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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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Methods of producing food
Key Concepts Methods of producing food Increasing food production Environmental effects of food production Increasing sustainability
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Croplands (grain – 76% world’s food)
How Is Food Produced? Sources of food Croplands (grain – 76% world’s food) Rangelands (grazing livestock – 17%) Oceanic Fisheries (fish – 7%)
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Increase in Global Food Production Since 1950 Due to:
Increased technology: tractors, farm machinery, fishing boats, etc. Inorganic chemical fertilizers Irrigation Pesticides High yield varieties of corn, rice, and wheat Densely populated feedlots and pens (cattle, pigs, chickens) Aquaculture
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But, this increase has led to:
Environmental degradation Pollution Lack of water for irrigation Overgrazing Overfishing Loss of vital ecological services
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What plants and animals feed the world?
Wheat, rice, and corn provide over half the calories we consume globally Annuals: must be replanted every year 15 plant and 8 terrestrial animal species provide over 90% of our food 2/3 of world’s population survive primarily on grains As incomes rise, people consume more meat (more grain indirectly) Beef, pork, and chicken are main animal sources of food
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Types of Food Production
Industrialized/High-put Agriculture Traditional
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Major Types of Agriculture INDUSTRIALIZED
Plantation agriculture Practiced primarily in tropical developing countries Involves growing cash crops (bananas, coffee, soybeans, sugarcane, cocoa, and vegetables) on large monoculture plantations, mostly for sale to developed countries
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Major Types of Agriculture INDUSTRIALIZED
Industrialized (high-input) Use fossil fuels, water, fertilizer, pesticides to produce large quantities of a single crop (monoculture)
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Major Types of Agriculture TRADITIONAL
44% of World’s People practice this Traditional subsistence: Uses mostly human labor Draft animals to produce only enough crops and livestock for the family’s survival
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Major Types of Agriculture TRADITIONAL
Traditional intensive Increased input of human and draft labor Increased input of water Increased input of fertilizer Enough food to feed family and make an income Attempt to increase yield to produce extra for sale
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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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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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Shifting cultivation in tropical forests in developing countries
An average of 60% of the people in developing countries are involved DIRECTLY in producing food, compared with only 8% in developed countries and 2% in the United States. Land Labor Capital Shifting cultivation in tropical forests in developing countries Land Nomadic herding in developing countries Labor Capital
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Kilocalories of fossil fuel input per kilocalorie of protein output
Food Type Kilocalories of fossil fuel input per kilocalorie of protein output Feed lot beef 20-78 Pigs 35 Broiler chicken 22 Rangeland Beef 10 Sheep 10 Vegetables 2-4
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© 2004 Brooks/Cole – Thomson Learning
Croplands Ecological Services Economic Services • Help maintain water flow and soil infiltration • Provide partial erosion protection • Can build soil organic matter • Store atmospheric carbon • Provide wildlife habitat for some species • Food crops • Fiber crops • Crop genetic resources • Jobs
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Producing Food by Green-Revolution Techniques (1950-1970)
High-input monoculture Selectively bred or genetically-engineered crops High inputs of fertilizer Extensive use of pesticides High inputs of water Increased intensity and frequency of cropping (> yield, several times/season; saves land)
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Green Revolutions First green revolution (developed countries)
Second green revolution (developing countries) Major International agricultural research centers and seed banks
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Semidwarf Rice called IR-8.
CHINA INDONESIA HIGH-YIELD HYBRID DO NOT POST TO INTERNET Semidwarf Rice called IR-8.
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Producing Food by Traditional Techniques (Interplanting)
Intercropping: 2 or more different crops are grown at the same time Polyvarietal cultivation: several varieties of the same crop are planted at the same time Agroforestry (alley cropping): crops and trees are planted together Polyculture: a complex form of intercropping in which many different plants maturing at different times are planted together
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ADVANTAGES of POLYCULTURE
Less need for fertilizer Less need for water (root systems are at different depths) Protection from wind and water erosion (soil covered year-round) Less need for insecticides (natural predators thrive) Less need for herbicides (weeds have trouble competing) Insurance in case of bad weather because of diversity of crops produced
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On average, low-input polyculture, with 4 or 5 different crop species, produces higher yields per hectare of land than high-input monoculture.
