Transcript Community Interactions

Section 3.3

Describe (at least) 3 things that make up an
organism’s niche:
 Habitat
 What/when it eats
 What eats it
 How it reproduces
 How much water it needs
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Explain how an organism’s niche is slightly
different than its habitat:
 The niche is more than just where the organism
lives, it also includes what it does.
 Organisms may share the same habitat, but never
the same niches.
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Examine fig. 1 on page 68, then explain how
the lynx and the wolf are able to share the
same habitat without too much competition.

Examine fig. 1 on page 68, then explain how
the lynx and the wolf are able to share the
same habitat without too much competition.
 Each has different behaviours or traits that allow
them to exploit different parts of the niche:
different timing, different hunting strategies.
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Explain what happens when two species are
forced to occupy the same niche rather than
the same habitat.
COMPETITION will occur!

Define competition:
 Competition occurs when species make use of
the same resource so that their niches conflict or
overlap with each other.

Explain the difference between interspecific
competition and intraspecific competition.
 Interspecific competition:
▪ Competition between different species.

Explain the difference between interspecific
competition and intraspecific competition.
 Intraspecific competition:
▪ Competition
between
members of
the same
species.
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Explain how the hawk and the owl have
adapted traits that have allowed them to
adapt to competition between them.

Explain how the hawk and the owl have
adapted traits that have allowed them to
adapt to competition between them.
 The hawk works on the day-shift (diurnal).
 The owl works on the night-shift (nocturnal).
 This way, even though their niches are similar,
they don’t overlap so that they can coexist 

Define adaptive radiation:
 Adaptive radiation occurs when species adapt
differently to changes in the environment.
 Species become
specialized in
order to exploit
smaller or
different parts of
a habitat.

How did the finches on the Galapagos Islands
undergo adaptive radiation in order to reduce
competition among themselves?
 Over time, the finches adapted different beak
sizes and shapes in order to exploit the different
food sources available to them.

Adaptive Radiation

Define proliferation:
 Proliferation occurs when organisms with these
adapted traits increase in numbers due to natural
selection.

Define a foreign species:
 Species that are introduced into an area that they
are normally not native to.

So why do these foreign species often pose a
real danger to native species?
 1. Sometimes they out-compete native species for
a niche.
 2. They rarely have any natural predators in the
new habitat.

Give one example where the introduction of a
foreign species is beneficial.

Give one example where the introduction of a
foreign species is beneficial.
 The introduction of food crops like corn, wheat,
and fruit trees.

Give one example of a foreign plant species
that was introduced into BC that proved to be
harmful to the ecosystem.

Give one example of a foreign plant species
that was introduced into BC that proved to be
harmful to the ecosystem.
 Eurasian milfoil or Scotchbroom.

Give two examples of foreign animal species
that were either intentionally or
unintentionally introduced to BC.

Give two examples of foreign animal species
that were either intentionally or
unintentionally introduced to BC.
 European starling and Pacific Oyster
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
The word succession means “to take place
of”.
Define ecological succession:
 The gradual change in the type of plants in a
community.


Suppose a logging company has clear-cut a
section of the forest for its timber, but never
replanted the trees that it cut down.
Over time, if the
area was ignored,
ecological
succession would
occur.

What is the name of the first step in
ecological succession?
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What is the name of the first step in
ecological succession?
 Pioneer species.

Give an example of an organism that very
often begins primary succession and what
they are called.
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Lichen or mosses often appear first because
they can grow during conditions of no soil or
nutrients and begin by breaking down rock
and trapping windblown particles and
producing soil.
They are called pioneer
plants.
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In the end, if there is sufficient rainfall,
nutrients and sunlight, the community will
develop into a stable ecosystem called a
climax community.

Define secondary succession:
 Secondary succession occurs when there is
already decent soil in the area, but something like
a fire or clear-cut logging has removed the natural
vegetation.
 Seeds that are in the soil, or brought by the
wind/birds now become the pioneer species
eventually becoming a climax community.
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CYU 3.3 page 73:
1, 3, 4, 5, 6, (full sentences)
7, 8, ( multiple choice)
9, 11, (full sentences)