Science 9 - Energy Flow in Ecosystems

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ENERGY IN ECOSYSTEMS
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Food Chains

• A linear relationship demonstrating the flow of
  energy organic matter in an ecosystem

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All energy in an ecosystem comes from the sun
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The Sun

• The sun produces energy (heat, light, and
  radiation) through fusion.

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The Sun

• Harmful energy components are filtered by
  Earths atmosphere and magnetic field

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The Ozone Layer
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September 1979 Ozone Levels
http//ozonewatch.gsfc.nasa.gov/monthly/climatolog
y_09.html
August 2009 Ozone Levels
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The Ozone Layer
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The Sun
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The Sun

• Provides energy for Earths BIOSPHERE the
  combined ecosystems (living parts) of our planet,
  the location of life

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The Sun

• Majority of Suns energy reach our planet and
  interacts with the Earths physical components
• Atmosphere
• Lithosphere
• Hydrosphere

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The Sun

• Drives our planets CLIMATE by controlling
  temperature, wind, and amounts of precipitation

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The Sun Wind Patterns
NOW A CLIP
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Albedo Effect

• The tendency of an object to reflect light,
  instead of absorbing it.
• Albedo is the percentage of light reflected by
  any object

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LOW ALBEDO
HIGH ALBEDO
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Albedo Effect

• Notice anything common about the locations of our
  planet with HIGH ALBEDO

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Albedo Effect

• HIGH ALBEDO
• Objects which are light coloured such as snow,
  sand, clouds, and areas without trees
• Reflect light, meaning they do not absorb
  light/heat.

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Albedo Effect

• LOW ALBEDO
• Objects which are dark coloured such as asphalt,
  dark soil, and forests.
• Absorb light, release infared radiation (heat)
• Bodies of water also absorb light

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Albedo Effect Global Warming?
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Greenhouse Effect

• A natural layer of greenhouse gases insulate the
  earth
• They trap the heat released by the Earth
• Helps maintain a global temperature which
  maintains life

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Greenhouse Effect

• Greenhouse effect is NOT global warming

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ENERGY FLOW IN ECOSYSTEMS
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Food Chains

• A linear relationship demonstrating the flow of
  energy organic matter in an ecosystem
• But the animal relationships are much more
  complex in ecosystems.

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Food Chains Energy

• Arrows point in the direction of energy flow
• 1st organism is always the producer
• Primary Consumer 2nd organism is the consumer
  that eats the producer
• Secondary Consumer 3rd organism is the consumer
  that eats the 1st level consumer
• And so on....

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Food Webs

• In reality, ecosystems are very complex having
  many interweaving food chains which form a food
  web.

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Trophic Levels

• Trophic level describes the position of the
  organism in relation to how it gets its nutrients
  energy
• Literally means feeding level
• Organisms eating the same food would be at the
  same feeding level

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4th Trophic Level
3rd Trophic Level
2nd Trophic Level
1st Trophic Level
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Note how energy flows in one direction but how
the matter all ends up in the detrivores and
decomposers eventually. For this reason,
decomposers and detrivores belong to all trophic
levels except the first one.
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Thermodynamics

• Thermodynamics is the study of energy and energy
  change
• Types of Energy?
• 1st Law of Thermodynamics Energy is never
  created or destroyed, but only changes form.

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Thermodynamics

• 2nd Law of Thermodynamics every time energy
  changes form, some energy is lost in the form of
  heat.
• This holds true for ecosystems (food chains/webs)

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Energy Loss in Ecosystems

• Only about 10 of energy gets passed through each
  step of a food chain
• 90 of energy is lost at each step to carry out
  life process, lost as heat or through feces

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Energy Loss in Ecosystems

• How much energy would be available to the rabbit
  and fox?

?
1000 KJ
?
100 KJ
10 KJ
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Energy Loss in Ecosystems

• Question suppose 10 000 KJ of energy are
  available at the level of the grasses. What is
  the total number of energy units lost by the time
  energy reaches the coyote?
• Answer 9990 KJ

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Energy Pyramid

• Energy pyramids illustrated how much energy is
  available at a given trophic level.
• Allows you to understand there are less
  consumers, as you move up a food web.

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Energy Pyramid
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Pyramid of Numbers

• Provide information at the number of individuals
  at each trophic level in an ecosystem
• Are not always pyramid shaped
• Often depends on the sized of organisms involved

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Pyramid of Numbers

• Typical pyramid for involving carnivores

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Pyramid of Numbers

• Pyramid in which there is one large producer

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Pyramid of Numbers

• A food chain involving parasites

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Pyramids of Biomass

• Convey energy about the amount of dry mass or
  BIOMASS at each trophic level
• They always pyramid shaped.

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Pyramids of Biomass
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Pyramids of Biomass

• Why are pyramids of Biomass always pyramid
  shaped?