Transcript ch. 18-food and agriculture

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Food and Nutrition
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World Food Problems
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Principle Types of Agriculture
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Challenges of Producing More Crops and
Livestock
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Environmental Impact of Agriculture
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Solutions to Agricultural Problems
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Fisheries of the World
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Carbohydrates
 Sugars and starches metabolized by cellular
respiration to produce energy
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Proteins
 Large, complex molecules composed of amino
acids that perform critical roles in body. Must
get essential amino acids from food.
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Lipids
 Include fats and oils and are metabolized by
cellular respiration to produce energy. Most
energy.
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Vitamins (molecule) and Minerals (elements
– iron, calcium)
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Annual grain production (left) has increased
since 1970
Grain per person has not (right)
South Asia and Sub-Saharan Africa
 Growing population
 Rising temperatures
 Falling water tables
and droughts
 Ethanol production
 More grain is going
towards feeding
livestock.
▪ Ex: 1 kg of beef
requires 7 kg grain
VEGETARIANS
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More sustainable land
use
Harder to get
essential amino acids
Rice and beans = nutritious
Just rice = not nutritious
NON-VEGETARIANS
Easy source of protein
– meat, milk, eggs
 Livestock requires
more land, more
energy, more water
 Risk of heart disease
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Poverty and Food
 1.3 billion people are so poor they cannot
afford proper nutrition
 Undernourished vs. malnourished
▪ Kwashiokor – protein deficient
 More common in
▪ Rural than urban areas
▪ Infants, children and the elderly
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Economics and Politics
 Cost money to store, produce, transport
and distribute food
 Getting food to those who need it is political
Industrialized agriculture
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High-input
High yields
Fossil fuels:
machinery,
inorganic
fertilizers,
pesticides,
irrigation
HDC
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Subsistence Agriculture
 Low yields (enough for family)
 Energy from humans/work animals
 Require lots of land
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Examples:
 Shifting cultivation
 Slash and burn agriculture (deforestation)
 Nomadic herding
 No pesticides, synthetic fertilizers
genetically modified crops
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Domestication
 causes a loss of genetic diversity
▪ Farmer selects and propagates
plants/animals with desirable agricultural
characteristics
• Many high yielding
crops are genetically
uniform
• High likelihood that
bacteria, fungi, viruses,
etc. will attack and
destroy entire crop
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Increasing Crop Yield
•
Graph = wheat
Developed
countries:
• fertilizers
• Pesticides
• Selective
breeding
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1960s – more grain (wheat/rice) per
acre
Selective breeding
Use of fertilizers and irrigation made
it possible to grow crops in more
places
Started in Mexico, spread to US,
India, China
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Problems:
 High energy costs
▪ Require fossil fuels to make fertilizers,
build/run tractors, construct dams/canals,
pump water from groundwater
 Environmental degradation due to
inorganic fertilizers and pesticides
 Led to overpopulation
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4–
3–
21-
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CAFOs (concentrated animal feeding operations): less
land, but more antibiotics. Waste disposal
Increasing Livestock Yields:
 Antibiotics
▪ Problems with increased bacteria resistance
(evolution)
 Hormone supplements (rBGH)
▪ US and Canada do this: increase growth and milk
production.
▪ Europe does not citing human health concerns
(Precautionary Principle)
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High use of fossil fuels
 Air pollution
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Untreated animal wastes
and agricultural chemicals
 Water pollution
 Harms fisheries
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Insects, weeds, and
disease-causing organisms
developing resistance to
pesticides
 Contaminate food supply
 Kills beneficial soil organisms
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Land degradation
 Decreases future ability of land to support
crops or livestock
▪ Erosion – decreases soil fertility, sediments
pollute water
▪ Compacting soil, waterlogging, salinization
Habitat fragmentation, deforestation
 habitat loss
 erosion
 Decreases biodiversity and gene pool
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Cultivating
marginal lands
 Irrigating dry land
 Cultivating land
prone to erosion
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Water
consumption
 Ex: Ogallala Aquifer
= nonrenewable
resource b/c water
so old
 Drip irrigation!
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Examples:
 Pest control: natural Predator-prey
relationships instead of pesticides, crop
selection
 Reduce erosion: conservation tillage and
contour plowing
 Reduce fertilizers – crop rotation, animal
manure, supplying nitrogen with
legumes
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Integrated Pest Management (IPM)
 Limited use of pesticides by using
knowledge of the life cycles of pests,
pheromones, trapping, and then
targeted pesticide use;
allowing some pests is fine
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Organic agriculture
 No pesticides, synthetic fertilizers
genetically modified crops
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4 – I can cite at least 2 methods for
each of the farming issues below
3 – I can cite at least 1 method to
farm sustainably for each of the
following farming issues: pesticides,
synthetic fertilizers, erosion, soil
salinization, water consumption
2 - I know a few examples, but not
one for each issue.
1 – I know what sustainable means.
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Transferring genes of desirable trains from
one organism into the DNA of another
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Faster than selective breeding
1st GM food on market – Flavr Savr
Tomato
Typical goals
 Increase nutrition – ex: golden rice
 Pest resistance – ex: Bt corn
 Resistant to other environmental stress
– drought, salty or acidic soils
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GE in animals
 Create hormones to increase growth
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Determined safe by FDA
Concerns: allergies, reduced
biodiversity if introduced to wild
Labeling: none in US
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4 – I can explain the pros and cons
of GE food.
3 – I understand multiple reasons
why GE food is developed AND
multiple reasons why people are
concerned about it.
2 - I understand either why GE food
is developed or why people are
concerned about it, but not both.
1 – I know what GE food is.
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No nation lays claim
to open ocean
 susceptible to overuse
 Tragedy of the
Commons
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Overharvesting
 Many species are at point
of severe depletion
 Food for growing human
population
 Technological advances in
fishing gear
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Longlines –
thousands of hooks
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Purse-sein nets
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Trawl net – dragged
along the bottom
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Spotter airplanes
• Overfishing reduces gene
pool of existing fish
• By-catch DIE
 Magnuson-Stevens Fishery Conservation
and Management Act
▪ EX: Set quotas, limits # of boats
• Marine
Mammal
Protection
Act
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Ocean Pollution - dumping ground
 Oil
 Heavy metals
 Deliberate litter dumping
 Stormwater runoff from cities and
agricultural areas – biggest pollution
source
 Coastal areas degraded by development (many
fish depend on tidal marshes, mangrove
swamps, estuaries for spawning and feeding)
 Raising of aquatic organisms for human food
 Protein!!
 Negatives:
▪ Locations of fisheries may hurt natural habitats –
compete for shore space, destroy mangroves, destroy
breeding grounds for fish
▪ Produce waste that pollutes adjacent water
▪ Often fed fish from the wild
▪ Expensive facility
▪ Easy spread of disease  antibiotics
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4 – I can teach the next class.
3 – I understand at least 2 fishing
techniques that may lead to
overfishing, the laws that serve to
protect fisheries, and the pros and
cons of aquaculture.
2 – I understand but need to re-read
my notes.
1 – I know why overfishing is bad.