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
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
crops
•
The agrobiotech industry
questioned these findings
Today, we are producing more food per person
•
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
By 2050, we will have to
feed 9 billion people
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
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
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
Malnutrition can lead to diseases
•
Kwashiorkor
= diet lacks
protein or essential amino
acids
-
Occurs when children stop
breast
-
feeding
-
Bloated stomach, mental
and physical disabilities
•
Marasmus
= protein deficiency
and insufficient calories
-
Wasting or shriveling of the
body
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
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
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
Monocultures increase output, but at a cost
•
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
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
Preserving crop diversity: insurance against failure
•
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
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
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
Pests evolve resistance to pesticides
•
Some individuals are
genetically immune to a
pesticide
-
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
Pesticide resistance
•
Over 556 insect species are resistant to 300
pesticides
-
Weeds and plant diseases have evolved resistance
to pesticides
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
pear
•
Bacillus thuringiensis
(Bt)
=
soil bacteria that kills many
pests
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
regulated
Integrated Pest Management (IPM)
•
Techniques to suppress
pests:
-
Biocontrol
-
Chemicals, if necessary
-
Population monitoring
-
Habitat alteration
-
Crop rotation and
transgenic crops
-
Alternative tillage
methods
-
Mechanical pest removal
IPM in Indonesia
increased rice yields 13%
and saved $179 million/yr
in phased
-
out subsidies
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
cells
-
By wind or animals
•
Pollinators include:
-
Hummingbirds
-
Bats
-
Insects (bees, wasps, etc.)
Flowers are evolutionary adaptations to attract pollinators
Conservation of pollinators is vital
•
Populations of pollinators (e.g., bees) have plummeted
•
Colony collapse disorder = entire beehives have
vanished
-
Unknown causes
—
Insecticides? Parasites? Stress?
•
Reducing or eliminating pesticide use and planting
flowering plants will help preserve bees
Bees pollinate over 100 crops
and contribute $15 billion in
services/year
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
organisms
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
organisms
•
Biotechnology has created
medicines, cleaned up
pollution, and dissolved
blood clots
UTSA Biotechnology Building
Some genetically modified foods
Genetic engineering versus agricultural breeding
•
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
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
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 plants
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
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
GMO producers are suing farmers
•
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
Corporations go to great lengths to
protect their GM investments
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
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
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
Environmental ramifications of eating meat
•
Land and water are
needed to raise food for
livestock
•
Producing eggs and
chicken meat requires
the least space and
water
-
Producing beef
requires the most
Resources needed for livestock production
When we choose what to
eat, we choose how we
use resources
Feedlot agriculture
•
Feedlots
(
factory farms
) =
also called
Concentrated
Animal Feeding Operations
(
CAFOs
)
•
Huge warehouses or pens
deliver food to animals living
at extremely high densities
-
Over half of the world’s
pork and most of its
poultry
U.S. farms house hundreds of thousands of
debeaked
chickens in crowded cages
High consumption leads to feedlot agriculture
•
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
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 (CO
2
,
methane, nitrous oxides) than
automobile emissions
MRSA origin
We raise fish on “fish farms”
•
World fish populations are
plummeting
-
Technology and
increased demand
•
Aquaculture
= raising
aquatic organisms in a
controlled environment
-
Species are raised in
open
-
water pens or
land
-
based ponds
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
shellfish
-
Most widespread in
Asia
The benefits and drawbacks of aquaculture
•
Benefits:
-
A reliable protein source
-
Can be sustainable
-
Reduces pressure on
overharvested wild fish
-
Energy efficient
•
Drawbacks:
-
Diseases require
expensive antibiotics
-
Lots of waste
-
Uses grain
-
Escaped GM fish
introduce disease or
outcompete wild fish
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
)
Organic approaches reduce inputs and pollution
•
Organic Food Production Act (1990)
establishes national standards for organic
products
-
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
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
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.
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
Soil
Retention
Natural
Fertilization
Higher
Nutrition
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 food
•
Community
-
supported agriculture
(CSA)
-
Consumers pay farmers
in advance
-
Consumers get fresh food
-
Farmers get a guaranteed
income
Sustainable agriculture mimics natural ecosystems
•
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
Conclusion
•
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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