Download Ch. 6 Notes and Questions

Name: ________________________________________
Date: _____________________________
Chapter 6: Pests
Science 7 - Plants
What is a Pest?
A PEST is any organism that is causing plants to_________________ ________ than they otherwise
would. When organisms are part of a _______________ ecosystem, or are _______________ to
people, then they are not pests.
In natural systems, organisms have ________________, ______________, or competing plants
that help to keep their numbers in ____________. Pests which cause the most problems are…
1. _________________________________________________
2. _________________________________________________
3. _________________________________________________
Introduced Species:
Each food and fibre crop has its own ______________ set of pest weeds, insects and fungi. Sometimes
exotic pests are __________________from other countries by _________________
_______________ to the crop (or sometimes intended). These types of pests can often become a
______________ problem, because they may not have any __________________ predators, or
environmental _________________.
Examples:
•
•
•
Quack grass, thistles, chickweed, and dandelions
European Bark-Boring Beetle = Dutch Elm Disease
Zebra mussels
Controlling Pests:
There are various ways that pests can be _____________________…
•
__________________ enemies
•
Large pests can be __________________, or ____________ away
•
Smaller pests can be picked off the crop by______________
•
Machines (like ______________________ and ploughs) can be used to uproot pesky
weeds
•
Different crops are grown each year (_____________ __________________)
•
Regular summer fallow (controlled pests, but led to __________ _____________)
•
_________________ controls (herbicides, insecticides and fungicides)
Concerns with Chemicals:
Bioaccumulation –
•
Pollutants move from ____________ to _____________ in the food chain.
•
Bioaccumulation is a primary concern with the use of chemical pesticides, because as the
chemicals move from level to level they __________________in the organism.
•
Organisms at the _______ of the __________ ____________ are the most adversely
affected.
Soil Residue –
•
Some of the chemicals used as pesticides wash off the plants and leave _______________ in
the soil and water. If the chemical is not easily decomposed they remain in the soil and can be
_________________________.
Non-Target Organisms –
•
Pesticides are often be toxic to organisms they were ____________ _____________ ____
___________ (like earthworms who can be exposed to pesticides from soil residue and ladybug
beetles who eat aphids can be killed by the pesticide used to control the aphids)
Resistant Species –
•
As pesticide use increases, pests can (over time) _________________ ___ _______________
to the toxic effects of the chemicals being used.
•
How many Cane Toads were originally released in Australia? __________________
•
How many are there now? _____________________
•
Why? ____________________________________________________________________
Multiple Choice Questions:
1. Insects, fungi and weedy plants are the pests that cause the most damage to plants. Fungi and bacteria
cause ...(p. 164)
a)
b)
c)
d)
loss of moisture
nutrients to become inactive
infection
plant loss due to consumption
2. Canola is popular with insects, fungus and weeds. One such pest is wild oats. This pest causes damage
because it ...(p.166)
a)
b)
c)
d)
devours the canola plant
steals nutrients and moisture
causes infection in the canola seed
cuts off the flow of water to the canola stem
3. Trying to get rid of certain pests can be a problem. If a non-native species is introduced to a certain area,
without natural predators, it often becomes a pest. One such example was the introduction of the
Dandelion to North America from Europe. It was brought here as a ...(p.167)
a)
b)
c)
d)
salad vegetable
showcase flower
food source for cattle
medicinal crop
4. Herbicides, insecticides and fungicides are used to control weeds, insects and fungus. The use of these
pesticides caused another problem. They build up over time in the food chain and get stored in organisms,
just as food energy is stored. This process is called...(p.170)
a)
b)
c)
d)
eco-accumulation
bioaccumulation
pesticide residue
chemical pollution
5. Organic food is food that has been grown without the use of chemical fertilizers and chemical pesticides.
To provide the needed nutrients to grow the plants, they use ...(p.172)
a)
b)
c)
d)
manure and compost
tillage and crop rotation
mulching and companion planting
clean equipment and good seeds