Transcript SNC1PL Pests and Pesticides

Natural ecosystems have
high biodiversity
Artificial ecosystems
have low biodiversity
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Agro ecosystems (farms) are artificial
ecosystems created to maximize the
production of one species.
To maximize this crop, organisms that
compete with, or damage crops (pests) must
be regulated
Colorado Potato Beetle
(Leptinotarsa decemlineata)
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Pesticides are substances that may be
used to kill pests biologically and/or
physically.
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Herbicides kill plants
Rodenticides kill rodents
Fungicides kill fungus
Insectides kill insects
Pesticides may be broad-spectrum
(affecting many different species) or
narrow-spectrum (affecting a limited
number of species)
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Odourless, broad spectrum
pesticide derived from the Jicama,
Yam, or Mexican Turnip
Linked to the development of
Parkinson’s Disease (interferes
with cellular respiration)
Originally added to fishing waters
to easily kill fish, which would then
float to the surface
APPROVED FOR USE BY SOME
ORGANIC FARMS
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Synthetic (made by humans),
broad-spectrum pesticide
used to kill weeds.
Very low persistence (breaks
down easily)
Works by removing a weed’s
ability to grow
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Derived from bacteria (Bacillus thuringinesis)
since 1920.
Narrow-spectrum pesticide that is highly
toxic to moth and butterfly caterpillars
1) Non-target species:
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broad spectrum pesticides tend to kill off non
target species and predators of pests.
Therefore more pesticides must be used to
artificially protect crops.
2) Bioamplification:
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Some pesticides are not soluble in water and
tend to be stored in the fat cells of its victims
(bioaccumulation).
As higher organisms feed on lower trophic
levels, the concentration of pesticides builds
up causing lethal doses of pesticides to
organisms high on the food chain.
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Put your bags and notebooks on your desk
or on the side benches
Tuck your chair in
Find a spot to stand somewhere in the
classroom
Only move when Mr. Chawla gives further
instructions
Hawk
Lamprey
Perch
Algae
Hawk
Lamprey
Perch
Algae
3) Pesticide Resistance:
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Some pests are able to mutate and develop
resistance to pesticides over time. This
means new pesticides must be created since
the old versions may not work anymore
(EXPENSIVE!)