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Roles in Ecosystems
Habitat
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A habitat is the place an organism lives.
Ecological Niche
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The ecological niche is an organism’s “job”
in an ecosystem.
It includes:
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–
–
its place in the food web
where it lives
the time of day it is active
Ecological Niche
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Each organism in an ecosystem usually has a
different niche.
This helps to reduce the amount of
competition for habitat and resources (like
food, water, etc.).
Do they have the same niche?
Do they have the same niche?
1) Red-tailed hawk
- eats mice
- hunts in fields
- hunts during the day
Do they have the same niche?
2) Eastern screech owl
- eats mice
- hunts in forests
- hunts at night
Biodiversity
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Biodiversity is the variety of life in a particular
ecosystem; also known as biological diversity
Since organisms within an ecosystem have
different niches, it allows for greater diversity
Native vs. Introduced Species
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A native species is a species that has lived in
an ecosystem for a long time.
An introduced species is a species that is
new to an ecosystem.
Introduced species can arrive naturally
(animals move, seeds carried by wind) or by
humans.
Impact of Introduced Species
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Introduced species usually cause problems in
an ecosystem.
They compete for a niche with the native
species.
Example - Starling

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Sixty European
starlings were
released in North
America in honour
of Shakespeare.
There are now 200
million of them!
Example – Cane Toad
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Cane toads were introduced into Australia to
control insects.
Example – Cane Toad
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They did not really help with
the insects.
Now they are causing a
lot of problems.
They are poisonous, so anything that eats
them dies.
They are HUGE – and will eat anything they
can swallow including many native species.
Example – Rabbits

Rabbits were brought to Australia by people.
People brought
rabbits to Australia.
Example – Rabbits
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When the rabbits multiplied, they tried many
ways to stop them:
- fences
- viruses
- fleas
Nothing
has worked!
Vocabulary
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Habitat
Ecological niche
Competition
Native species
Introduced species
Make sure
you know
these
words!