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Ecological Relationships
Biosphere
 The biosphere is the portion of the earth in
which living things and non-living things
exist.
 The ecosystem is a community and the
physical environment that it occupies.
Biotic vs. Abiotic
 Biotic factors are living
factors
 Examples include:
animals and plants
Abiotic Factors
 Abiotic factors are nonliving factors in the
environment.
 Examples: Water,
Oxygen, Light, Sun
Temperature, Soil, Rocks
 Biotic factors depend on
abiotic factors for there
survival.
Abiotic factors sometimes
become limiting factors.
A limiting factor is a factor
that controls a process, such
as an organism growth or
species population, size,
or distribution
Producers, Consumers and
Decomposers
 Energy must flow through an
ecosystem to allow organisms to
survive and reproduce.
 Producers are organisms that are
autotrophs. They make up the base
of the energy pyramid.
Examples of autotrophs
include organisms that
perform what process?
 Producers are the most abundant in
the ecosystem.
– Producers are autotrophs which
are organisms that can produce
their own food using abiotic
factors. (Plants and grass)
Consumers
 Consumers are heterotrophs
and must obtain nutrients from
other organisms.
– There are primary consumers,
also known as, first level
consumers.
– They make up the first level of
the energy pyramid.
– An example of primary
consumers are herbivores.
(organisms that eat producers)
Secondary Consumers
 Second level on the energy
pyramid.
 Organisms that make up the
second level are considered to
be carnivores or meat eaters.
 Examples include: frogs,
snakes,
Tertiary Consumer
 These organisms make up the third
level of the energy pyramid.
 These organisms are considered to
be omnivores, which are
organisms that eat meat and
plants.
 Examples include: grizzly bear,
raccoons, skunks, owls
Decomposers
 These are the “recyclers” of our food webs
and chains. They generate important
nutrients for the soil so that producers can
grow.
 They work by breaking down dead
organisms so that the decay can be reused
by the ecosystem.
 Example of decomposers include:
mushrooms, bacteria, mold and
worms.
 Without decomposers there would be no
transfer of energy. Every food chain and
web needs decomposers.
The Energy Pyramid
 The base of the
pyramid is larger and
as you move up each
trophic level it
becomes more
narrow.
 Why is it bigger on the
bottom?
 Why does it become
more narrow?
 As you move up each
trophic level the
amount of energy
transferred between
organisms and the
biomass (amount of
organisms)
decreases.
Food Chains and Webs
 Organisms carry out feeding relationships
with each other.
 When a series of organisms pass energy to
and from each other it is called a food
chain.
 Series of food chains interconnected
create food webs.
The arrows in the chain represent the transfer of energy.
The direction of the arrow represents where the organism
is getting the energy from.
Where is the grasshopper getting it’s energy from?
Where is the mouse getting it’s energy from?
Carrying Capacity
 Carrying capacity is the
amount of organisms
that environment can
hold.
 If carrying capacity is
reached no more
organisms will
reproduce.
Symbiotic Relationships
 There are four types of close (symbiotic)
relationships that organisms can have.
 They include: Predator-Prey,
Commensalism, Mutualism and
Parasitism.
Predator/Prey
 Relationship of the hunter
(predator) and the hunted (prey)
 Examples include:
Predator
Hawk
Snake
Prey
Trout
Mouse
 Commenselism- A relationship in which one
organism benefits and the other is not
affected (+,o).
– Examples include: Shark and Remora fish
Barnacles and Whales
 Mutualism- A relationship where both
organisms benefit. (+,+)
– Examples include: Flower and bee
Bacteria and legumes
 Parasitism- when one organism benefits
and the other is harmed (+, - ).
– The organism that is being harmed is called the
host organism.
Examples include:
Host
Dog
Feet
Parasite
Flea
Fungus
Materials Cycle
 There are certain materials that get
recycled in the environment.
 The three materials cycle include the
carbon-oxygen cycle, the water
cycle and the nitrogen cycle.
Carbon-Oxygen
 This cycle involves the
process of
photosynthesis and
respiration.
 It is the recycling of
carbon dioxide,
water, oxygen and
glucose
The Water Cycle
 It is the material cycle
the recycles water.
 It involves the process of
photosynthesis,
transpiration ,
evaporation,
condensation and
respiration.
The Nitrogen Cycle
 Nitrogen cycle recycles
the nitrogen necessary
for production of
proteins.
 It involves decomposers
and other bacteria that
break down nitrogen
wastes and the remains
of dead organisms.
Ecological Succession
 Ecosystems go through changes until a
climax (stable) community is attained.
 The replacement of one community by
another is called ecological succession.
 A community can be replaced by another
over a long period time.
Primary vs. Secondary Succession
 Primary succession begins with pioneer
organisms ( bare rock and lichens) and
works it way up to a forest or a “climax
community”
 Secondary succession is when you have a
climax community and a natural disaster
like a fire destroys and it must rebuild itself
again.