Transcript Chapter 13 - apeswstes

Chapter 23
Food Production and
Pest Management
Biodiversity Loss
Soil
Water
Air Pollution
Human Health
Nitrates in
drinking water
Loss and
degradation of
grasslands,
forests, and
wetlands
Erosion
Water waste
Loss of fertility
Aquifer depletion
Greenhouse gas
emissions from
fossil fuel use
Salinization
Increased runoff and
flooding from cleared
land
Pesticide residues
Other air pollutants in drinking water,
from fossil fuel use food, and air
Fish kills from
pesticide runoff
Desertification
Waterlogging
Killing wild predators to
protect livestock
Loss of genetic diversity of
wild crop strains replaced
by monoculture strains
Sediment pollution from
erosion
Fish kills from pesticide
runoff
Greenhouse gas
emissions of
nitrous oxide from
use of inorganic
fertilizers
Surface and groundwater
pollution from pesticides
and fertilizers
Belching of the
greenhouse gas
Overfertilization of
methane by cattle
lakes and rivers from
runoff of fertilizers,
livestock wastes, and
Pollution from
food processing wastes pesticide sprays
Contamination of
drinking and
swimming water
with disease
organisms from
livestock wastes
Bacterial
contamination of
meat
Fig. 13-18, p. 285
THE GREEN REVOLUTION AND ITS
ENVIRONMENTAL IMPACT
 Modern
agriculture has a greater harmful
environmental impact than any human
activity.
 Loss of a variety of genetically different crop
and livestock strains might limit raw material
needed for future green and gene
revolutions.

In the U.S., 97% of the food plant varieties
available in the 1940 no longer exist in large
quantities.
THE GENE REVOLUTION
 To
increase crop yields, we can mix the
genes of similar types of organisms and mix
the genes of different organisms.


Artificial selection has been used for centuries to
develop genetically improved varieties of crops.
Genetic engineering develops improved strains
at an exponential pace compared to artificial
selection.
 Controversy
has arisen over the use of
genetically modified food (GMF).
Mixing Genes
 Genetic
engineering
involves splicing a
gene from one
species and
transplanting the
DNA into another
species.
Figure 13-19
Genetically Modified Food
Should we fear or embrace it?
Which salmon do you want for dinner?
/
Selective Breeding

For thousands of
years, plant and
animals with
favorable traits have
been bred to
perpetuate these
traits in offspring.
• Canines have been selectively
bred to help humans
Selective Breeding
• Teosinite is a large wild
grass that grows in Mexico
and is the closest living
relative to corn
• Corn was domesticated
>8,700 years ago and
probably looked similar to
teosinite
Genetic engineering


All genetic variation
is due to random
genetic mutations
In time, humans
began using more
sophisticated
breeding practices
such as mutation
breeding
• Organisms are exposed to
chemicals or radiation with
the hopes of producing
new genetic traits , such as
the ruby red grapefruit
Genetic engineering

We are now able to
physically
manipulate the
genes of organisms
 For example,
genes from one
• FLAVR SAVRTM Tomato was 1st GM
organism can be
food approved safe by the FDA
placed into another • It was intended to have a longer
shelf life
organism
Gene silencing
•
Some genetically modified
organisms do not contain a
foreign gene
• instead engineering allows
scientists to “turn off”
normally expressed genes
• Scientists remove gene
and reinsert it in the wrong
direction forming nonsense • Gene silencing has
mRNA
been used to reduce
the amount of caffeine
in some coffee beans
Advantages of genetic engineering
Plants
• Pest resistance
• Virus resistance
• Increased crop yields
and longer shelf life
• Environmental
tolerance (able to
withstand drought,
extreme
temperatures, etc.)
Other organisms
• Faster growth rates
• Increased body mass
• Ability to produce
valuable proteins in
animal milk
Pest resistance
 Insects
can
damage crops
 Many insecticides
from the past have
negative
environmental
consequences
(DDT)
 Modern
insecticides safer,
• Regular corn in left
destroyed by corn
borer
• Bt corn from same
field on right
Neutraceuticals
•
Adding or increasing vitamin
or mineral contents,
modifying fats and oils, and
altering starch and sugar
quantities
• Benefit consumer rather
than farmer
• Examples: Golden Rice,
potatoes modified to convert
more starch into glucose,
oils that are healthier,
decaffeinated coffee
• Golden rice was developed
using daffodil and soil
bacterium genes to provide
beta-carotene to people in
developing countries
Pharmaceuticals “Pharming”



