Transcript Ecosystems: Cycling of Matter

Ecosystems:
Cycling of Matter
SC STANDARD B-6.4: EXEMPLIFY THE ROLE
OF ORGANISMS IN THE GEOCHEMICAL
CYCLES
 CN: p. NB
 Topic: Ecosystem Cycles
 EQ: How do nutrients move through biotic &
abiotic factors in ecosystems?
The Water Cycle
 Water vapor condenses to its
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liquid phase in clouds and
falls to Earth as precipitation.
Some of this water percolates
through the ground and is
added to ground water.
Other water runs off the
surface and is added to bodies
of water
Water evaporates from plants
in a process called
transpiration.
Warm water evaporates to
water vapor, warm air rises.
The Carbon Cycle
 Plants use CO² from air
and use it to make
organic molecules
(photosynthesis) and in
the process release O²
 Herbivores eat the plants
for energy and convert
the organic molecules
into ATP releasing CO²
The Carbon Cycle
The Carbon Cycle-2
 The O² released during photosynthesis is used by
many organisms to break down the organic molecules
releasing ATP and CO² (cellular respiration)
 Carbon is also released through combustion (burning
of organic molecules) using O²
 Carbon also released from swamps, animals, and is in
volcanic eruptions
The Nitrogen Cycle
 Nitrogen must be cycled through an ecosystem so that
N is available for organisms to make proteins and
nucleic acids.
 Earth’s atmosphere is about 78% N² gas
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Most organisms cannot directly use N² gas
Some bacteria have enzymes that allow them to break the triple
bond in N² (N≡N) & then form NH³ (ammonia). This process
is called nitrogen fixation
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Some nitrogen also fixed by lightning
The Nitrogen Cycle-2
The Nitrogen Cycle-3
Assimilation is the process by which plants absorb
nitrogen
 Ammonification is the process by which nitrogen from
animal waste or decaying bodies (in proteins or nucleic
acids) is turned back to NH³ by bacteria.
The Nitrogen Cycle - 4
 Nitrification: bacteria perform:
NH³  nitrite  nitrates (NO³)
 Denitrifcation: other bacteria take
NO³  N² gas returning nitrogen to the atmosphere
 Legumes have nodules
on their roots which
contain the nitrogen
fixing bacteria
Phosphorus Cycle
 Phosphorus (P) is important part of ATP, RNA, & DNA
molecules
 P is least common, does not enter atmosphere
 P is found in soil & rock as calcium phosphate
 When rain falls it dissolves releasing phosphate
 Phosphate can be absorbed by plant roots  enters
food chain
 Makes its way to oceans
Used by marine organisms or deposited on ocean
floor
Phosphorus Cycle
 http://bcs.whfreeman.com/thelifewire/content/chp
58/5802001.html
 Analyzing Data
 Page 79 of textbook
 NB page : answer questions 1-4
 Draw, color, & label:
 Water Cycle: p. 135 NB p. 75 textbook
 Carbon Cycle: p. 136 NB p. 77 textbook
 Nitrogen Cycle: p. 137 NB p. 78 textbook
 Phosphorus Cycle: p. 138 NB p.79 textbook