Energy Flow
Section 3-2
Objectives:
•Trace the flow of energy as it decreases
through the trophic levels from producers
to the quaternary level.
•Contrasting autotrophs and heterotrophs
•Describing the niche of decomposers
Producers:
• Definition????
• What is the main source of energy
for life on Earth?
• What about organisms at the
bottom of the ocean, where
sunlight doesn’t reach?
• These organisms rely on energy
stored in inorganic chemical
compounds (i.e., salts).
Producers, continued…
• Producers are also called
autotrophs.
– “auto” = ?
– “troph” = ?
• Some producers capture the energy
from sunlight through a process
called _________________.
• Photosynthesis uses light to convert
____________ and _____________ to
____________ and ______________.
Producers, continued…
• Photosynthesis
– “photo” = ?
– “synthesis” = ?
• Chemosynthesis
– “chemo” = ?
– “synthesis” = ?
Photosynthesis vs.
Chemosynthesis
• Photosynthesis:
– 6CO2 + 6H2O → C6H12O6 + 6O2
– Carbon dioxide + water yields
carbohydrates (glucose) and oxygen, in
the presence of sunlight.
• Chemosynthesis:
– Hydrogen sulfide and oxygen combine
to form sulfur compounds, which are
then used with carbon dioxide to make
carbohydrates.
– What do sulfur compounds smell like?
Consumers:
• What are they??
• AKA, heterotrophs:
– “hetero” = ?
– “troph” =
• Types of heterotrophs (consumers):
–
–
–
–
–
Herbivores
Carnivores
Omnivores
Detritivores
Decomposers
Feeding Relationships
• Where does the energy flow begin
in an ecosystem?
• ANSWER: sunlight or inorganic
chemical compounds
• Then it flows in one direction, from
producers to various levels of
consumers (heterotrophs).
Food Chains:
• Def: a series of steps by which
organisms transfer energy by
eating or being eaten.
http://ejad.best.vwh.net/java/population/facts_foodchain.html
Food Webs:
• Def: a network of complex interactions of
all the food chains in an ecosystem.
Trophic Levels
1. Producers
2. Primary consumers (herbivores)
3. Secondary consumers
(carnivores which eat herbivores)
4. Tertiary consumers (carnivores
which eat other carnivores)
5. Apex predators – carnivores
which have no predators
Ecological Pyramids