Relationships in an Ecosystem
Instructions:

View this powerpoint on concepts and
terms that will be useful to you in
understanding relationships within an
ecosystem.

As you view each slide, follow the
instructions on the viewing guide handout.
Definitions

Ecology: The study of the interactions among
organisms and between organisms and their
environment

Biotic: The living parts of an environment

Abiotic: The non-living parts of an environment
Overview: There are 5 Levels of
Ecological Study.

Individual Organisms

Populations

Communities

Ecosystems

Biosphere
Populations
 A group
of
individual
organisms of the
same species
Communities
 The
populations
of all the species
that inhabit a
particular area
Ecosystems
Includes the abiotic factors and
biotic factors in an area
Biosphere

The sum of all the Earth’s ecosystems
Within an ecosystem,
there are various feeding
relationships…
Food Chain
 A pathway
of food transfer in an
ecosystem from one trophic
(feeding) level to another is called a
food chain.
 There are many different food
chains in every ecosystem.
This diagram shows
two food chains,
one on land and one
in the sea.
Notice the direction
of the arrows in the
diagram. Since
food provides
energy for living
things, the arrows
show the direction
of energy flow
through the chain.
Producers

Producers use the sun’s
energy to create
chemical energy for
themselves. (Through
the food chain, this
energy is transferred to
consumers.)
Consumers

Primary Consumers: Organisms that eat
producers (herbivores or omnivores)

Secondary Consumers: Eat primary
consumers (carnivores or omnivores)

Tertiary Consumers: Eat secondary
consumers (carnivores or omnivores)
Decomposers

Decomposers are consumers that obtain energy by
feeding on and breaking down wastes and remains
of dead organisms.

Major decomposers are bacteria, fungi and worms.

Decomposers are responsible for recycling
chemicals in the ecosystem.
Food Webs
In every ecosystem, there are many food
chains that are interconnected to make food
webs.

The next slide shows the interconnected
pattern of feeding in a food web.
Notice: some organisms have several sources
of food they can eat and some organisms are
eaten by several different kinds of consumers.
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