Transcript Ecological Niche - NCEA Level 3 Biology

Ecology
Some Definitions
• An ecosystem – all the living things in an
area plus the physical or abiotic factors.
• A habitat – the place or environment in which
specific organisms live.
• A species - a group of similar organisms that
normally interbreed in nature to produce
fertile offspring.
Ecological Niche
Ecological Niche
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REMEMBER
The habitat is an organism’s address.
The ecological niche is its profession.
A limiting factor is any variable
environmental factor that limits the activity of
an organism or population.
Explain More
• the niche is the “role” the species plays in the
community of interacting species.
• This includes:
– Where it lives
– What it eats
– How it responds to stress
– What limits its population growth.
It is the whole of the organism’s use of the
biotic and abiotic resources in its
environment.
Ecological Niche
• Simply put the niche is a description of the
opportunities provided by the habitat and the
adaptations of the organism to make the
most of those opportunities.
Gause’s Principle
No two species with identical ecological niches
can coexist for long in the same place.
Fundamental Niche
• This refers to the resources a population
could theoretically use in an ideal situation.
Realised Niche
• This refers to the resources a population can
actually use (remember it is affected by all
the interactions with other organisms).
Example
• 2 species of barnacle grow on the rocky
shore. Balanus balanoides and Chthamalus
stellatus
• C. stellatus, which are smaller, live at the top
of the rocks, while the B. balanoides, the
larger, live lower down.
• The bigger barnacles can’t stand the period
of dryness when the tide goes out, the small
barnacles can.
Example
• If you remove all the B. balanoides from
lower down, the smaller ones, C. stellatus,
move quickly in and are very happy there. It’s
just that they normally can’t stand the
competition from the bigger barnacles.
• The fundamental niche for the small
barnacle is the whole of the rock, but its
realised niche is the upper layers of the rock.
Barnacles