Transcript Soil and Agriculture - Liberty Union High School District

Thursday, November 3rd, 2016
 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).
 Genetic
engineering
involves splicing a
gene from one
species and
transplanting the DNA
into another species.
Figure 13-19
 The
winged bean, a
GMF, could be grown to
help reduce
malnutrition and the
use of large amounts of
inorganic fertilizers.
Figure 13-20
 GMO-
scientists directly alter the genes of
organisms including crop plants and livestock
• In the past we’ve used artificial selection/selective
breeding
 GM
crops are modified to be-
• Herbicide resistant so farmers can spray herbicide on
weeds w/o killing their crops
• Pest resistant
• Ice resistant (strawberries)
 GM
foods are a big business
 Globally in 2012, 17 million farmers grew GM
foods on 170 million ha (420 million acres)—
11% of all cropland
• 90% of U.S. corn, soybean, cotton, and canola are GM
plants
 Most
GM crops are herbicide and pesticide
resistant
• Large-scale farmers grow crops more efficiently
 Traditional
breeding changes organisms
through selective breeding of the same or
similar species
• Works with entire 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
 Controversy
has arisen
over the use of
genetically modified food
(GMF).
• Critics fear that we know too
little about the long-term
potential harm to human
and ecosystem health.
 There
is controversy over
legal ownership of
genetically modified crop
varieties and whether
GMFs should be labeled.

As GM crops expanded, scientists, citizens, and policymakers
became concerned
• Impacts on human health, but support of this has been elusive

Ecological concerns over escaping transgenes
• They could harm non-target organisms
• Pests could evolve resistance
• They could ruin the integrity of native ancestral races and
interbreed with closely related wild plants

Precautionary principle = idea that one shouldn’t undertake a
new action until the effects of that action are understood
 Concerns of GM crops include
• GM plants could breed with the wild
variety found in nature = decrease in
plant diversity
• GM plants could create “superpests”
resistant to the GM “supercrops”
• Consequences of GM crops are still
open for debate because it is newer
technology
 Concern about possibly impacting human
health w/ altered proteins
 Supports
of GM crops claim they reduce
carbon emissions by:
• Fewer pesticide applications = tractors using less fuel
• Herbicide resistant crops encourage no-till farming
then more carbon is sequestered in the soil
 GM
crop research suggests that GM crops
reduced carbon emissions equivalent to taking
3.6 million cars off the road
 Environmental
Benefits:
• Higher yields
• Promotes low-tillage techniques
 Decrease soil erosion
 Decrease energy consumption from machinery
• Lower fertilizer requirement
• Reduce pesticide use
• Drought resistance crops reduce irrigation needs
 Economic
Benefits:
• Produces higher yeilds
• Less money spent on pesticide, herbicide, fertilizer,
water
• Increased nutritional value
• Low tillage techniques:
 Lower fossil fuels needed and released
• Less pesticide/herbicide use = decrease healthcare
costs for farmers
 Environmental
Disadvantages:
• Insect resistant crops could reduce beneficial insects
• Drought resistant and salinity resistant plants increases
pressure to convert semi-arid land into farmland =
decrease in biodiversity in those areas
• Lower genetic variability
 Wheat varieties in China have dropped from 10,000 in 1949
to 1,000 by 1970
 Economic
Disadvantages
• Higher yields = increase in soil
depletion
• Produces sterile seeds
 Have patent seeds which must be
purchased annually (poor farmers
unable to purchase)
• Cost of tracking and labeling GM
crops in food supply
• Research and development
 Consumers
in Europe have expressed widespread
unease about genetic engineering
• U.S. consumers have largely accepted GMOs
 Europe
blocked import of American agricultural
products from 1998 to 2003 because of concerns
about the products being genetically modified
• The United States 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
Some nations now demand that GM foods be labeled
 United States Senate just voted in June 2016 to require
labeling

• Large majority of Americans would like labeling
• Some loopholes are present
Labeling proponents: people have a right to know what they
are eating
 Labeling opponents: labeling implies that the food is
dangerous
 In countries where food is labeled, some products stopped
being stocked due to consumer aversion
