Lecture Outlines
Chapter 10
The Science behind the
4th Edition
© 2011 Pearson Education, Inc.
This lecture will help you understand:
• Challenges of feeding a
growing human population
• The Green Revolution
• Preserving crop diversity
• Strategies of pest management
• Pollination
• Genetically modified food
• Feedlot agriculture
• Aquaculture
• Sustainable agriculture
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Transgenic maize in Southern Mexico
• Corn (maize) originated in
Mexico 9,000 years ago
• In 2001, genes from
genetically modified corn
appeared in traditional maize
• These transgenes (genes from
another species) came from
U.S. corn
• Could contaminate native
• The agrobiotech industry
questioned these findings
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Today, we are producing more food per
By 2050, we will have to
feed 9 billion people
• Food production exceeds population growth
• We produce food through technology
- Fossil fuels, irrigation, fertilizer, pesticides,
cultivating more land, genetic engineering
• Today, soils are in decline and most arable land is
already farmed
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Undernutrition and food security
• 1 billion people do not have enough to eat
• Undernutrition = people receive fewer calories than
their minimum requirements
- Due to economics, politics, conflict, and
inefficiencies in distribution
• Most undernourished live in developing nations
- But 36 million Americans are “food insecure”
• Food security = guarantee of an adequate, safe,
nutritious, and reliable food supply
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Food security
• Undernutrition decreased between 1970 and 1990
• Higher food prices (2006–2008) and the economic
slump (2008–2009) increased the number and
percent of hungry
15% of the world’s population is hungry
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Overnutrition and malnutrition
• Overnutrition = receiving too many calories each day
- Developed countries have abundant, cheap junk
food, and people lead sedentary lives
- In the U.S., 25% of adults are obese
- Worldwide, over 400 million people are obese
• Malnutrition = a shortage of nutrients the body needs
- The diet lacks adequate vitamins and minerals
- Can lead to diseases
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Malnutrition can lead to diseases
• Kwashiorkor = diet lacks
protein or essential amino acids
- Occurs when children stop
- Bloated stomach, mental and
physical disabilities
• Marasmus = protein deficiency
and insufficient calories
- Wasting or shriveling of the
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The Green Revolution increased yields
• Spread to the developing
world in the 1940s
- Wheat, rice, corn
• Depended on lots of:
- Synthetic fertilizers
- Chemical pesticides
- Irrigation
- Machinery
Norman Borlaug won
the Nobel Peace Prize for
his work
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Consequences of the Green Revolution
• From 1900 to 2000, cultivated area increased 33%
- While energy inputs increased 80 times
• Positive effects on the environment
- Prevented some deforestation and land conversion
- Preserved biodiversity and ecosystems
• Negative effects on natural resources
- Pollution, erosion
- Salinization, desertification
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The Green Revolution
• Intensified agriculture saved millions from starvation
- Turning India into a grain exporter
• Rich farmers with lots of land benefited
- Poor farmers were driven off
the land into cities
Today, yields are
declining in some
Green Revolution areas
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Monocultures increase output, but at a
• Monoculture = large expanses of a single crop
- More efficient, increases output
- Devastates biodiversity
- Susceptible to disease and pests
• Human diet is narrowed: 90% of our food comes from
15 crop and 8 livestock species
Armyworms easily
destroy monocultures
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Biofuels affect food supplies
• Biofuels = are derived from organic materials
- Replace petroleum in engines
• Ethanol = a biofuel derived from corn
- 2007 subsidies doubled production
• Food prices increased
- Farmers sold corn for ethanol, not food
- Farmers planted biofuels, not food crops
- Riots erupted in many nations
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Preserving crop diversity: insurance against
• Preserving native variants protects against crop failure
• Monocultures are vulnerable
- Wild relatives contain genes that can provide
resistance to disease and pests
- But Mexico has lifted its ban on transgenic corn
• We have lost a great deal of genetic diversity in crops
- U.S. crops have decreased 90% in diversity
• Market forces discourage diversity in food’s appearance
- Food producers prefer uniform, standardized food
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Seed banks are living museums
• Seed banks = institutions that preserve seed types as
living museums of genetic diversity
- Seeds are collected, stored, and periodically planted
The “doomsday seed vault” in Norway stores
millions of seeds from around the world
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We have thousands of pesticides
• Pest = any organism that damages valuable crops
• Weed = any plant that competes with crops
• Pesticides = poisons that target pest organisms
- Insecticides = kill insects
- Herbicides = kill plants
- Fungicides = kill fungi
• 400 million kg (900 million lb) of pesticides are
applied in the U.S. each year
- 75% of this is applied to agricultural land
