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Chapter 12

Chapter 12. Food Resources. Nutritional Deficiencies. Undernutrition: less than 90% of minimum calories(serious if under 80%) Malnutrition: deficient in protein + nutrients Marasmus: low calories and protein (age 0-1) Kwashiorkor: very low protein (age 1-3). Macronutrient Deficiencies.

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Chapter 12

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  1. Chapter 12 Food Resources

  2. Nutritional Deficiencies • Undernutrition: less than 90% of minimum calories(serious if under 80%) • Malnutrition: deficient in protein + nutrients • Marasmus: low calories and protein (age 0-1) • Kwashiorkor: very low protein (age 1-3)

  3. Macronutrient Deficiencies Vitamin A (carrots) • affects 124 million children:blindness, reduces resistance to diarrhea • gene splicing: beta carotene rich variety Iron (spinach) needed for hemoglobin--> anemia Iodine (seafood) deficiency leads to goiter, enlargement of thyroid

  4. Key Nutrients for a Healthy Human Life

  5. 12-2 How Is Food Produced? • Concept 12-2A We have sharply increased crop production using a mix of industrialized and traditional agriculture. • Concept 12-2B We have used industrialized and traditional methods to greatly increase supplies of meat, fish, and shellfish.

  6. Food Production Has Increased Dramatically • Three systems produce most of our food • Croplands: 77% • Rangelands, pastures, and feedlots: 16% • Aquaculture: 7% • Importance of wheat, rice, and corn • Tremendous increase in global food production

  7. Improvements since 1950 Improved machinery Inorganic fertilizer Irrigation Pesticides High yield varieties of rice, corn, and wheat Changes in Food Supply Systems Croplands

  8. Croplands Problems Environmental degradation Pollution Water shortage Changes in Food Supply System

  9. Rangelands Problems Overgrazing Changes in Food Supply System

  10. Fisheries Improvements High tech fishing boats (radar, nets) Aquaculture ponds Problems - Overfishing Changes in Food Supply System

  11. Main Foods • Rice, corn, and wheat (traditional grains) provide more than 50% of world’s calories • 2/3 of world population depends on traditional grains • Affluence leads to use of grain to feed animals (90% energy loss) • Fish and shellfish provide only 1% of energy in world’s diet

  12. Major Types of Food Production • Crop growth replaces late-successional community with early-successional community (usually monoculture)

  13. Major Types of Food Production • Industrialized (high-input) agriculture • 25% of all cropland • plantation agriculture (cash crops) • Tradition subsistence • use humans and draft animals to feed family • Shifting agriculture, nomadic livestock herding Traditional intensive agriculture increased input:labor, water, fertilizer

  14. Agriculture and Environmental Problems • Soil erosion • Desertification • Salinization and waterlogging • Water shortages • Loss of wild species • Global warming

  15. Improving Yields • Crossbreeding • Genetic engineering (insert desirable gene) • 2/3 of food products sold, not labeled • New foods • Winged bean, insects (58-78% protein) • Increased irrigation (declining supply) • 40% of all crops come from irrigated land • Use more land (irrigation, bio. loss, urban)

  16. Science Focus: Soil Is the Base of Life on Land • Soil composition • Soil formation • Layers (horizons) of mature soils • O horizon: leaf litter • A horizon: topsoil • B horizon: subsoil • C horizon: parent material, often bedrock • Soil erosion

  17. Soil Formation and Generalized Soil Profile

  18. Green Revolution • Developed countries, 1950-1970 • 3 steps 1. Use high yield crops 2. Use large amounts of fertilizer, pesticides, and water 3. Increase frequency of planting

  19. 2nd green revolution • Dwarf varieties for tropics • Fast growth • High input:water, chemicals, oil • Conserves forest, grassland, etc

  20. Agribusiness in U.S. 1. 650,000 farmers (2% of population) a) 9% of population is part of ag system, from growing to market 2. Biggest industry in US (18% of GNP) • US 10-12% income on food vs 40-70% dev • Overall: 1 unit food energy = 10 units fossil fuel

  21. Crossbreeding and Genetic Engineering Can Produce New Crop Varieties (1) • Gene Revolution • Cross-breeding throughartificial selection • Slow process • Genetic engineering • Genetic modified organisms (GMOs): transgenic organisms

  22. Meat Production and Consumption Have Grown Steadily • Animals for meat raised in • Pastures • Feedlots • Meat production increased fourfold between 1961 and 2007 • Demand is expected to go higher

  23. Industrialized Meat Production

  24. Fish and Shellfish Production Have Increased Dramatically • Aquaculture, blue revolution • World’s fastest-growing type of food production • Dominated by operations that raise herbivorous species • Polyaquaculture

  25. 140 120 100 80 Wild catch Catch (millions of metric tons) 60 40 20 Aquaculture 0 1950 1960 1970 1980 1990 2000 2010 Year Total World Fish Catch Fig. 12-8a, p. 285

  26. Change in Food Production • Good • b/w 1950 and 1990, food prod tripled and per capita food prod up by 36% • World Bank: food price in 2000 was 1/3 food price in 1957 (taking inflation into account) Bad -in Africa and former USSR per capita food prod down -since 1985, global grain prod level, per capita down lower price?, limits on high input crops? --> erosion, etc