Placing vitamins and other
essential nutrients into food
Very similar to neutraceuticals
Edible vaccines could be used in
developing countries to increase
vaccinate rates
Future Developments
• Transgenic cows making blood proteins for
hemophiliacs or lactoferrin for infant formula
• Pigs developed to provide organs for human
transplant
Environmental Tolerance
 Plants
are being developed that can
withstand:
 High salinity
 Drought
 Frost
Concerns of genetic engineering
• Cross-pollination
• Ecosystem disruption
• Evolution of
“superweeds”
• Allergens transferred
to new foods
• Unknown long-term
health effects
• Inadequate regulation
Have problems arisen?
Pioneer Hi-Bred
wanted to boost the
nutritional value of its
soy-based animal feed.
It developed GM
soybeans containing
2S albumin, a protein
from Brazil nuts.
2S albumin is a human
allergen, and the
allergen was transferred
into the beans.
The soybeans were intended
only for animal consumption,
but Pioneer’s soybeans were
not released for use.
Have problems arisen?
 No
individuals have been made sick from
genetically modified food
 Genes have escaped and hybridized with
wild relatives up to 13 miles away
PRODUCING MORE MEAT
 About
half of the world’s meat is produced by
livestock grazing on grass.
 The other half is produced under factory-like
conditions (feedlots).

Densely packed livestock are fed grain or fish
meal.
 Eating
more chicken and farm-raised fish and
less beef and pork reduces harmful
environmental impacts of meat production.
CATCHING AND RAISING MORE
FISH AND SHELLFISH
 After
spectacular increases, the world’s total
and per capita marine and freshwater fish
and shellfish catches have leveled off.
Figure 13-23
Trade-Offs
Aquaculture
Advantages
High efficiency
High yield in
small volume
of water
Can reduce
overharvesting
of conventional
fisheries
Low fuel use
High profits
Profits not tied
to price of oil
Disadvantages
Needs large inputs
of land, feed, and
water
Large waste
output
Destroys
mangrove forests
and estuaries
Uses grain to feed
some species
Dense populations
vulnerable to
disease
Tanks too
contaminated to
use after about 5
years
Fig. 13-24, p. 292
Government Policies and Food
Production
 Governments
use three main approaches to
influence food production:



Control prices to keep prices artificially low.
Provide subsidies to keep farmers in business.
Let the marketplace decide rather that
implementing price controls.
SOLUTIONS: MOVING TOWARD
GLOBAL FOOD SECURITY
 People
in urban areas
could save money by
growing more of their
food.

Urban gardens provide
about 15% of the
world’s food supply.
 Up
to 90% of the
world’s food is wasted.
Figure 13-26
CATCHING AND RAISING MORE
FISH AND SHELLFISH
 Government
subsidies given to the fishing
industry are a major cause of overfishing.



Global fishing industry spends about $25 billion
per year more than its catch is worth.
Without subsidies many fishing fleets would have
to go out of business.
Subsidies allow excess fishing with some
keeping their jobs longer with making less
money.
Aquaculture: Aquatic Feedlots
 Raising
large numbers of fish and shellfish in
ponds and cages is world’s fastest growing
type of food production.
 Fish farming involves cultivating fish in a
controlled environment and harvesting them
in captivity.
 Fish ranching involves holding anadromous
species that live part of their lives in
freshwater and part in saltwater.

