B.
– C.
– D.
increased cases of sunburn
warmer temperatures
increased incidence of earthquakes
more snowfall in the winter
Importance of Carbon
• Building block for life
– Forms fossil fuels
– Is used in complex molecules, such as DNA and
RNA, to control genetic reproduction in
organisms.
• RNA: to read the genetic information found in DNA and
to produce specific organic molecules used in the
development and functioning of cells. It is a copy of a
portion of DNA.
• DNA: Coding for genetics and direct the development
and functioning of cells.
Nitrogen
Cycle
Key Points
Nitrogen Cycle
bioh.wikispaces.com
Importance of Nitrogen
 Allows
plants and animals to make amino
acids, proteins and DNA


Amino acids: use to make proteins
Proteins: made of C, H, N, and other
elements, involved in almost all cell
functions
 Forms:
antibodies, contractile-movement,
enzymes, storage, structural support

DNA: genetic coding to direct the
development and functions of cells.
How Nitrogen Moves

Move from atmosphere to Plants




Plants to Animals


Food Chain: Producers to consumers
Plants and animals to soil



Fire, lightning, and nitrogen-fixing bacteria
Changes it from N2 to the form which plants can use:
ammonium ion (NH4+) and nitrate (NO3-)
Bacteria live in the soil and on the roots of plants, which
then provides nitrogen to the plants
Animal waste
Decay of organisms
Plants and animals to atmosphere

Decay of organisms
Human impact on the
Nitrogen Cycle
 Humans
add to much nitrogen which off
balances the cycle

Nitrogen-rich fertilizer and livestock waste
 Affect:


Increase nitrate (form of nitrogen) causes
plants to grow fast until they use up the
supply and die
Increase in plants = increase in consumers
and when the plants all die so do the
consumers
Nitrogen Cycle Question
 Which
letters on the cycle shows where
nitrogen is being “fixed” into a useable
form for plants?




A.
B.
C.
D.
A, D
B, C
C, D
A, B
Nitrogen Cycle Question
 How
do plants get the nitrogen they
require for growth?




A. the process of photosynthesis creates
nitrogen from sugar
B. by absorbing it from holes in their leaves
and combining it with oxygen
C. a symbiotic relationship with bacteria
that “fixes” nitrogen in the roots
D. nitrogen from the air attaches itself to
the stem and leaves of plants.
Nitrogen Cycle Question
 Which
of the following best explains why
animal manure can be used as a fertilizer
for crops and gardens? The plant uses
the




A. carbon from the dead plant matter to
make sugar
B. nitrogen to make proteins and DNA
C. oxygen for cellular respiration
D. hydrogen to form sugars
Carbon Cycle Question
 Which
place on the nitrogen cycle shows
nitrogen in its LEAST useable form?




A.
B.
C.
D.
A
B
C
D