  27. Food Distribution Problems • Poverty • 80% of all malnourished children live in countries with enough food to feed them • Political corruption • Inadequate storage facilities

  28. Rangeland and Pastures • Rangeland (40% managed by BLM) • Pasture (managed or enclosed) • Overgrazing (metabolic reserve) • Compaction • Nomadic herding • Riparian zones • Feedlots

  29. Fish • Main fishing countries: Japan, Fmr Soviet Union, Peru, Chile, China, U.S. • 65% of commercial catch comes from ocean • 25% from aquaculture • 10% from inland freshwater

  30. Nets • Trawlers drag net along bottom disrupting habitats • Purse-seine nets: drawstring closes net around surface fish, e.g. tuna • Longline nets: 80 miles with thousands of hooks

  31. Drift Nets • Formerly, 34 miles long, hang 50 ft deep • Nearly invisible, catch and kill everything that comes in contact, famously, dolphins • UN outlawed drift nets longer than 1.6 mi in 1993. Ban is not well enforced

  32. Sustainability • Sustainable yield is hard to establish • Overfishing may lead to commercial extinction, e.g.orange roughy • 11 of 15 most important fisheries are overfished (cod off Cape Cod, salmon in Washington and Oregon) • Over 100 international fishery disputes • Global warming: degrade coral reef • Ozone depletion: increased UV penetration

  33. Aquaculture • Fish and shellfish • China produces 62% of output • Fish farming: raising fish under controlled conditions • Fish ranching: hold, release anadromous fish, catch when they return to spawn • Developing: herbivores • Developed: stock lakes, shellfish, trout, salmon • 65% of freshwater fish • Production could double in next 10 years

  34. Aquaculture • China has developed fish polyculture • 4 species of carp feed at different trophic levels • Aquaculture produces • 90% oysters, 40% salmon, 50% shrimp, prawn • 65% of freshwater fish worldwide • Catfish is leading US aquaculture product • Pros:little space, saves conv fisheries • Cons:large output of waste, disease spreads • Mangroves are cleared to raise shrimp (Indonesia)

  35. Key Concepts • Types and characteristics of pesticides • Pros and cons of using pesticides • Pesticide regulation in the US • Alternatives to chemical pesticides

  36. Pests • Compete with humans for food • Invade lawns and gardens • Destroy wood in houses • Spread disease • Are a nuisance • May be controlled by natural enemies

  37. Pesticides: Types • Chemicals that kill undesirable organisms • Insecticides • Herbicides See Table 23-1 p. 520 • Fungicides • Rodenticides

  38. First Generation Pesticides • Primarily natural substances • Sulfur, lead, arsenic, mercury • Plant extracts: nicotine, pyrethrum (from head of chrysanthemum), and rotenone (from roots of rainforest legumes)

  39. Second Generation Pesticides • Primarily synthetic organic compounds • Broad-spectrum agents • Narrow-spectrum agents • Persistence in the environment See Table 23-1 p. 520

  40. The Case for Pesticides • Save human lives • Increase food supplies and lower costs • Work better and faster than alternatives • Health risks may be insignificant compared to benefits • Newer pesticides are becoming safer • New pesticides are used at lower rates

  41. Characteristics of an Ideal Pesticide • Affects only target pests • Harms no other species • No genetic resistance • Breaks down quickly in the environment • More cost-effective than doing nothing

  42. The Case Against Pesticides • Genetic resistance • The pesticide treadmill • Can kill non-target and natural control species • Can cause an increase in other pest species • Pesticides do not stay put • Can harm wildlife • Potential human health threats

  43. Pesticide Regulation in the United States • Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) • EPA Evaluation of chemicals • Tolerance levels • Inadequate and poorly enforced • Food Quality Protection Act (FQPA)

  44. Other Ways to Control Pests • Economic threshold • Adjusting cultivation practices • Use genetically-resistant plants • Biological pest control • Insect birth control • Hormones and pheromones • Hot water • Ionizing radiation

  45. Integrated Pest Management • Ecological system approach • Reduce pest populations to economic threshold • Field monitoring of pest populations • Use of biological agents • Chemical pesticides are last resort

  46. Why is Integrated Pest Management not More Widely Used? • Requires expert knowledge • Slower than conventional pesticides • Initial costs may be high • Hindered by government subsidies

  47. Original pest population Introduction biological control Economic threshold Pest density Equilibrium position Equilibrium position Reduced pest population Time Effects of IPM Fig. 20.7, p. 507

  48. Government Assistance • Keep food prices low • Good for consumers, bad for farmers • Give farmers subsidies • $100 billion in US , keeps prices low but may inhibit production in developing countries • Eliminate price controls and subsidies • If prices rise too high, hurts poor Subsidies for good behavior?

  49. Interplanting(more than one crop on same plot) 1) Polyvarietal cultivation -One plot, varieties of same crop 2) Intercropping one plot, 2 or more different crops 3) Alley cropping Crops and trees together 4) Polyculture Different crops with different yield times, different root depths

  50. Soil Degradation 1. erosion a) water and wind b) sheet, rill, gully c) worldwide impact (Madagascar, Haiti) 2. desertification a) 10-50% loss of productivity b) due to: overgrazing, deforestation, surface mining, improper irrigation, salinization, waterlogged soil, farming on unsuitable land, soil compaction

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