Download Food Chain

How Ecosystems Work
How Ecosystems Work Big Ideas
• Energy is transferred from the sun to
producers
• Producers then transfer the energy to
consumers
• Inefficient energy transfer has an effect on
community structure
Life Depends ENERGY, LOTS
OF ENERGY…from the Sun
• Average
Star
• 93 million
miles away
• Nuclear
Fusion
• No Sun,
No Life
Life Depends on the Sun
ALL
organisms
need a
constant
supply of
energy or
they die
Why do
plants grow
upwards?
What is photosynthesis?
CO2 + H2O + Sunlight  O2 + C6H12O6
The process of
converting carbon
dioxide, water and
sunlight into oxygen
and glucose.
(In plants, algae,
some bacteria)
Occurs in chloroplasts
From Producer to Consumer
• Producer: an
organism that makes
it own food
• Plants
• Autotrophs, selffeeders
• Use sunlight
• Base of all food
chains
What role do Autotrophs
(Producers) Play?
• Gather the energy from the sun and turn it into
food via photosynthesis. Lichens are an example.
Phytoplankton get no credit
From Producer to Consumer
• Consumer: gets it
energy by eating
producers or other
consumers
• Heterotrophs
• Indirectly solar
powered
What role do
Heterotrophs
(Consumers) play?
Heterotrophs eat other
organisms to obtain
their energy.
Stored energy in food
is extracted with or
without oxygen.
Types of Consumers
• Herbivore: eats only producers (vegetarian)
• Cows, sheep, deer, grasshopper, mice, rabbits
Herbivore
Types of Consumers
• Carnivore: eats
other consumers
• Lion, hawks,
snakes, alligator,
toothed whales
Carnivore
Types of Consumers
• Omnivore: eats
both producers and
consumers
• Bears, pigs,
raccoons and most
humans
Omnivore
Types of Consumers
• Decomposer:
breaks down dead
decaying
organisms
• Critical to
ecosystem health
• Returns nutrients
• Fungus, bacteria
Detritivores and decomposers: recycle nutrients
within the ecosystem by breaking down nonliving
organic matter
Decomposer
How do Organisms Use Energy
Most organisms spend
large amounts of
time/energy in search of
food and a mate.
How do organisms get the energy
from the food (glucose)? Two ways.
Aerobic Respiration –
use oxygen to extract
energy from glucose
Anaerobic Respiration –
oxygen is NOT used to
extract energy from
glucose
Cellular Respiration (Aerobic
Respiration) allows organisms to use
the energy store in glucose.
Aerobic Respiration aka
“Cellular Respiration”
Formula
C6H12O6 + O2
CO2 + H2O + ATP
Photosynthesis & Cellular
Respiration
In photosynthetic
organisms, the processes
of photosynthesis and
cellular respiration work
together.
The products of one can
be used for the other.
Energy Transfer
Each time one
organism eats another,
energy is transferred
Ecosystems are all
about energy flowing
from one organism to
another
Energy Transfer
• Who are the
producers?
• Consumers?
• Herbivores?
• Carnivores?
• Omnivores?
• Decomposers?
• Where does the
energy start?
How does energy flow through an
ecosystem?
• A food chain is a series of
steps in which organisms
transfer energy by eating
or being eaten (arrows?)
• All food chains have a
producer on bottom, which
supplies each level above
with food
• Energy flows in one
direction through a Food
Chain.
• Each step in a food chain is
called a trophic level.
Energy Transfer
• Food Chain: sequence
in which energy is
transferred from one
organism to another
• Starts with producers
• Energy flows in one
direction
Food Web
A food web shows the
various food chains
within an ecosystem.
Can you describe one
food chain within this
food web?
What is missing from
this food web?
Energy Flow
• Food Web:
shows many
feeding
relationships
that are
possible in a
ecosystem
• More
complex and
realistic
Energy Flow
• Trophic Level:
each step which
energy is
transferred
How is energy monitored in a
food chain?
Energy Pyramid track available energy in a
food chain. Only 10% of the available energy
is passed from one trophic level to the next.
Energy Pyramid
1 unit of energy
10 units of energy
100 units of energy
1,000 units of energy
10,000 units of energy
Energy Flow
• At each trophic
level about 90% of
energy is lost
• Cellular respiration
• Lost to heat body
and carry out living
Energy Flow
• Why are there fewer
organisms at the top?
(Why fewer bears
than the fruit they
feed on)
• Why aren’t there
more than 4-5 trophic
levels in a energy
pyramid?
Review
• Energy is transferred from the sun to producers
through the process of photosynthesis
• Consumers use the glucose made by producers
for energy
• Food webs show more complex & realistic feeding
relationships in a ecosystem
• Energy pyramids track available energy in a food
chain. Only 10% of the available energy is passed
from one trophic level to the next.