10 - Personal

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14 Δεκ 2012 (πριν από 4 χρόνια και 6 μήνες)

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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