Transcript 02-Ecological Niche student handout

The Ecological Niche and
Exotic Species
Ecological Niche
An Ecological Niche is:
the job or role an organism occupies in its
ecosystem. This role includes where it lives and
everything it does to survive and reproduce
• A species' niche includes:
– Nutrition - its method of obtaining food
– Habitat - where it lives in the ecosystem
– Activity – when it is active
• Species occupying the same
niche will compete for limited
resources!!
• Examples:
Food, shelter, light, water
Examples
• Raccoon
– Omnivore
– Forest/Urban areas
– Nocturnal
• American Toad
– Adult: carnivore; Tadpole: herbivore
– Wet areas (ponds, ditches, creeks)
– Nocturnal
Examples
• Red-Tailed Hawk
– Carnivore
– Open fields,
forest edge
– Diurnal
– Non-migratory
Terms
• Nocturnal: Active at night
• Diurnal: Active during the day
• Competition: Organisms striving to
acquire resources in order to
survive at the expense of others.
Terms
• Intra-specific competition:
Competition within the species.
• Inter-specific competition:
Competition between species.
Competition Between 2 Species
for a Niche
• Two species partially share a niche: both compete in
the overlapping parts of the niche for resources,
nesting sites, or territory. If the overlap is minimal,
both species can coexist.
• Ex. Owl
Hawk
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•
•
•
*soars over grasslands
* active during daylight
* eyes detect colour
* nests in tops of trees
* hunts prey in the forest (short wing)
* active at dusk and night
* eyes detect motion
* nests in cover of forest
These organisms feed on many of the same
organisms but occupy distinctly different
niches due to species adaptations. These
adaptations allow the organisms to coexist
Competitive Exclusion Principle
• The competitive exclusion principle states that:
only 1 species can occupy a whole niche in an
ecosystem at a time.
One species will always be superior to the other in
utilizing the niche. The 2nd species will disappear from
the ecosystem.
• Examples
• Rabbit vs. wombat
• Goby vs. mottled sculpin
Exotic Species
• Exotic species are those that are not indigenous to
an area
• The introduction of an exotic specie often results in
competition between the exotic and the indigenous
species.
• If the exotic has a competitive advantage it will often
displace the native specie.
Examples
• Zebra mussels
– Lake Erie
– Arrived on bottoms of
boats from Caspian Sea
– Pearly mussel displaced
• Cane Toad
– Australia
– Introduced (from Hawaii)
to control cane beetle
population
– Displaced native toads
Examples
• Killer Bees
– Brazil
– Introduced (from Africa) to
cross-pollinate with native
honey bees
– Will attack in large
numbers
Scientific
consequences
Social
consequences
Legal & ethical
consequences
Invasive species
has appeared
Economic
Environmental
consequences
consequences
Personal
consequences
Consequence Mapping
Article Analysis
• Read article.
• Answer questions.
Read pg 7 – 13, 49 – 64
Questions pg 55 1, 4, 5
pg 64 2, 4, 5