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Malnutrition: deficiency of nutrients
Undernutrition: lack of food to meet basic needs (getting fewer calories per day than needed) Malnutrition: deficiency of nutrients in diet (deficiency of protein and other key nutrients) Overnutrition: too many calories lead to overweight
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MARASMUS: “to waste away”
Occurs when a diet is both low in calories and protein Usually occurs in young children
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KWASHIORKOR: “displaced child”
Severe protein deficiency Usually occurs in children 1 – 3 years of age
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Undernutrition and Malnutrition
About 1 in 6 people in developing countries is chronically undernourished or malnourished Each year at least 10 million people, half of them children under 5, die prematurely from: Undernutrition Malnutrition Increased susceptibility to normally nonfatal diseases Infectious diseases from contaminated drinking water
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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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Micronutrient Deficiencies
The most widespread micronutrient deficiencies include Vitamin A, Iron and Iodine. Vitamin A - plays essential roles in vision, growth, and development; the development and maintenance of healthy skin, hair, and mucous membranes; immune functions; and reproduction (found in foods like sweet potato, carrot, mango, broccoli, spinach) Iron – is an essential component of hemoglobin which transports oxygen throughout the body and is important in many metabolic reactions (found in foods like chick peas, boiled spinach, dried apricots and figs) Iodine – plays an essential role in hormone development in the human body. If you don't have enough iodine in your diet, it can lead to an enlarged thyroid gland (goitre) or other iodine deficiency disorders (found in seafood, iodized salt and some vegetables)
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Overnutrition Food energy intake exceeds energy use and causes body fat (obesity) About 1 out of every 7 adults in developed countries is obese In the U.S. about 1 out of every 5 adults is obese
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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 of lakes and slow-moving rivers from 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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Crop Desired trait (color) Cross breeding Pear Apple Offspring Cross breeding Best results New offspring Desired result
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Phase 1 Make Modified Gene cell gene DNA Plasmid DNA Genetically
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
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Concerns with GMO’s “Frankenfood” We know far too little
GMO’s cannot be recalled if they cause harm No mandatory labeling (at this time) Crop seeds with “terminator genes”
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Advantages and Disadvantages of Genetically Modified Foods
Projected Advantages Projected Disadvantages Need less fertilizer Need less water More resistant to insects, plant disease, frost, and drought Faster growth Can grow in slightly salty soils Less spoilage Better flavor Less use of con- ventional pesticides Tolerate higher levels of herbicide use Irreversible and unpredictable genetic and eco- logical effects Harmful toxins in food from possible plant cell mutations New allergens in food Lower nutrition Increased evolution of pesticide- resistant insects and plant diseases Creation of herbicide- resistant weeds Harm beneficial insects Lower genetic diversity Advantages and Disadvantages of Genetically Modified Foods
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Will People Try New Foods?
Winged bean-protein rich legume Produces its own nitrogen Has multiple edible parts Microlivestock (INSECTS)-there are about 1500 edible species; 3 – 4 times as protein rich as beef, fish, or eggs Black ant larvae (Mexico) Giant waterbugs (Thailand) Emperor moth caterpillars (South Africa) Cockroaches (Kalahari desert) Butterflies (Bali) Ants (Colombia)
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Kilograms of grain needed per kilogram of body weight
Producing More Meat Kilograms of grain needed per kilogram of body weight Beef cattle 7 Pigs 4 Chicken 2.2 Fish (catfish or carp) 2 Rangeland Pasture Efficiency Adaptations of rangeland plants Range condition and management Environmental consequences
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Rangeland and Pasture Rangeland is land that is too dry, too steeply sloped, or too infertile to grow crops (makes up about 40% of ice-free land) Pasture is managed grasslands or enclosed meadows usually planted with domesticated grasses
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Ungrazed Grazed Recovery
Ecology of Rangeland Plants. Rangeland grasses grow from the bottom up and are renewable as long as the bottom half of the plant (where photosynthesis takes place) is not eaten. Ungrazed Grazed Recovery Metabolic reserve intact Metabolic reserve Metabolic reserve
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Ungrazed Overgrazed Death
If the metabolic reserve is eaten (like during overgrazing) the plant is weakened and can die. Ungrazed Overgrazed Death Metabolic reserve Most of metabolic eaten
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Rangeland: Overgrazed (left) and lightly grazed (right.)
