Transcript Food Production Notes Complete - Mercer Island School District

Food Production
Macronutrients- carbohydrates, proteins and fats
Micronutrients- vitamins (A, C, E) and minerals (iron, iodine,
calcium)
Chronic undernutrition: not getting an adequate amount of
calories
Chronic malnutrition: deficiency of key nutrients
Has been an improvement in the number of people facing
chronic undernutrition around the world.
But in developing world 1 in 6 people still suffer from chronic
undernutrition.
Green Revolution (starting in 1950’s)
• Selectively bred crops (also know as artificial
selection) with higher yields.
• Inorganic fertilizers
• Pesticides
• Genetically- engineered crops
Genetically Modified Organisms:
Also known as Transgenic Organisms or
Bioengineered Species
A biotechnology technique that allow genes from
different species to be inserted into an organisms
genome.
Example: Fish tomato
Tomato with gene from
flounder to reduce freezing.
Was never commercially
available
Basics of Recombinant DNA Technology
Gene splicing (joining two
different pieces of DNA) relies on
the use of restriction enzymes,
which are natural occurring
enzymes from bacteria whose
function in bacteria is to cut up
invading pieces of viral DNA.
Most restriction enzymes cut
DNA in a way that leaves single
stranded DNA ends (sticky ends).
The Process of Recombinant DNA
1.Both a vector such as a
plasmid and a gene of interest
are cut with the same
restriction enzyme.
2.The complimentary sticky
ends of the two different
pieces of DNA allow them to
be joined. DNA ligase forms
bond.
3.Recombinant plasmid
introduced into cell culture.
Examples of GMO crops
o Golden Rice: beta carotene gene
from daffodils inserted into rice
plants. Beta carotene can be
converted into Vitamin A in the
body.
o Round-up Ready (glyphosphate
resistant): Gene for resistant to the
herbicide is inserted to allow crops
to be sprayed with the herbicide.
o BT crops: Gene for natural
insecticide from bacteria Bacillus
thuringiensis is inserted into crops.
Genetically Modified Organisms
Projected
Disadvantages:
Projected
Advantages:
Higher yields due to
potential for improved
characteristics such as
resistance to insects,
disease, frost etc.
Improved quality of
crop due to new
characteristics: less
spoilage etc.
Irreversible and
unpredictable
ecological effects.
New allergens in foods
Increase in pesticideresistant insects,
herbicide- resistant
weeds etc.
Can harm beneficial
insect
Lower genetic
diversity
Pesticide- general term for a substance that kills some
type of unwanted pest.
Types
Insecticide
Herbicide- kills weeds (plants)
Fungicide- kills fungi (blight, mold, mildews and
rusts)
Pesticides
1st Generation Pesticides- natural chemicals (esp. from plants)
2nd Generation Pesticides- starting with DDT in 1939
Broad-spectrum agent: Effective against a wide range of pests
But also kill beneficial species.
Chlorinated hydrocarbons: such as DDT, dieldrin
- persistent
- biomagnfy
Organophosphates:such as malathion and parathion
- not persistent and do not biomagnify
- but are highly toxic
Narrow-spectrum agents: toxic to a more selective group of
organisms.
Conventional Chemical Pesticides
Advantages:
Disadvantages:
Save lives
Kill natural pest
(decreased malaria)
enemies
Increased food
Can harm wildlife
supply
and people
Can promote
genetic resistance
Expensive to
farmers- and cost
can increase
(pesticide
treadmill)
The pesticide neonictinoid is suspected to be a primary cause
of the bee colony collapse epidemic.
Pesticide Treadmill
Because:
• a pesticide may kill beneficial insects that
would decrease pest population
• Pests may develop resistance to pesticide
Farmers often need to add increasing amounts
of pesticide for it be effective.
Pesticide Regulations
Federal Insecticide and Fungicide Regulation Act (FIFRA),
1972
Overseen by EPA, USDA and FDA.
EPA to assess new pesticides, but inadequate funds
Food Quality Protection Act, 1996
Reduce levels of pesticide residues if inadequate
information on pesticide’s safety.
Alternatives to Pesticides
• Pheromone Traps:
Sticky traps with pheromones (chemical
messages released by organism for
mating signals or other communication)
can be used to lure pests.
• Cultural Practices: “Fool the pest”
- rotation of crops
• Biological controls such as beneficial
insects
-Homes for pest enemies
• Hormones to disrupt pest life cycle
Integrated Pest Management:
- Combination of cultural,
biological and chemical tools
- Monitoring of pests at
economically tolerable level
-
Doesn’t use broad spectrum
pesticides
Brazil reduced pesticide usage
by 90% using IPM