Download Invasive species - Mrs. Anderson`s Sciences

Notes #3
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Native species are plants and animals that
naturally inhabit an area.
Introduced species are species which are
introduced into an ecosystem and usually
either benefit or harmless to the ecosystem
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Also called foreign species
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Invasive species are organisms that can take over
the habitat of native species or invade their bodies.
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Because of climate change and increased world
travel and trade there is more movement of
species into new ecosystems.
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The number of invasive species in ecosystems is
increasing
This can lead to loss of biodiversity
Characterized by
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High reproductive rates
Being aggressive competitors
Lacking natural predators in new habitat
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Invasive species can exploite niches and affect
native species through
Competition
 Predation
 Disease
 Parasitism
 Habitat alteration
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Invasive species compete against native species
for:
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Food
Habitat
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Unbalance natural resource sharing
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Example: burweed on Saltspring Island
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From South America
Competes with 4 natural species
Spiny tips
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Invasive species may act as a predator to native
species in the ecosystem
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Prey have not adapted to that predator
(escape/fight)
Example: Yellow crazy ants
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From West Africa
Introduced to Christmas Island Austraila
Build supercolonies (500 football fields)
Prey on many things including red crabs (keystone
species)
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Invasive species like viruses and bacteria and
other organisms
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Weaken immune systems in native species
Other species can outcompete weak species
Example: Parasitic Sea Lamprey
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From Atlantic Ocean
Moved into Great Lakes
Attach to fish and suck out body fluids
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Invasive species can change ecosystems
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Native species unable to survive
Examples
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Light levels
Oxygen levels in water
Soil chemistry
Increased erosion
Unbalance nutrient cycles and energy flow
Example: Wild boars
Damage systems by rooting, wallowing, and spreading
weeds
 Omnivores: eat birds, reptiles, frogs, soil organisms, fruit,
seeds, bulbs
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Eurasian milfoil
Norway rat
American bullfrog
European starling
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Group Activity
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8 groups
Each group looks at one invasive species example
 Find out:
 Where it is invading
 How it got there
 What it does in the system
 How is it being combated
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2 groups get together compare notes, then share with
class