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Living in the Environment
Food Resources G. Tyler Miller’s Living in the Environment 13th Edition Chapter 13
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Key Concepts Methods of producing food Increasing food production
Environmental effects of food production Increasing sustainability
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How Is Food Produced? Sources of food Primary plants Primary animals
cropland (76%) rangeland (17%) ocean fisheries (7%) Primary plants wheat, corn, rice Primary animals beef, pork, chicken
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Major Types of Agriculture
Traditional Agriculture Traditional subsistence uses human labor and draft animals produce only enough food for a family’s survival. Traditional intensive increased human and draft labor, fertilizer, and water higher yields producing enough food for their family and to sell for income.
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Major Types of Agriculture
Industrialized (high input) uses large quantities of fossil fuel energy, water, commercial fertilizer, and pesticides produces huge quantities of single crops or livestock (monoculture) Plantation growing cash crops on large monoculture plantations Mostly for sale in developed countries.
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Industrialized agriculture in developed countries
Land Labor Capital Fossil fuel energy Industrialized agriculture in developed countries Land Labor Capital Fossil fuel energy Intensive traditional agriculture in developing countries
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World Food Production Plantation agriculture
Industrialized agriculture Shifting cultivation Plantation agriculture Nomadic herding Intensive traditional agriculture No agriculture
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Challenge to Farmers: Produce More Food!
Farm more land Produce higher yields per unit area
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Green Revolution Refers to dramatically increased agricultural productivity resulting from the introduction of new, high-yielding strains of grain (Golden Rice!) (rice, wheat, and maize) Ongoing since 1950s
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Producing Food by Green-Revolution Techniques
High-input monoculture Scientifically bred or genetically-engineered crops High inputs of fertilizer Extensive use of pesticides High inputs of water Increased intensity and frequency of cropping (multiple cropping)
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Green Revolutions First green revolution (developed countries)
Second green revolution (developing countries) Major International agricultural research centers and seed banks 1967-today
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Producing Food by Traditional Techniques (Low input agrodiversity)
Interplanting - simultaneously growing a variety of crops on the same plot Polyvarietal cultivation Planting several varieties of the same crop in a plot Intercropping Two or more different crops are grown at the same time on a plot
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Producing Food by Traditional Techniques (Low input agrodiversity)
Agroforestry (alley cropping) Crops and trees are planted together Polyculture Different plants maturing at various times are planted together Less fertilizer Protection from wind and water erosion Little or no insecticides Insurance against bad weather
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Food Production – good news
Production is increasing!! Total World Grain Production 2,000 1,500 1,000 500 Grain production (millions of tons) 1950 1960 1970 1980 1990 2000 2010 Year
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Food Production – bad news
Population growth has increased! World Grain Production per Capita 400 350 300 250 150 Per capita grain production (kilograms per person) 1950 1960 1970 1980 1990 2000 2010 200 Year
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Human Nutrition Macronutrients Micronutrients
Protein, carbohydrates, and fats Micronutrients Vitamins A, C, and E Minerals (iron, iodine, and calcium) Undernutrition – consuming insufficient food to meet one’s minimum daily energy needs.
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Nutrition Malnutrition – faulty nutrition, caused by a diet that does not have enough protein, essential fats, vitamins, minerals and other nutrients needed for good health. Marasmus Diet low in both calories and protein Kwashiorkor Severe protein deficiency
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Marasmus – “wasting disease”
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Kwashiorkor “displaced child”
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Feedback loop Poverty Malnutrition Decreased resistance to disease
High death rate for children energy ability to learn to work Shortened life expectancy Feedback loop
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Environmental Effects of Food Production
Biodiversity loss Soil Air pollution Water Human health
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Biodiversity Loss Soil
Loss and degradation of habitat from clearing grasslands and forests and draining wetland Fish kills from pesticide runoff Killing of wild predators to protect livestock Loss of genetic diversity from replacing thousands of wild crop strains with a few monoculture strains Erosion Loss of fertility Salinization Waterlogging Desertification
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Greenhouse gas emissions from fossil fuel issue
Air Pollution Water Greenhouse gas emissions from fossil fuel issue Other air pollutants from fossil fuel use Pollution from pesticide sprays Aquifer depletion Increased runoff and flooding from land cleared to grow crops Sediment pollution from erosion Fish kills from pesticide runoff Surface and groundwater pollution from pesticides and fertilizers Overfertilization due to runoff of nitrates and phosphates from fertilizers, livestock wastes, and food processing wastes
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Human Health Nitrates in drinking water
Pesticide residues in drinking water, food, and air Contamination of drinking and swimming water with disease organisms from livestock wastes Bacterial contamination of meat
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Increasing World Crop Production
Crossbreeding and artificial selection Genetic engineering (gene splicing) Genetically modified organisms (GMOs) Continued Green Revolution techniques Introducing new foods Working more land
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Can combine traits only from closely related species
Crop Cross breeding Desired trait (color) Apple Pear Offspring Cross breeding Best results New offspring Desired result Traditional Crossbreeding Slow process Can combine traits only from closely related species
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Phase 1 Make Modified Gene
cell Identify and extract gene with desired trait gene DNA Identify and remove portion of DNA with desired trait Plasmid Remove plasmid from DNA of E. coli E. coli DNA Insert extracted DNA (step 2) into plasmid (step3) Genetically modified plasmid plasmid Insert modified plasmid into E. coli Grow in tissue culture to make copies
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Phase 2 Make Transgenic Cell
Transfer plasmid copies to a carrier agrobacterium A. tumefaciens (agrobacterium) Agrobacterium inserts foreign DNA into plant cell to yield transgenic cell Plant cell Nucleus Host DNA Foreign DNA Transfer plasmid to surface microscopic metal particle Use gene gun to inject DNA into plant cell
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Grow Genetically Engineered Plant
Phase 3 Grow Genetically Engineered Plant Transgenic cell from Phase 2 Cell division of transgenic cells Culture cells to form plantlets Transgenic plants with new traits Half the time as conventional crossbreeding Cuts costs Allows insertion of genes from almost any other organism
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Increasing World Crop Production
Without fertilizer, water, and pesticides green revolution varieties are no more productive than traditional varieties Green revolution varieties and their needed inputs cost too much for subsistence farming. Grain yields are increasing at a much slower pace.