Fish are held for the first few years, released,
and then harvested when they return to spawn.
Solutions: Steps Toward More
Sustainable Food Production
 We
can increase food security by slowing
populations growth, sharply reducing poverty,
and slowing environmental degradation of the
world’s soils and croplands.
PROTECTING FOOD RESOURCES:
PEST MANAGEMENT
 Organisms
found in
nature (such as
spiders) control
populations of most
pest species as part
of the earth’s free
ecological services.
Figure 13-27
PROTECTING FOOD RESOURCES:
PEST MANAGEMENT
 We
use chemicals to repel or kill pest
organisms as plants have done for millions of
years.
 Chemists have developed hundreds of
chemicals (pesticides) that can kill or repel
pests.


Pesticides vary in their persistence.
Each year > 250,000 people in the U.S. become
ill from household pesticides.
PROTECTING FOOD RESOURCES:
PEST MANAGEMENT
 Advantages
and disadvantages of conventional
chemical pesticides.
Figure 13-28
Individuals Matter: Rachel Carson
 Wrote
Silent Spring
which introduced the
U.S. to the dangers
of the pesticide DDT
and related
compounds to the
environment.
Figure 13-A
The ideal Pesticide and the
Nightmare Insect Pest
 The
ideal pest-killing chemical has these
qualities:




Kill only target pest.
Not cause genetic resistance in the target
organism.
Disappear or break down into harmless
chemicals after doing its job.
Be more cost-effective than doing nothing.
Superpests
 Superpests
are
resistant to
pesticides.
 Superpests like the
silver whitefly (left)
challenge farmers
as they cause >
$200 million per
year in U.S. crop
losses.
Figure 13-29
Pesticide Protection Laws in the U.S.
 Government
regulation has banned a number
of harmful pesticides but some scientists call
for strengthening pesticide laws.


The Environmental Protection Agency (EPA), the
Department of Agriculture (USDA), and the Food
and Drug Administration (FDA) regulate the sales
of pesticides under the Federal Insecticide,
Fungicide and Rodenticide Act (FIFRA).
The EPA has only evaluated the health effects of
10% of the active ingredients of all pesticides.
What Can You Do?
Reducing Exposure to Pesticides
• Grow some of your food using organic methods.
• Buy organic food.
• Wash and scrub all fresh fruits, vegetables, and wild foods you pick.
• Eat less or no meat.
• Trim the fat from meat.
Fig. 13-30, p. 299
Other Ways to Control Pests
 There
are cultivation, biological, and
ecological alternatives to conventional
chemical pesticides.






Fool the pest through cultivation practices.
Provide homes for the pest enemies.
Implant genetic resistance.
Bring in natural enemies.
Use pheromones to lure pests into traps.
Use hormones to disrupt life cycles.
Other Ways to Control Pests
 Biological
pest
control: Wasp
parasitizing a
gypsy moth
caterpillar.
Figure 13-31
Other Ways to Control Pests
 Genetic
engineering can
be used to
develop pest and
disease resistant
crop strains.
 Both
tomato plants were exposed to
destructive caterpillars. The genetically
altered plant (right) shows little damage.
Figure 13-32
Case Study: integrated Pest
Management: A Component of
Sustainable Agriculture
 An
ecological approach to pest control uses a
mix of cultivation and biological methods, and
small amounts of selected chemical
pesticides as a last resort.

Integrated Pest Management (IPM)
Case Study: integrated Pest
Management: A Component of
Sustainable Agriculture
 Many
scientists urge the USDA to use three
strategies to promote IPM in the U.S.:



Add a 2% sales tax on pesticides.
Establish federally supported IPM demonstration
project for farmers.
Train USDA personnel and county farm agents in
IPM.
 The
pesticide industry opposes such
measures.
What does organic mean?
Conventional farmers
Organic farmers
Apply chemical fertilizers to
promote plant growth.
Apply natural fertilizers, such as
manure or compost, to feed soil
and plants.
Spray insecticides to
reduce pests and disease.
Use beneficial insects and birds,
mating disruption or traps to
reduce pests and disease.
Use chemical herbicides
to manage weeds.
Rotate crops, till, hand weed or
mulch to manage weeds.
Give animals antibiotics,
growth hormones and
medications to prevent
disease and spur growth.
Give animals organic feed and
allow them access to the
outdoors. Use preventive
measures — such as rotational
grazing, a balanced diet and
clean housing — to help minimize
disease.
SOLUTIONS: SUSTAINABLE
AGRICULTURE
 Three
main ways to reduce hunger and
malnutrition and the harmful effects of
agriculture:



Slow population growth.
Sharply reduce poverty.
Develop and phase in systems of more
sustainable, low input or organic agriculture over
the next few decades.
Sustainable
Agriculture
 Results
of 22
year study
comparing
organic and
conventional
farming.
Figure 13-34
The use of nitrogen based fertilizers in the
Mid-western U.S. is a major contributing
factor to which of the following?
a.
b.
c.
d.
e.
Spread of West Nile virus
Hypoxia in the Gulf of Mexico
Water shortages in communities near the
Great Lakes
Soil erosion in Texas
The increase in severe storms in the
Southeastern U.S.
Biological controls are frequently used to replace
persistent chemical pesticides. Which of the
following represents the greatest potential risk
of using biological controls?
a. The control agents attacks not only its
intended target but also beneficial species.
b. The control agent mutates and is no longer an
effective control.
c. Repeated applications or introductions are
required to eliminate the pest population.
d. Residual pesticides in the environment kill the
control agent before it can eradicate the pest.
e. Biological controls prove to be more costly to
use than chemical pesticides.
Which type of soil
contains:
30%clay, 30% silt,
40% sand?
a.
b.
c.
d.
e.
Clay
Loam
Clay loam
Silty clay loam
Sandy Clay loam
Which of the following is true of farm-raised
salmon?
a.
b.
c.
d.
e.
They are more genetically diverse than
their wild counterparts.
They seldom escape from their
containment areas.
They have no impact on the quality of the
water in which they are raised.
They are often infected with parasites
and sea lice.
They are maintained at lower population
densities than are wild salmon.
Which of the following is the best illustration
of a pesticide treadmill?
a.
b.
c.
d.
e.
Sequence of several pesticides used by
farmers to maximize effectiveness
Increased used of pesticides to eradicate
genetically resistant pests
Biomagnification of pesticides in the fatty
tissue of primary consumers
Movement of pesticides following their
percolation into the groundwater
Process that is used to manufacture
pesticides
The development of dangerous strains of disease
organisms represents a significant
consequence of which of the following
agricultural practices?
a. Using herbicides in mechanized, large-scale
farming
b. Using plant-based insecticidal compounds on
vegetable crops
c. Growing crops that are genetically modified for
increased yields
d. Including the use of legumes into crop-rotation
protocols
e. Incorporating antibiotics into the feeding
regimens of densely concentrated livestock
Which of the following practices is consistent with
the production of organic crops according to
the U.S. Department of Agriculture?
a. Using sodium nitrate as a fertilizer on green,
leafy vegetables
b. Using strychnine to prevent buildup of aphid
populations in field crops
c. Using chemicals known as pheromones to
disrupt insect mating cycles
d. Using sewage sludge to improve the fertility
and structure of soil
e. Using genetically modified plant varieties that
kill insects that chew their leaves





Products certified 95 percent or more organic display the
USDA seal.
Products that are completely organic — such as fruits,
vegetables, eggs or other single-ingredient foods — are
labeled 100 percent organic and can carry a small USDA
seal. Foods that have more than one ingredient, such as
breakfast cereal, can use the USDA organic seal or the
following wording on their package labels, depending on the
number of organic ingredients:
100 percent organic. Products that are completely
organic or made of all organic ingredients.
Organic. Products that are at least 95 percent organic.
Made with organic ingredients. These are products that
contain at least 70 percent organic ingredients. The
organic seal can't be used on these packages
Solutions: Making the Transition to
More Sustainable Agriculture
 More
research,
demonstration
projects,
government
subsidies, and
training can
promote more
sustainable
organic
agriculture.
Figure 13-35