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Energy Flow and Matter
All living things need energy and food (matter).
Food is used for a variety of things i.e. manufacturing of new cells and to repair or
replace worn-out parts.
Energy is needed as a fuel to power all the required life processes, such as
respiration, growth, movement, excretion and reproduction.
Since energy is always being used up by plants and animals we have to have ways
to replace it. The sun is able to replace the energy through photosynthesis.
Photosynthesis
Producers (plants) use photosynthesis to obtain their food and energy.
This is the equation for photosynthesis:
12 H2 0+6 CO2 +sunlight energy=C6 H12 O6+6 H2 0+ O2
Cellular respiration
Consumers (animals and other organsims) use celluar respiration to obtain their
energy
Stored energy from plants and animals is released
During this reaction energy is produced. This energy is used by consumers
The chemical equation for cellular respiration is shown below:
C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy
Does this formula look familiar to you? Where have you seen it before? What is
the relationship between photosynthesis and respiration?
Energy Through a Community
All energy ultimately comes from the Sun.
Producers store some of this energy in the foods they make during photosynthesis.
Herbivores eat producers and carnivores eat herbivores (or other carnivores) and so
on. In this way, the Sun's energy is passed along in the food chains.
However, a lot of energy is "lost" as heat which is unusable, along the way.
Sources of Energy
hydropower (energy from water) i.e. mactaquac dam
nuclear energy (point lepreau)
oil (colson cove)
coal (belldune) and petroleum
natural gas (courtney bay)
solar
biomass
geothermal
wind
tidal and wave
Information for this section found on teacher page “Energy Assignment Solutions”
Renewable vs. Non-renewable energy
Non-renewable resource (Exhaustible) - These are energy resources that we can
run out of or be used up
- Examples could be:
o Oil
o Gas
o Coal
o Nuclear Power (uranium)
- Positives for these types of resources are that they are efficient sources of
energy, meaning you can get a lot of energy out of burning a small
amount of these fossil fuels.
- Negatives for these types of resources are that the burning of all fossil
fuels leads to greenhouse gas emissions (dirty), and that their resources
can be used up.
Renewable Resources – These are resources that can be used up, but can also be
replaced or replenished. Meaning as you use the resource, you can also replace the
resources.
- Examples are:
o Wood from trees
o Biomass/Bioconversion for energy – using plants, garbage, and
other living materials for energy. Living material is broken down
using methanol to alcohols which can be used for energy.
- Positives for these types of energy are that their resources can be replaced
when used up.
- Negatives for this type of energy are that burning of wood and release of
gases caused by biomass can lead to emission/pollution. Biomass is also
very inefficient, meaning it takes a lot of living material to produce a
small amount of energy.
Inexhaustible Resources – These are resources that can never be used up, and
cannot be replaced as well.
- Examples are:
o The suns energy – Solar power
o Hydro Power – Power from Dams
o Tidal and Wave – Using the movement of tides for energy
o Geothermal – Earth’s natural heat (hot springs)
o Wind – Wind mill turbines
- Positives for these types of energy are that they have unlimited resources.
You can never use up the sun’s energy, there will always be water
current, and there will always be wind. Also, these types of energy
cause little to no emissions.
- Negatives for these types of energy are that they are very inefficient. It
takes too much conversion of the resource to produce too little energy.
Recycling Matter
Matter is recycled.
Each organism serves as food for another. Producers eat consumers, consumers
eat other consumers and decomposers feed on the dead and dying.
Therefore all of the nutrients (like carbon, hydrogen, oxygen and nitrogen) which
made up the organism recycle back into the environment.
Cycling of Materials
Energy and matter are recycled in an ecosystem in order for it to function.
Within this matter that is recycled are the key elements.
Each of these key elements is recycled in what is called a cycle. We have the
carbon cycle, water cycle, and nitrogen cycle.
The Water Cycle
Energy comes from the sun.
The water cycle has 3 processes:
Evaporation
Condenstation
Precipitation
The sun evaporates the water from ocean, rivers, lakes, soil and from the surface of
leaves into the atmosphere.
When the water vapor reaches the colder air of the atomosphere is condenses back
into liquid water and is stored in the clouds.
When the clouds become filled with this liquid water it is returned to earth as
precipitation (rain, sleet, snow, hail etc). This water collects in rivers, lakes,
oceans or is absorbed into the soil.
The process is then able to begin again.
The Carbon Cycle
Carbon enters the ecosystem through the atmosphere as CO2.
Producers (plants) absorb the CO2 during photosynthesis.
Consumers eat the producers and obtain carbon from them it is then released back
in the atmosphere during cellular respiration.
When animals and plants die and are decomposing, decomposers release the CO2
back into the atmosphere as well through cellular respiration. The remaining
carbon from the dead and decaying organsims is placed into the soil.
Carbon can also be produced by the burning of wood and fossil fuels through
combustion and be released into the atmosphere.
The Nitrogen Cycle
All organisms require nitrogen, however only nitrogen fixing bacteria are able to
use nitrogen gas directly.
Nitrogen fixing bacteria are able to take nitrogen from the atmosphere and
transform it into ammonia.
Plants obtain ammonia through the soil.
Animals obtain ammonia from eating plants.
As plants and animals die and decompose the nitrogen they contain in their
proteins is returned to the soil or water and the bacteria can break it down into
nitrate or nitrites, which is returned back to the atmosphere.
Ecosystem Succession
How Ecosystems Change
We have looked at energy flow in the system and cycling of materials, now we will
look at how ecosystems change. Ecosystems undergo succession which is the
regular pattern of changes over time in the types of species in a community.
The process may take hundreds or thousands of years.
The final stable community that forms if the land is left undisturbed is called the
climax community.
Primary Succession
When succession occurs in areas where no ecosystem existed before. Ex: Islands
created by volcanic eruptions and areas exposed when a glacier retreats. Primary
succession is slower because it begins where there is no soil.
pioneer species = the first species of plant, animal or decomposer to inhabit a
piece of land, water etc
these species are joined by other organisms and then these organisms are replaced
with other species as the community becomes more mature.
Secondary Succession
- occurs where an ecosystem previously exsisted.
i.e. areas burned by fire that have regrown, farmland that has been abandoned
being used for farms again