• $32 billion/year is spent on pesticides worldwide
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Pests evolve resistance to pesticides
• Some individuals are genetically immune to a
- They pass these genes to their offspring
• Pesticides stop being effective
- Pesticide treadmill = chemists increase chemical
toxicity to compete with resistant pests
• Pesticides also kill nontarget organisms
- Including predators and parasites of pests
- Pest populations become harder to control
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Pesticide resistance
• Over 556 insect species are resistant to 300 pesticides
- Weeds and plant diseases have evolved resistance
to pesticides
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Biological control (biocontrol)
• Biological control = uses a
pest’s predators to control
the pest
- Reduces pest populations
without chemicals
- Reduces chemical use
• Cactus moths control prickly
• Bacillus thuringiensis (Bt)
= soil bacteria that kills
many pests
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Biocontrol agents may become pests
• It is risky to introduce an organism from a foreign
ecosystem into a new ecological context
- The effects of an introduced species are unpredictable
• The agent may have “nontarget” effects on the
environment and surrounding economies
- Cactus moths are eating rare Florida cacti
• Removing a biocontrol agent is harder than halting
pesticide use
- Biocontrol use must be carefully planned and
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Integrated Pest Management (IPM)
• Techniques to suppress pests:
- Biocontrol
- Chemicals, if necessary
- Population monitoring
- Habitat alteration
- Crop rotation and
transgenic crops
- Alternative tillage methods IPM in Indonesia
increased rice yields 13%
- Mechanical pest removal
and saved $179 million/yr
in phased-out subsidies
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We depend on insects to pollinate crops
• Not all insects are pests; some are absolutely vital
- 800 crop species rely on insect pollinators
• Pollination = male plant sex cells fertilize female sex
- By wind or animals
• Pollinators include:
- Hummingbirds
- Bats
- Insects (bees, wasps, etc.)
Flowers are evolutionary adaptations to attract pollinators
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Conservation of pollinators is vital
Bees pollinate over 100 crops
and contribute $15 billion in
• Populations of pollinators (e.g., bees) have plummeted
• Colony collapse disorder = entire beehives have
- Unknown causes—Insecticides? Parasites? Stress?
• Reducing or eliminating pesticide use and planting
flowering plants will help preserve bees
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Genetically modified organisms
• Genetic engineering =
laboratory manipulation of
genetic material
- Add, delete, modify DNA
• Genetically modified (GM)
organisms = organisms that
have been genetically
engineered by …
• Recombinant DNA = DNA
created from multiple
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Biotechnology is impacting our lives
• Biotechnology = the application of biological science to
create products derived from organisms
• Transgenic organism = an organism that contains DNA
from another species
- Transgenes = the genes that have moved between
• Biotechnology has created medicines, cleaned up
pollution, and dissolved blood clots
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Some genetically modified foods
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Genetic engineering versus agricultural
• Traditional breeding = changes organisms through
selective breeding of the same or similar species
- Works with organisms in the field
- Genes come together on their own
- Uses the process of selection
• Genetic engineering = mixes genes of different species
- Works with genetic material in the lab
- Directly creates novel combinations of genes
- Resembles the process of mutation
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Biotechnology is changing our world
• GM foods are a big business
• Most GM crops are herbicide
and pesticide resistant
- Large-scale farmers grow
crops more efficiently
- Most U.S. corn, soybeans,
cotton, and canola are
genetically modified
Globally, 14 million farmers grew
GM foods on 134 million ha
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What are the impacts of GM crops?
• As GM crops expanded, scientists, citizens, and
policymakers became concerned
- Impacts on human health
• Concerns over escaping transgenes
- They could harm nontarget organisms
- Pests could evolve resistance
- They could ruin the integrity of native ancestral
races and interbreed with closely related wild
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Genetic engineering has benefits and risks
• Environmental benefits of genetic engineering:
- Reduced use of chemical insecticides
- Increased no-till farming
- Decreased irrigation, deforestation, land conversion
• Negatives of genetic engineering:
- Increased herbicide use affects health and habitats
- Some GM fields support less biodiversity
• Precautionary principle = don’t undertake a new
action until the effects of that action are understood
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The GM debate involves ethics
• People don’t like “tinkering” with the food supply
• With increasing use, people are forced to use GM
products, or go to special effort to avoid them
• Multinational corporations threaten the small farmer
• Research is funded by corporations that profit if GM
foods are approved for use
• GM crops have not eradicated hunger
- GM crops do not focus on increased nutrition,
drought tolerance, etc.