DO NOT POST TO INTERNET
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Overgrazed Riparian Zone Recovery 10 Years Later
Arizona’s San Pedro River Recovery 10 Years Later
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Undergrazing Can reduce the net primary productivity of grassland vegetation and grass cover More likely in arid areas
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Environmental Consequences of Meat Production
More than half of world’s cropland is used to produce livestock feed Livestock consume 36% of world’s grain Livestock use more than half the water drawn from rivers and aquifers (irrigation) Manure runoff leads to water pollution Erosion resulting from grazing Cattle produce 16% of methane (greenhouse gas)
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Fishing methods (bycatch – thrown back in) Sustainable yield
Catching and Raising More Fish The World’s 3rd major food-producing system Fisheries – concentrations of particular aquatic species in a given ocean area Fishing methods (bycatch – thrown back in) Sustainable yield Overfishing (Tragedy of the Commons) Commercial extinction (over fishing) Aquaculture Fish farming and ranching
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float buoy Spotter airplane Trawler fishing Fish farming in cage
Purse-seine fishing trawl flap sonar trawl lines fish school trawl bag Fish caught by gills Drift-net fishing float buoy Long line fishing lines with hooks
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(thousands of metric tons)
800 600 400 200 1960 1970 1980 1990 2000 Year 80 70 60 50 40 30 20 (thousands of metric tons) Harvest (kilograms/tow) Abundance
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Modified Life Cycle Normal Life Cycle Human capture Fish change form
Salmon processing plant Eggs are taken from adult females and fertilized with sperm “milked” from males Modified Life Cycle To hatchery Fish change form Human capture Fish enter rivers and head for spawning areas In the fall spawning salmon deposit eggs in gravel nests and die Normal Life Cycle Fry hatch in the spring... Grow to maturity in Pacific Ocean in 1-2 years Eggs and young are cared for in the hatchery And grow in the stream for 1-2 years Grow to smolt and enter the ocean... Fingerlings are released into river Fingerlings migrate downstream
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AQUACULTURE Advantages Disadvantages Highly efficient
High yield in small volume of water Increased yields through crossbreeding and genetic engineering Can reduce overharvesting of conventional fisheries Little use of fuel Profit not tired to price of oil High profits Large inputs of land, feed, and water needed Produces large and concentrated outputs of waste Destroys mangrove forests Increased grain production needed to feed some species Fish can be killed by pesticide runoff from nearby cropland Dense populations vulnerable to disease Tanks too contaminated to use after about 5 years AQUACULTURE
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Government Agricultural Policy
Artificially low prices – consumers are happy, but farmers don’t make much money Subsidies – given to farmers to keep them in business (comes from taxpayer’s money) Elimination of price controls – let farmers respond to market demand without government interference Food aid – with any excess food
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Solutions: Sustainable Agriculture
Low-input agriculture Organic farming More benefits to the poor Increasing funding for research in sustainable techniques
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Components of More SUSTAINABLE, LOW THROUGHPUT Agriculture
Increase Decrease High-yield polyculture Organic fertilizers Biological pest control Integrated pest management Irrigation efficiency Perennial crops Crop rotation Use of more water- efficient crops Soil conservation Subsidies for more sustainable farming and fishing Soil erosion Soil salinization Aquifer depletion Overgrazing Overfishing Loss of biodiversity Loss of prime cropland Food waste Subsidies for unsustainable farming and fishing Population growth Poverty Components of More SUSTAINABLE, LOW THROUGHPUT Agriculture
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