Transcript Energy Flow Through Ecosystems

Unit 6 - Ecology
1
Energy Flow through
Ecosystems
Energy Flow
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 Energy in an ecosystem originally comes from
the Sun.
 Autotroph - any organism that can produce its
own food supply.
o also called Producers
o Ex: plants, algae, some protists, and some
bacteria
• Energy flows through ecosystems from
producers to consumers
Producers
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• Sunlight is the main source of energy for most
life on earth.
• Producers contain chlorophyll & can use
energy directly from the sun
Niche of a Producer
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 Producers capture energy and transform it into
organic, stored energy for the use of living
organisms.
 This organic energy is in the form of glucose.
o photoautotrophs using light energy (ex.
plants)
o chemoautotrophs using chemical energy (ex.
cyanobacteria)
Photoautotroph
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 Producer that captures energy from the sun
through process of photosynthesis:
o adds oxygen to the atmosphere
o removes carbon dioxide from the atmosphere
Algae
Chemoautotrophs
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 Captures energy from the bonds of inorganic
molecules such as hydrogen sulfide. Process is
called chemosynthesis
 CO2 (Carbon Dioxide)+ O2+ 4H2S(Hydrogen Sulfide)  CH2O (Food) + 4S + 3H2O
 Often occurs in deep sea vents
Consumers
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 Heterotrophs - eat other organisms
to obtain energy.
o Herbivores - eat only plants
o Carnivores - eat only other animals
Consumers cont…
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 Heterotrophs eat other organisms to obtain
energy.
o
Omnivores - eat plants and animals
o
Decomposers - feed by breaking down dead organic
material, then absorbing the released nutrients.
 Detritivores - earthworms, feed on detritus.
 Saprotrophs - fungi and bacteria
Feeding Relationships
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• Energy flows through an ecosystem in one
direction from producers to various levels of
consumers.
Feeding Relationships
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
Food Chain
 A sequence in which energy is transferred
from one organism to the next as each
organism eats another organism.
Feeding Relationships
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Identify Producer, Consumer & Decomposer
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Identify Producer, Consumer & Decomposer
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Food Web
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
Food Web
 A food web shows many feeding relationships
that are possible in an ecosystem.
 more
realistic path through an ecosystem
made of many interconnected food chains
Food Web
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Trophic Levels
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 Each step in the transfer of energy through a food
chain or food web is known as a trophic level.
 Producers
 ALWAYS the 1st trophic level; how energy enters
the system
 Herbivores
 2nd trophic level
 Carnivores and Omnivores
 Make up the remaining trophic levels
 Each level depends on the one below it for energy.
Trophic Levels
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2nd trophic level
Primary Consumer
3rd trophic level
Secondary Consumer
Producer 1st tropic level (trapped
sunlight & stored food)
4th trophic level
Tertiary consumer
5th trophic level
Quaternary
Consumer
Ecological Pyramids
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 Graphic representations of the relative
amounts of energy or matter at each trophic
level:
 Energy Pyramid
 Biomass Pyramid
 Pyramid of Numbers
Energy Pyramid
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Energy Pyramid cont…
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•Amount of available energy decreases for higher
consumers
•It takes a large number of producers to support a
small number of primary consumers
•It takes a large number of primary consumers to
support a small number of secondary consumers
Energy Pyramid cont…
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Biomass Pyramid
Pyramid of Numbers