The GM industry is driven by market considerations
driven by financial interests of corporations
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GMO producers are suing farmers
Corporations go to great lengths to
protect their GM investments
• Monsanto has launched 112 lawsuits against 372
farmers, winning an average $385,000 per case
- Monsanto sued Percy Schmeiser of Canada for
using its GM seeds without paying for them
- Schmeiser said the seeds blew onto his field from
adjacent fields
- The courts sided with Monsanto, saying that
Schmeiser had violated Monsanto’s patent
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The future of GM foods
• Europeans demand that GM foods are labeled
• U.S. consumers have mostly accepted GM crops
- They don’t realize most food contains GM products
• The U.S. sued the European Union before the World
Trade Organization for hindering free trade
• The Cartagena Protocol on Biosafety lays out
guidelines for open information about exported crops
- The U.S. has not joined
• Brazil, India, and China approve GM crops
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Consumption of animal products is growing
• As wealth and commerce increase, so does meat,
milk, and egg consumption
• Since 1950, global meat production has increased
fivefold and per capita meat consumption has doubled
Domestic animals raised for food increased from 7.2
billion in 1961 to 24.9 billion in 2008
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Our food choices are also energy choices
• Eating meat is far less energy
efficient than eating crops
• 90% of energy is lost from
one trophic level to the next
• Eating lower on the food
chain feeds more people
• Some animals convert grain
into meat more efficiently
than others
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Environmental ramifications of eating
• Land and water are
needed to raise food for
• Producing eggs and
chicken meat requires
the least space and water
- Producing beef
requires the most
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Resources needed for livestock production
When we choose what to
eat, we choose how we use
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Feedlot agriculture
• Feedlots (factory farms) =
also called Concentrated
Animal Feeding Operations
• Huge warehouses or pens
deliver food to animals living
at extremely high densities
- Over half of the world’s
pork and most of its
U.S. farms house hundreds of thousands of
debeaked chickens in crowded cages
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High consumption leads to feedlot
• Traditional agriculture keeps livestock on grasslands
• Feedlot animals are fed grain grown on cropland
- One-third of the world’s cropland is fed to livestock
• Feedlot agriculture allows economic efficiency
- Greater production of food
- Unavoidable in countries with high meat
consumption, like the U.S.
• Reduced grazing impacts on the land
- Manure can be applied to fields as fertilizer
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Livestock agriculture pollutes water and air
• Feedlots produce huge amounts of manure and urine
- Causing eutrophication
- Waterborne pathogens sicken people
• Crowded, dirty housing causes outbreaks in disease
- Heavy use of antibiotics, hormones, heavy metals
- Chemicals are transferred to people
- Microbes evolve resistance to antibiotics
• Air pollution: odors, ammonia (acid rain)
- More greenhouse gases (CO2, methane, nitrous
oxides) than automobile emissions
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We raise fish on “fish farms”
• World fish populations are
- Technology and
increased demand
• Aquaculture = raising
aquatic organisms in a
controlled environment
- Species are raised in
open-water pens or
land-based ponds
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Aquaculture is growing rapidly
• Over 220 freshwater and
marine species are grown
• The fastest-growing type
of food production
- Provides ¾ of the
world’s fish, ½ of the
- Most widespread in
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The benefits and drawbacks of
• Drawbacks:
• Benefits:
- A reliable protein source
- Diseases require
expensive antibiotics
- Can be sustainable
- Lots of waste
- Reduces pressure on
overharvested wild fish
- Uses grain
- Energy efficient
- Escaped GM fish
introduce disease or
outcompete wild fish
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Sustainable agriculture
• Industrial agriculture may seem necessary
- But less-intensive agricultural methods are better
• Sustainable agriculture = does not deplete soil,
pollute water, or decrease genetic diversity
• Low-input agriculture = uses smaller amounts of
pesticide, fertilizers, growth hormones, water, and
fossil fuels than industrial agriculture
• Organic agriculture = uses no synthetic fertilizers,
insecticides, fungicides, or herbicides
- Relies on biological approaches (e.g., composting
and biocontrol)
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Organic approaches reduce inputs and
• Organic Food Production Act (1990)
establishes national standards for organic
- The USDA issued criteria in 2000 by
which food could be labeled organic
• Some states pass even stricter guidelines
for labeling
- California, Washington, Texas
• Nearly 500 organizations offer
certification services
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The benefits of organic farming
• Farmers have lower input costs, enhanced income,
reduced chemical pollution, and soil degradation
- They practice stewardship to the land
- Obstacles include risks and costs of switching to
new methods
• Consumers are concerned about pesticide’s health risks
- They want to improve environmental quality
- Obstacles include the higher price of organics
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Organic agriculture is booming
• Organic farmers can’t keep
up with demand
- U.S. consumers pay
$22.9 billion/year
• Production is increasing
- 1.8 million ha in the U.S.
