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10_00-CS.JPG. Ch. 10 Agriculture. Maize in Oaxaca, Mexico. Corn (maize) originated in Oaxaca, Mexico, 5,500 years ago Oaxaca – center for preservation of cultivars In 2001, transgenes from U.S. appeared in Oaxacan maize Disappeared?. Transgenic maize in Oaxaca. Teosinte. 10_01.JPG.
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10_00-CS.JPG Ch. 10 Agriculture Maize in Oaxaca, Mexico
Corn (maize) originated in Oaxaca, Mexico, 5,500 years ago Oaxaca – center for preservation of cultivars In 2001, transgenes from U.S. appeared in Oaxacan maize Disappeared? Transgenic maize in Oaxaca Teosinte
Food Production exceeds population, BUT High input required Today, we are producing more food per person
Population 9 billion by 2050 • Food security = the guarantee of adequate and reliable food supply to all people at all times
Green Revolution – 1940’s From 1900 to 2000, cultivated area increased 33%, while energy inputs increased 80 times! Requires: Synthetic fertilizers Chemical pesticides Irrigation Heavy equipment Negative effects: Pollution Erosion Salinization Desertification Norman Borlaug – father of Green Revolution
Resistance to pesticides Some individuals are genetically immune to a pesticide = evolution (natural selection) They survive and pass these genes to their offspring Pesticides stop being effective Evolutionary arms race / pesticide treadmill: chemists increase chemical toxicity to compete with resistant pests
Biological control Biological control (Biocontrol) = uses a pest’s natural predators to control the pest Reduces pest populations without chemicals Ladybugs kill aphids Bacillus thuringiensis (Bt) = soil bacteria that kills many pests forestencyclopedia.net Ksda.gov
Biocontrol agents may become pests themselves No one can predict the effects of an introduced species The agent may have “nontarget” effects on the environment and surrounding economies Removing a biocontrol agent is harder than halting pesticide use ecorpestcontrol.com http://fireflyforest.net/firefly/2006/07/19/cane-toads-bufo-marinus/
Integrated Pest Management (IPM) uses multiple techniques to suppress pests Biocontrol Chemicals, when necessary Habitat alteration Crop rotation and transgenic crops Mechanical pest removal
Not all insects are pests! Pollination = male plant sex cells fertilize female sex cells By wind or animals Pollinators include: Hummingbirds Bats Insects Flowers are evolutionary adaptations to attract pollinators
Genetically modified organisms (GMO or transgenic) • Genetic engineering = laboratory manipulation of genetic material • Genetically modified organisms = organisms that have been genetically engineered by … • Recombinant DNA = DNA created from multiple organisms
Genetic engineering • Benefits • Increased nutritional content • Increased agricultural efficiency • Rapid growth • Disease and pest resistance • Negatives • Risks are not yet well understood • Protests from environmental activists, small farmers, and consumer advocates
Transgenic organism = an organism that contains DNA from another species Transgenes = the genes that have moved between organisms
Crop diversity and food security • How does preserving native varieties protect food security? • How do market forces discourage diversity?
Eating animal products has significant impacts • As wealth and commerce increase, so does consumption of meat, milk, and eggs • Global meat production has increased fivefold • Per capita meat consumption has doubled
Feedlots (factory farms), also called Concentrated Animal Feeding Operations (CAFOs) • Concerns? Concerns?
Benefits of feedlots: • Greater production of food • Important in countries with high levels of meat consumption, like the U.S. • They take livestock off the land and reduces the impact that they would have on it • Drawbacks of feedlots: • Contributions to water and air pollution • Poor waste containment causes outbreaks in disease • Heavy uses of antibiotics to control disease
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 fuel energy than industrial agriculture • Organic agriculture = Uses no synthetic fertilizers, insecticides, fungicides, or herbicides • Relies on biological approaches (composting and biocontrol)
The benefits of organic farming • For farmers: • Lower input costs, enhanced income from higher-value products, reduced chemical costs and pollution • Obstacles include the risks and costs of switching to new farming methods and less market infrastructure • For consumers: • Concern about pesticide’s health risks • A desire to improve environmental quality • Obstacles include the added expense and less aesthetically appealing appearance of the product
Organic agriculture succeeds in cities • Community gardens = areas where residents can grow their own food • In Cuba, over 30,000 people work in Havana’s gardens, which cover 30% of the city’s land • Record yields for 10 crops in 1996-1997
“Locavores” = eat only locally grown food • Community-supported agriculture (CSA) = consumers pay farmers in advance for a share of their yield • Community gardens = areas where residents can grow their own food
