Energy Flow
Energy Flow
Energy Flow
First law of
Thermodynamics:
Energy cannot be
created or destroyed
(but it can be
transformed into
stored energy & heat)
ENERGY LEAVES ECOSYSTEM
Second law of
thermodynamics:
Energy is lost as
energy is transformed
In ecosystem, when
energy is
transformed, some
energy is lost as
HEAT
ENERGY PATHS
3 ways to 1. Food Chain: Single path
illustrate
energy flow
CONSUMER CONSUMER
DECOMPOSER
(OMNIVORE) (HERBIVORE)
PRODUCER
FOOD CHAINS AND WEBS
Practice! Draw a food
CONSUMER
chain that includes the (CARNIVORE)
following organisms:
grasshopper
mouse CONSUMER
(CARNIVORE)
grass
owl
CONSUMER
Now label the organisms (HERBIVORE)
as producers, consumers
(which type?), or
decomposers PRODUCER
FOOD CHAINS/WEBS & ENERGY PYRAMIDS
Food chains/webs can be
written as a pyramid:
represents the
ENERGY STORED
energy for those BY PRODUCERS
organisms
TROPHIC LEVELS
Energy is lost with each trophic
~90% is released to the environment as heat
~10% of the energy is used
Only about
10% of the
energy from
one level is
passed on to
the next level
QUICK REVIEW
Practice!
If 100% of the energy is available at the first trophic
level, what percentages of the energy are available at
the second and third trophic levels?
1%
10%
100%
QUICK REVIEW!
All organisms in an ecosystem need _______
energy
from food to live. An energy ________
pyramid shows
how much food energy is passed from one
________
organism to another through food chains.
__________
Producers have the largest spot at the base
of the pyramid. Altogether, only about _____
10% of
the food energy at each level gets passed up to
the next level.