Chapter 2.3
Cycling of Matter
Notes
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_____________: a series of events that occur in a regular __________________________________
______________: anything that takes up ________________ and has ___________________.
___________________: a chemical substance that an organism must obtain from its environment to sustain life and to
undergo life processes.
o Where do nutrients come from? _______________! The bodies (matter) of all organisms are built from water
and nutrients such as _______________, _______________, and ________________________
__________________________________: any molecule that contains the element carbon
Cycles in the Biosphere
• A constant supply of usable ______________________ is needed to support the functions of an ecosystem. Energy
_____________________ be cycled- energy has an entrance point and an exit point in an ecosystem.
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The law of conservation of mass states that matter is not ___________ or ________________, it merely
____________________________. So… the same amount of matter has existed since the beginning of time. Matter
has not been added or lost, but has been cycled over and over.
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In most ecosystems, plants obtain nutrients, in the form of _____________________ and __________________, from
the ________, _________, or _____________. Plants convert some elements and compounds into
____________________ that they use. The nutrients flow through organisms in the ecosystem. As organisms die,
________________ return the nutrients to the cycle ________________________________________.
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__________________________________________: the exchange of matter through the biosphere. Just like the name
sounds the cycle involves living organisms (________), geological processes (_________), and chemical processes
(chemical). The cycling of nutrients in the biosphere involves both matter in living organisms and physical processes
found in the environment such as weathering. Weathering breaks down large rocks into particles that become part of
the soil used by plants and other organisms.
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There are 4 kinds of biogeochemical cycles we will discuss
o _______________________________
o _______________________________
o _______________________________
o _______________________________
The water cycle use the diagram found here to follow the water cycle
Key terms:
• Evaporation- when liquid water becomes
____________________________. Water evaporates
off of bodies of water such as ponds, lakes, streams,
rivers, the ocean, etc.
• Condensation- when water vapor cools and forms
droplets. In the atmosphere, ____________________
_____________________________________________
_____________________________________________
• Precipitation- rain, snow, sleet, hail, mist, etc. This is
how water gets back to the Earth’s surface.
• Transpiration_____________________________________________
_____________________________________________
Why is the water cycle important? __________________________________________________________
______________________________________________________________________________________
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Only ___________ of all available water on Earth is fresh
________________ of the available fresh water is ______________ in __________ and ______________. Living
things cannot use frozen water!
The carbon and oxygen cycles use the diagram below to understand the carbon and oxygen cycle
Key terms:
• Photosynthesis- the process by which plants and algae take
____________________ and water from the atmosphere and make
carbohydrates. They then release ________________ into the
atmosphere
• Respiration- takes place inside ______________ and is NOT the
same thing as breathing! It is the process by which plants, algae
and animals use _________________ to break down food and
release the energy in food. They then release _______________
into the atmosphere.
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Important facts about the carbon oxygen cycles
Carbon and oxygen make up molecules essential for
_______________. These include proteins, carbohydrates, fats,
and carbon dioxide
Carbon and oxygen are recycle relatively quickly through living
organisms (i.e. ____________________ and ___________________________)
Carbon enters a long-term cycle when organic matter (i.e. dead plants, animals and other organisms) is buried
underground. This buried organic matter forms __________________ in different forms- peat, coal, oil, or gas
deposits. The carbon in fossil fuels may remain, locked in the ground for millions of years. The carbon is released
from fossil fuels when they are burned, which adds __________________________ back into the atmosphere
Another way for carbon to enter a long-term cycle is in the form of _____________________________. Calcium
carbonate is found in the shells of plankton (microscopic animals and algae found floating in water) and in the shells of
larger animals such as coral, clams, and oysters. When these organisms die, they fall to the bottom of the ocean floor
and create vast deposits of _________________ rock (calcium carbonate). The ____________________ and
__________________ remain locked in the limestone until weathering and erosion release them into the cycle.
The nitrogen cycle use the diagram below to understand the nitrogen cycle
Key terms:
• Nitrogen fixation- the process by which nitrogen gas in the
atmosphere (which plants cannot use) is converted into a form
that plants can use. _______________________ that live in
water, soil, or the roots of some plants are responsible for
nitrogen fixation.
• Denitrification- the process by which some bacteria found in soil
convert ______________________ (the form of nitrogen plants
can use) into nitrogen gas, which returns to the atmosphere.
• Excretion- the process by which animals get rid of wastes
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Important facts about the nitrogen cycle
• Nitrogen is an element found in proteins. Because organisms are
made of proteins, organisms need nitrogen.
• Most of the nitrogen found on Earth is found in the atmosphere
in the form of ____________________.
• Some nitrogen can be fixed when the energy from
______________________ changes nitrogen gas to nitrates.
A lot of extra nitrogen is added to ecosystems when farmers, homeowners, etc. add ________________ to crops and
lawns.
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Nitrogen enters the food web when _______________ absorb nitrogen compounds from the soil and convert them into
___________________. Consumers get nitrogen by eating plants or animals that contain nitrogen. They reuse the
nitrogen to make their own proteins.
The amount of nitrogen in a food web ________________ the growth of producers because the supply of nitrogen
depends on the amount of nitrogen fixed by bacteria.
Nitrogen is returned to the soil in different ways
o When organisms die, decomposers transform the nitrogen in their proteins and other compounds into
___________________, a nitrogen-containing compound. Soil organisms then convert the ammonia into
nitrogen compounds plants can use.
o When organisms excrete wastes, the nitrogen returns to the water or soil and is reused by plants.
The phosphorous cycle use the diagram below to understand the phosphorous cycle
Important facts about the phosphorous cycle
• Phosphorous is an element that is essential for the
_______________ and ____________________ of
organisms
• Phosphorous can be found in a compounds called
phosphates
• There are two cycles of phosphorous
o _____________________________:
phosphates, dissolved in water, release
their phosphorous. The phosphorous is
cycled from soil to producers to
consumers. When organisms die or
produce waste products,
__________________ return the
phosphorous to the soil where it can be
used again.
o _____________________________: weathering or erosion of rocks that contain phosphorous slowly adds
phosphorous to the cycle.
• Phosphorous can move from the short-term cycle to the long-term cycle through _____________________________
and _____________________________ (the process of forming rocks)
• Phosphorous can limit the growth of producers because phosphates (remember, phosphorous can be found in
phosphates) might be present in soil and water only in small amounts.