How does energy move
through ecosystems?
Energy is fixed by photosynthesis
 Sunlight is converted by plants into chemical energy (C6H12O6)
 This energy is stored in the tissues of plants.
 This energy is passed between organisms within an ecosystem.
Lets start transferring the energy!
 Energy will be taken by other organisms to maintain their energy needs.
 Plants will be eaten by other organisms
 The energy conversion is through cellular respiration
 Ex. Herbivores
 Recap Energy is converted from the sun
 Into chemical energy
 Passed to other organisms within the ecosystem
 Released by cellular respiration.
Food Chains.
 Food chains are the passing of
energy from producer to
consumer until it the chain stops
and the energy is rereleased back
into the system.
Chains are just a small part of the
overall system.
 Food webs would be all the food
chains linked together.
Food Chains and food webs
Positive and negative feedback
loops can each play a role in
food webs.

If one species is removed
form or added to a specific
food web, the rest of the food
web can be affected.
 Example sea otters and kelp
forests.
We can look at food webs through
levels
Trophic pyramid
 The energy harnessed by
photosynthesis enters the system
of the primary or bottom level.
 This energy then moves up to
different levels dependent of
what eats it.
 We call these energy of food
levels
 Trophic levels.
Trophic levels
 All ecosystems are
dependent on a continuous
inflow of high energy in order
to maintain their structure
and function of transferring
mater between the
environment and organisms.
 Via: biogeochemical cycles.
 This shows that mater is
conserved, and energy is
only transferred
The average between ecosystems is 10
percent
 Energy decreases as it
moves through
ecosystems.
 Where does the energy
not transferred go to?
How do we measure this?
Primary productivity
 Is the rate at which
solar energy is
converted into
organic compounds
via photosynthesis