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Increasing World Crop Production
Actual gains from green and gene revolutions may be overstated. Crop yield may start dropping for a number of environmental reasons. Increased loss of biodiversity can limit genetic raw material.
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Increasing World Crop Production
Introducing new foods Getting farmers to take risk of growing new types of food. Getting consumers to try new foods.
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Increasing World Crop Production
Not usable Arid land 6% Tropical forest 8% Cultivated 10% Grazed 11% Forests, arid lands 14% 51% Ice, snow, deserts mountains Working more land “Many analysts believe that significant expansion of cropland is unlikely over the next few decades.”
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How about producing more meat…?
Rangeland is land that is… too dry too steeply sloped too infertile …to grow crops (40% of ice-free land area) Pastures managed grasslands or enclosed meadows
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Kilograms of grain needed per kilogram of body weight
How is meat produced? Open grazing 80% of cattle, sheep and goats are raised on rangeland Feedlots Account for 40% of the world’s meat production Kilograms of grain needed per kilogram of body weight Beef cattle 7 Pigs 4 Chicken 2.2 Fish (catfish or carp) 2
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Producing more meat Condition of the world’s rangelands
DECLINING! Environmental consequences of meat production See Connections page 299 Read Spotlight page 300
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Catching and Raising More Fish
Fisheries – concentrations of aquatic species suitable for commercial harvesting in a given body of water 55% of annual commercial catch comes from the ocean. 33% from aquaculture. 12 % from inland freshwater fishing.
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Commercial Fishing Methods
Spotter airplane Fish farming in cage Trawler fishing Purse-seine trawl flap trawl bag Long line fishing lines with hooks Drift-net fishing Fish caught by gills buoy fish school sonar trawl lines float
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Potential to harvest more fish
Fish catch increased 5-fold Per capita seafood catch doubled Since 1982 Little increase in commercial fish catch Per capita commercial fish catch falling
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Potential to harvest more fish
The primary cause of depletion of fish stocks is too many fishing boats pursuing too few fish or OVERFISHING (Tragedy of the Commons) Habitat destruction Global warming
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Aquaculture Fish farming Cultivating fish in a controlled environment.
Harvesting them when they reach the desired size. Catfish are the leading aquaculture product in the US
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Aquaculture Problems Raises demand for ocean fish as fish meal to feed aquaculture species Creating vast amounts of animal waste in coastal areas Farming of carnivorous fish increases over-fishing of smaller marine species.
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Government Agricultural Policy
Financially risky business Forms of assistance. Keep food prices artificially low. Give farmers subsides (money) to keep them in business and encourage them to increase food production. Eliminate price controls and subsides and let farmers and fishers respond to market demand without government control. Increase aid for the poor
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Future limitations to increased food production
Lack of water for irrigation Reduced genetic diversity Leveling off of yields Environmental effects which degrade existing cropland
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Solutions: Sustainable Agriculture
Slowing population growth Reducing poverty Phasing in systems of sustainable agriculture (also called organic farming)
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‘Organic’ foods Plants
Produced without synthetic pesticides, fungicides, and herbicides Cannot include genetically engineered foods or be irradiated Cannot be grown on soils fertilized with sewage sludge Animals Produced from 100% organically grown feed. Given access to outdoor range or pasture Produced without use of hormones and antibiotics
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Principles of Sustainability
Most ecosystems use renewable solar energy as the primary source of energy. Ecosystems replenish nutrients and dispose of wastes by recycling chemicals.
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Principles of Sustainability
Biodiversity helps maintain the sustainability of ecological functioning of ecosystems and serves as a source of adaptation to changing environmental conditions. In nature there are always limits to population growth and resource consumption.
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