Environmental Science
Name: ______________________________
Food and Agriculture
Goal: The student will explain the benefits and environmental impacts of pesticide use, explain what is
involved in integrated pest management and explain how genetic engineering is used in agriculture.
Vocabulary:
1. Pesticide
2. Biological pest control
3. Genetic engineering
Chapter 9.2 continued: Crops and Soil
Pest Control
• In North America, _______% of all crops are destroyed by insects; tropical climates enough greater damage;
Kenya lost 25% of their crops from _______________________; worldwide, 33% of the world’s potential food
harvest is destroyed
• __________________ plants have more protections from pests than do crop plants; wild plants are scattered,
therefore, harder to find, have evolved defenses and have pest __________________________living in or around
them; crops plants are all in one location, a one-stop food source
Pesticides
• Over the last 50 years, many new _________________________ pesticides have been developed and farmers
have begun to rely on them to protect their crops; used to kill insects, weeds and other crop ________________
• Unfortunately, the new pesticides affect a lot _______________ than just the pests that they were designed to kill
• They can also harm _______________________, wildlife and beneficial plants and insects
Pesticide Resistance
 If large amounts of pesticides are used _____________________, over time, the pest problem will become worse.
• Pest populations ________________________ to become resistant and survive through exposure to that particular
pesticide; How? Some of the insects have a _________________________ that protects them from a pesticide;
they go on to reproduce, passing on that resistance gene to their offspring
 More than ________________ species of insects have developed resistance to pesticides since the 1940’s
Human Health Concerns
• Many _____________________________ can cause people to get sick
• Ex: California has seen an increase in ______________________ rates among children in areas which grow fruits
and vegetables with __________________ pesticide use; people applying the pesticides have to follow safety
guidelines to protect themselves from contact with these chemicals
• Workers in ___________________________ factories may become ill, as well as the people living near these
factories, from accidental chemical leaks
Pollution and Persistence
• Pesticides can become problematic for humans and wildlife because they are ________________________(don’t
break down ________________________ into harmless substances when they enter the environment), they
accumulate in the water and soil
• Ex: DDT – used in the 1940”s to kill ______________________________(malaria, lice that spread typhus);
DDT is very persistent, gradually accumulates in bodies of water, absorbed by fish, and then eaten by birds;
resulted in increased levels of DDT in bodies; __________________ were so thin they broke when sat on
(penguins, pelicans, peregrine falcons, eagles); many became endangered
• DDT _____________________________ in U.S.; but continues to remain in the environment
Biological Pest Control
• Because resistance _____________________ so rapidly, farmers and pest-control companies are using fewer
pesticides and practicing some form of pest management
•
•
Turning to ___________________________pest control (using living organisms or naturally produced chemicals
to control pests); every pests has enemies in the wild and those enemies can be used to __________________ pest
populations (ex: In India (mid-1800’s), American prickly pear cactus had been introduced into India to feed
insects that are used to make a valuable ______________dye; Cactus had no natural enemies, grew and spread.
Plants were finally controlled by the introduction of an American beetle that eats cactus
Generally, do no ____________________anything but the particular pest it is designed to control, resistance takes
longer to evolve
Pathogens
• Releasing a natural ________________________ or parasite is one method of biological control
• _________________________ (organisms causing disease) is another method
• Ex: Bacillus thuringensis (bacterium) kills larvae (caterpillars of moths and butterflies)
Plant Defenses
• Cross breeding some plant varieties to produce crops that have their own __________________________
• Tomato plants labeled “VNT” means they are resistant to certain fungi, worms and viruses
• Ex: production of chemical compounds that _____________________________pests; tougher skin
Chemicals From Plants
• Another type of biological pest control is to make use of plants’ ______________________ chemicals (Ex:
extracting chemicals from the chrysanthemum and sell it as a pesticide)
• They are ______________________________________________ (can be broken down by bacteria and other
decomposers) and are designed for use in the home because they do not harm humans or pets
Disrupting Insect Breeding
• Growth _____________________________ are chemicals that interfere with some stage of a pest’s life cycle (ex:
dogs – flea pills prevent flea eggs from developing)
• _____________________ - chemicals produced by an organism that affect the behavior of another - are also used
• Ex: female moths find mates by releasing pheromones that ______________________ males, farmers treat crops
with those pheromones to ____________________________ the males (interferes with mating)
• Another example: treat male insects with ___________________________, making them sterile; when they mate,
eggs do not get fertilized
Integrated Pest Management
 This is a ____________________________ method of controlling pests on crops (see handout)
 Not designed to ______________________________ pest populations but to reduce pest damage to a level that
causes minimal economic damage; program is designed for ______________________________ crops; can
include a _______________ of farming methods (biological pest control and chemical pest control)
 Used at specific times in the _________________________ season, fields are monitored at all times during the
growing season, when significant pest damage is found, pest is identified and program to control the
______________ is created
 Biological methods are the ________________________ methods used to control the pest (natural predators,
pathogens, parasites of the pest)
 Cultivation controls can also be used
 As a _________________ resort, insecticide may be used; changed over time so they do not have the ability to
evolve resistance
Engineering a Better Crop
 Plant breeding has been used since ________________________________ began; farmers select best tasting
tomato plants, ___________________ pest damage, save seeds and use them the next year; consequently, these
plants are more likely have _____________________for large, tasty tomatoes and resist pest
 A faster way to get the same result is to use genetic engineering (genetic material in a living cell is modified for
medical or industrial use); they will ______________________________genes from one organism and implant it
into another to get the desirable trait they are looking for (ex: pest resistant)
 Plants resulting from _________________________ engineering are called genetically modified plants (GM)
 (See handout for steps used to produce a GM plant)
Implications of Genetic Engineering
 In US, we now _________________ and use genetically engineered agricultural products every day
 Many have ___________________ been fully tested for environmental impacts; could cause problems in the
future (ex: genes are sometimes transferred from one species to another in the wild)
 GM corn plant could pass its genes to a wild corn plant; then, that corn plant could _________________ be
eliminated by a pesticide
Sustainable Agriculture
• How can we ______________________ the world’s population without depleting the world’s resources?
• Low-input farming – farming _______________________ using a lot of energy, pesticides, fertilizers and water
• Ex: ___________________ farming – farming without the use of synthetic materials, use manure, compost and
keep the land planted at all times (reducing erosion), alternating crops
• Aquaculture – “____________ farming” or raising fish in artificial environments
Lesson Reflection:
- YouTube Video: The Eyes of Nye – Genetically Modified Foods (25 min) w/Handout
Assessment:
1. Define the term pest.
2. Describe how biological pest control is part of integrated pest management.
3. Describe how genetic engineering is used in agriculture.
Active Reading: Crops and Soil
Lesson Extension (Technology/Application/Connection to Real World):
Compare the benefits and environmental impact of pesticide use.