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Governments can support organic farming
• In 1993, the European Union adopted a policy
supporting farmers financially during conversion to
organic farming
• The U.S. offers no support so organic production lags
- The 2008 Farm Bill gives $112 million over 5
years for organic agriculture
- Many farmers can’t switch, because they can’t
afford the temporary loss of income
- In the long run, organic farming is more profitable
than conventional farming
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Locally supported agriculture is growing
• Sustainable agriculture reduces fossil fuel use from
long-distance transport of products
- Food is chemically treated for freshness and color
• Farmers’ markets = provide fresh, locally grown
• Community-supported agriculture (CSA)
- Consumers pay farmers
in advance
- Consumers get fresh food
- Farmers get a guaranteed
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Sustainable agriculture mimics natural
• Ecosystems operate in cycles
- Stabilized by negative feedback loops
• Small-scale Japanese farmers add ducks
to rice fields
- Ducks eat weeds, insects, snails
- Their waste is fertilizer
- Their paddling oxygenates
the water
- Fish and ferns provide food
and habitat
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• Industrialized agriculture has relieved pressures on
the land
- But the environmental consequences are severe
• To support 9 billion humans, we must shift to
sustainable agriculture
- Biological pest control, organic agriculture
- Pollinator protection, preservation of native crops
- Aquaculture
- Careful, responsible genetic modification of food
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Which statement is true?
a) We have become more sustainable in food
b) We can convert much more land to agricultural
c) Technology in the form of fossil fuels, pesticides and
fertilizers has increased production.
d) Population growth has exceeded food production in
recent decades.
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Which term describes the condition when a person
receives fewer calories than he or she needs?
Food security
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Which of the following is NOT correct about the
Green Revolution?
It dramatically increased food production.
It most benefits poor farmers.
It uses large amounts of fertilizers and pesticides.
It prevented starvation of millions of people.
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Which of the following is NOT a problem with using
Many species can become resistant to pesticides.
Offspring of resistant species are also resistant.
Pesticides kill many non-target species.
All are problems involved in using pesticides.
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Which statement about GM food production is NOT
It mixes genes from different organisms.
It mimics natural selection.
It involves working with genetic material in the lab.
Producing GM foods is a big business.
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Which statement is NOT correct about factory farming?
a) It is far more energy efficient than eating grains.
b) Some species convert grain into meat more
efficiently than other species.
c) Much of the world’s grain is fed to livestock.
d) More livestock can be produced in an area.
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Sustainable agriculture:
Uses concentrated animal feeding operations.
Maximizes use of fertilizers and pesticides.
Does not deplete soil or pollute water.
Is currently not a feasible solution.
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QUESTION: Weighing the Issues
The green revolution has increased crop yields, but
only by increasing fertilizers, pesticides, irrigation
and hybrid seed. Do you consider it a success?
Yes, because more people were fed, regardless
of the price.
Yes, because industrialized countries can help
through education and technology.
No, we will eventually pay the environmental
costs of producing food in this way.
It does not matter, I can buy food whenever I
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QUESTION: Weighing the Issues
Factory farming allows us to have lots of meat products.
But the animals are often kept in undesirable, stressful
the conditions. Should the quality of the animals’ lives
be considered when we decide how to raise food?
a) Yes, the quality of an animal’s life is important, too.
b) Yes, but only if it does not interfere with access to
c) No, animals have no right to a quality of life.
d) I don’t care, I’m not fond of cows or chickens.
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QUESTION: Interpreting Graphs and Data
If a person eats 3 kg of meat per week, how many kg of
grain are required if the meat came from a pig?
60 kg
22 kg
3 kg
12 kg
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QUESTION: Interpreting Graphs and Data
What does this graph show about sales of organic
food in the United States?
a) Sales increased slowly
b) Sales increased but
not the dollar amounts
c) Acreage has declined
in the past years
d) Sales, dollar amounts,
and acreage increased
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