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Food The major limiting factor to human population growth The major limiting factor to human population growth Depends on environment and socio- political.

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Presentation on theme: "Food The major limiting factor to human population growth The major limiting factor to human population growth Depends on environment and socio- political."— Presentation transcript:

1 Food The major limiting factor to human population growth The major limiting factor to human population growth Depends on environment and socio- political issues Depends on environment and socio- political issues Right now distribution is the main problem Right now distribution is the main problem If the human population continues to grow, quantity will be the problem If the human population continues to grow, quantity will be the problem

2 Where does our food come from? Land crops and livestock! Land crops and livestock! –Only 14 species of plants Cash crops Cash crops Subsistence crops Subsistence crops Top food crops: Top food crops: –Wheat, rice, maize, potatoes Earth as an Apple

3 How much food do people need? 2600 calories/day 2600 calories/day If they dont get this: undernourishment If they dont get this: undernourishment If they dont get specific nutrients: malnourishment If they dont get specific nutrients: malnourishment –Marasmus, kwashiorkor, chronic hunger On the flip side of the coin: obesity On the flip side of the coin: obesity

4 Nutrition Undernourishment = Undernourishment = too few calories too few calories (especially developing world) (especially developing world) Overnutrition = Overnutrition = too many calories too many calories (especially developed world) (especially developed world) Malnutrition = lack of nutritional requirements Malnutrition = lack of nutritional requirements (causes numerous diseases, esp. in developing world) (causes numerous diseases, esp. in developing world) Figure 9.2

5 Percentage of population affected by undernutrition by country, according to United Nations statistics

6 Global food security The world still has 800 million hungry people, largely due to inadequate distribution. The world still has 800 million hungry people, largely due to inadequate distribution. Global food security is a goal of scientists and policymakers worldwide. Global food security is a goal of scientists and policymakers worldwide.

7 HOW TO FEED THE WORLD om/watch?v=QloMOO G-bbE om/watch?v=QloMOO G-bbE om/watch?v=QloMOO G-bbE om/watch?v=QloMOO G-bbE

8 The best ways Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime. – Lao Tzu Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime. – Lao Tzu Create systems where food is grown and distributed locally Create systems where food is grown and distributed locally

9 Agriculture

10 2,000 1,500 1, Grain production (millions of tons) Total World Grain Production Year

11 Per capita grain production (kilograms per person) World Grain Production per Capita 200 Year

12 Calories per day per person 3,700 3,500 3,300 3,100 2,900 2,700 2,500 2,300 2, Year Developed countries World Developing countries

13 Figure 14-3 Page 276 Croplands 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 Ecological ServicesEconomic Services Food crops Fiber crops Crop genetic resources Jobs Natural Capital 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

14 Biodiversity Loss 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 Soil Erosion Loss of fertility Salinization Waterlogging Desertification

15 Air Pollution Greenhouse gas emissions from fossil Fuel issue Other air pollutants from fossil fuel use Pollution from pesticide sprays Water Water waste 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

16 4%2%6%5% 17% of total commercial energy use CropsLivestockFood processingFood distribution and preparation Food production

17 Producing and eating meat Land use issues Land use issues –More land needed More land needed for grazing than grain production More land needed for grazing than grain production Acre of grain for human consumption feeds more than an acre used for grazing Acre of grain for human consumption feeds more than an acre used for grazing Land needed to grow forage AND raise animals: Housing, food storage and waste disposal Land needed to grow forage AND raise animals: Housing, food storage and waste disposal

18 Producing and eating meat Energy issues Energy issues –Eating at a lower trophic level More solar energy available to humans, less lost through trophic transfer More solar energy available to humans, less lost through trophic transfer –Storage of grain less energetically expensive than processing and storing meat Transport, slaughter and refrigeration Transport, slaughter and refrigeration –Energy costs associated with meat production Producing grain for livestock Producing grain for livestock –Fertilizers, irrigation, pesticides, farm machinery Animal waste management Animal waste management –Pumping, treatment, transport, disposal Animal care and round up of free range livestock Animal care and round up of free range livestock

19 Eating less meat: Pro and Con Advantages Advantages –Reduced risk of disease Cholesterol Cholesterol –Clogged arteries –Hypertension –Heart disease –Reduced chemical exposure Hormones Hormones Steroids Steroids Antibiotics Antibiotics Pesticides (Biomag!) Pesticides (Biomag!) –Reduced exposure to disease Mad Cow Mad Cow Salmonella/ E. coli Salmonella/ E. coli Parasites Parasites Disadvantages Disadvantages –Meat an excellent source of protein Essential amino acids –Rice and Beans! Difficult to get enough protein without meat –Nutritional deficiencies Kwashikor: Protein Blindness: Vit. A Pollegra: Vit. B Anemia: Iron Inadequate essential fats balance

20 How do we address world hunger? Policy and behavioral changes Policy and behavioral changes Eat lower on the food chain? Eat lower on the food chain? Modify food distribution Modify food distribution Improve infrastructure Improve infrastructure Economic policies Economic policies –End subsidies

21 To feed the world…. Conservation of matter Conservation of matter –Available resources limit agricultural production –Nutrients used by plants Nitrates: Protein and DNA Nitrates: Protein and DNA Phosphates: DNA, RNA, ATP Phosphates: DNA, RNA, ATP –Soil degraded as nutrients removed by harvest Conservation of Energy Conservation of Energy –Trophic level energy loss Vegetarian vs Carnivorous diets Vegetarian vs Carnivorous diets Green revolution Green revolution –Increase yield per acre –Monoculture –Intensive tillage = soil erosion –Requires Energy: Emissions and oil Energy: Emissions and oil Fertilizers and pesticides: Toxic pollution, soil salinization Fertilizers and pesticides: Toxic pollution, soil salinization Irrigation: Water rights and usage Irrigation: Water rights and usage


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