Name: _______________
Date: _______________
Science 7
Unit A: Interactions and Ecosystems
2.4 Matter Cycles in Ecosystems
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Energy flows in ecosystems
o Can be demonstrated with food chains and food webs
Energy and matter are abiotic factors within ecosystems
o They are both required in ecosystems
Water and Carbon Cycles
 Matter makes up all living and non-living things on Earth
o That matter has been here for billions of years and is continuously
recycled
o Matter continuously moves from abiotic environments to biotic
environments and back to abiotic environments
 This movement of matter is referred to as a cycle
2.4 Matter Cycles in Ecosystems
Hills 2014
The Water Cycle
 3 main processes are responsible for the water cycle:
o Evaporation: liquid water is heated by the Sun and causes it to
change from a liquid to a gas
o Condensation: gaseous water condenses into clouds
o Precipitation: as a cloud cools, gaseous water turns to snow, rain, or
hail and falls back to Earth
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Water enters and exits the environment in many different ways
o Anything that burns fuel releases some water vapour as a product
into the atmosphere
o Living things put water vapour into the atmosphere anytime they
exhale
 H2O is a product of cellular respiration
o Animals need to consume water to live
o Plants need to consume water for photosynthesis
The Carbon Cycle
 Living things all contain Carbon
o Over millions of years, substances that contain carbon can become
fuels such as coal and natural gas
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2.4 Matter Cycles in Ecosystems


Hills 2014
Animals (cellular respiration) and industry (combustion) both add carbon
dioxide to the atmosphere
o Too much can be toxic to living creatures
Plants recycle the carbon dioxide to produce oxygen during
photosynthesis
o If a plant is harvested and burnt, CO2 is released back into the
environment
 Burning substances that contain carbon releases CO2 into
the environment
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