Transcript Trophic level

Cells Need Energy To:
• Digest food
• Grow
• Build macromolecules
The original energy source for
most organisms is LIGHT.
Photosynthesis
• process that converts solar energy into
chemical energy stored in the bonds of organic
compounds, usually carbohydrates
6CO2 + 6H2O + light energy  C6H12O6 + 6O2
Respiration
• The release of chemical energy from food for
cellular use
• C6H12O6 + 6O2  6CO2 + 6H2O + energy
• AUTOTROPHS
– Organisms that use energy to
make their own food
(producers)
• HETEROTROPHS
– Organisms that cannot make
their own food (consumers)
– Feed on autotrophs or on other
heterotrophs that feed on
autotrophs
• All life depends on
AUTOTROPHS.
Name
Who Eats What in an Ecosystem
Energy Source
Examples
Producer
Makes its own food
Consumer
Gets energy by eating
other organisms
Herbivore
Eats only producers
cows, sheep, deer,
grasshoppers
Carnivore
Eats only other
consumers
lions, hawks,
wolves, pike
Omnivore
Eats both producers and
consumers
bears, pigs,
humans
Decomposer
Breaks down dead
organisms, returning
nutrients to the soil or
water
fungi, bacteria
grasses, ferns,
trees, some
bacteria
• Trophic level: each step in the transfer of
energy through an ecosystem
• The total energy of one trophic level never
flows to the next level
• Lower levels contain more total energy
• Specific sequence in
which organisms obtain
energy in an ecosystem
•Usually only 4 or 5
levels
•Only a portion of the
energy available to
organisms at each level of
the food chain is stored
•Only the stored energy is
available to organisms at
the next trophic level
• The interrelated food chains in
an ecosystem
Numbers Pyramid
• compares the number of individuals
at each trophic level
Biomass Pyramid

compares the amount of biomass
(total dry weight of the organisms in an
ecosystem)
Energy Pyramid

compares the total amount of
energy in each trophic level