ENV Ch 10

• Corn (maize) originated in Oaxaca, Mexico, 5,500 years ago
• In 2001, genes from genetically modified corn appeared in Oaxacan maize
• These transgenes (genes from one species used toenhance another) came from U.S. corn shipments
• Could “contaminate” native crops
• The genes did not appear in subsequent tests



• the guarantee of adequate and reliable food supply to all people at all times
• (we've reduced hunger by half since 1970, but 850 million people are still so hungrayy)

• people receive less than 90% of their daily caloric needs
• (31 million Americans are food insecure)

• receiving too many calories
• In the U.S., 25% of adults are obese
• Worldwide, more than 300 million people are obese

• a shortage of nutrients the body needs
• The diet lacks adequate vitamins and minerals

• diets lacking protein or essential amino acids
• Occurs when children stop breast-feeding
• Bloated stomach, mental and physical disabilities

• protein deficiency and insufficient calories
• Wasting or shriveling of the body

• •From 1900 to 2000, cultivated area increased
• 33%, while energy inputs increased
• 80 times!

• •Positive effects on natural resources
• Prevented some deforestation
• Preserved biodiversity

• •Negative effects on natural resources
• Pollution
• Erosion
• Salinization
• Desertification

• a large expanse of a single crop
• More efficient, increases output
• Devastates biodiversity
• Susceptible to disease and pests

chemists increase chemical toxicity to compete with resistant pests

• uses a pest’s natural predators to control the pest
• Reduces pest populations without chemicals
• Cactus moths control prickly pear

soil bacteria that kills many pests

male plant sex cells fertilize female sex cells

• •Honeybees pollinate more than 100 crops – 1/3 of the U.S. diet.
• In 2006, hives died off
• •To conserve bees:
• Reduce or eliminate pesticide use
• Plant flowering plants

laboratory manipulation of genetic material

= DNA created from multiple organisms

• •Benefits of genetic engineering:
• Increased nutritional content
• Increased agricultural efficiency
• Rapid growth
• Disease and pest resistance
• •Negatives of genetic engineering:
• Risks are not yet defined or well understood
• Protests from environmental activists, small farmers, and
• consumer advocates

the material application of biological science to create products derived from organisms

an organism that contains DNA from another species

Transgenes -the genes that have moved between organisms

• -Dangerous to human health
• -Escaping transgenes could pollute ecosystems and damage nontarget organisms
• -Pests could evolve resistance
• -Could ruin the integrity of native ancestral races
• -Interbreed with closely related wild plants

• Huge warehouses or pens designed to deliver energy-rich food to animals living at extremely high densities
• Over ½ of the world’s pork and poultry come from feedlots

• raising aquatic organisms for food in a controlled environment
• Aquatic species are raised in open-water pens or land-based ponds

• -Benefits:
• A reliable protein source
• Sustainable
• Reduces fishing pressure on overharvested wild fish stocks
• Energy efficient

• -Drawbacks
• Diseases can occur, requiring expensive antibiotics
• Reduces food security
• Large amounts of waste
• Farmed fish may escape and introduce disease into the wild

does not deplete soil, pollute water, or decrease genetic diversity

uses smaller amounts of pesticide, fertilizers, growth hormones, water, and fossil fuel energy than industrial agriculture

• Uses no synthetic fertilizers, insecticides, fungicides, or herbicides
• Relies on biological approaches (composting and biocontrol)