LO: How do organisms
interact in an ecosystem?
DN: What is a niche? Can
two organisms occupy the
same exact niche? Explain.
HW: textbook page 85#19-22
Why do organisms need to
eat?
To get ENERGY!!
Cell Respiration:
C6H12O6 + O2
ATP + CO2 + H2O
Organism Categories:
Organisms
Producers
(Autotrophs)
Consumers
(Heterotrophs)
Decomposers
Organism Categories:
Consumers
1’ Consumers
2’ Consumers
3’ Consumers
Herbivore
Carnivore/
Omnivore
Carnivore/
Omnivore
Herbivores – eat only producers
Carnivores – eat only meat
Omnivores – eat both producers & meat
Ecosystem Relationships:
Symbiotic Relationships
1. Mutualism
2. Commensalism
3. Parasitism
4. Predator & prey
Parasitism:
Fluke Worms
Tick
•Parasites are organisms that attack
other live organisms called hosts.
•parasite benefits and host is affected
(+, -)
Mutualism:
both benefit (+, +)
The Nile crocodile
opening its mouth to
permit the Egyptian
plover to feed on any
leeches attached to its
gums.
Bee eats nectar &
at the same time
picks up pollen to
be spread to other
flowers.
Commensalism:
one benefits
and other is
unaffected
(+, 0)
Barnacles are non-motile, & they adhere to
the fins of whales. This allows them to be
taken to places where there is food. The
whale is not affected.
Predator & prey – predator
benefits and prey is affected
How do the cows we eat get
their energy?
Primary consumers get their
energy from the producers they eat
How do producers get their
energy?
The primary
source of energy
for living things
is the sun.
Autotrophs
capture this
energy through
the process of
photosynthesis
How is energy transferred in
a community?
Energy is transferred by
consuming other
organisms
In which direction is the energy
moving? Why?
Food Chains
Scientists depict
this transfer of
energy as a
Food chain.
They show the
transfer of
energy from one
organism to
another in a
community
Food Webs
Show many food chains
interconnected together
Energy Pyramid
2’ Consumers
1’ Consumers
Producers
Energy Flow
3’ Consumers
Sun’s Energy in an Ecosystem
Some of the
energy is
used by each
organism and
some of it is
transferred as
heat energy
to the
environment
Why is there so little energy at
the top of the pyramid?
• Most of the energy from the sun has been
used or lost by organism in the lower levels
• Only about 10% of the energy available at
each level is transferred to the NEXT level.
1%
10%
100%
Ecological pyramids
Energy Pyramid
Shows the relative amount of
energy available at each trophic
level. Organisms use about 10
percent of this
energy for
life processes.
The rest is lost
as heat.
Biomass Pyramid
Go to
Section:
Represents the amount of
living organic matter at each
trophic level. Typically, the
greatest biomass is at the
base of the pyramid.
Pyramid of Numbers
Shows the relative
number of individual
organisms at each
trophic level.