Week 6 Lecture 10 Energy Agriculture Environment What is Agriculture Cultivation of plants and animals for human use Remove certain species to focus nutrients light and water on other species o weed them eradicate animals etc Most of the world works as farmers Humans are an Evolutionary Force o Artificial Selection versus Natural Selection o Creates interdependence o We not only are influenced by evolution but we are also involved in influencing the factors of evolution we are affected and we effect o direct indirect ways we influence evolution Why o Aesthetic purposes flowers etc o For our livelihood o Self protection Domestication is a Gradual Unplanned Process Hunting Selective Hunting Herding Selective Breeding Genetic Modification Plant Domestication Most of the World s food is directly and indirectly provided by 14 crops o In order of importance Wheat Rice Maize Potatoes Sweet Potatoes Manioc Sugarcane Sugar Beet Common Beans Soybeans Barley Sorghum Coconuts and Bananas The Origins Diffusion of Agriculture The Neolithic Revolution Begins around 10 000 B P 8000 BC Appears in several independent locations o indigenous crops that were able to be cultivated Southwest Asia 8500 B C Wheat barley pea lentil chickpea etc Fertile Crescent Iran Iraq Independent origin China 7500 BC Millet Rice Soybean Pig Silk Worm Millet grows in drier environments Independent Origin Indus Valley 7000 BC not independent Pakistan modern day Sesame Eggplant Humped Camel Pigs Agriculture diffused from the Fertile Crescent Egypt 6000 BC not independent Fig Cat Donkey Western Europe 6000 3500 BC oats poppy rye not independent Agriculture from Fertile Crescent Egypt Meso America 3500 BC Corns Beans Squash Turkey Columbian Exchange Corn Andes Amazonia 3500 BC Potatoes Manioc Llama Guinea Pig New Guinea 7000 BC Sugarcane Banana Sahelian Africa 5000 BC Sorghum Ethiopia Coffee Teff West Africa 3000 BC African Yams Oil Pams etc Eastern North America 2500 BC Goosefoot Sunflowers Grain Legume Complexes Found in Major Centers of Domestication Legumes act as Nitrogen Fixers o Bacteria Nodules on Roots o Legumes tend to have bacteria and live in a symbiotic relationship where the waste product is nitrogen o Plants need nitrogen in order to live Serves Two Functions o 1 Maintain Soil Fertility o 2 Provide Carbohydrates Protein o In our three main sources of crops each had grain legume complexes China rice main crop soybeans legume The Fertile Crescent Wheat Carbohydrate and Peas Protein Hummus The Americas Beans Protein and Corn Carbohydrate Why did Hunter Gathering People turn to Agriculture In a Resource Rich Environment Hunting and Gathering Produces 50 kcal of NRG per 1kcal expended Agriculture Produces 17kcal of NRG per 1kcal expended What is the incentive to switch to agriculture o Population Growth best reason Demographic Hypotheses Agriculture provides more NRG per Unit of Land Hunting Technology Increasing Population Less Resources Reduced Mobility Agriculture Intensification of Land Use Agriculture is an Auto Catalytic Process Agriculture potentially reorganized society A process that re perpetuated itself Agriculture creates a hierarchy population Intensification of Agriculture Hierarchy Intensification of Agriculture Loss of Hunting Gathering Knowledge Dependency Farmland and People 2000 Location Asia Africa North America South America Europe Australia World Asia intensive more labor North America extensive use of the land The Green Revolution Not an environmental revolution Agricultural Innovations from mid 1940s to 1970s Normal Borlang 1914 2009 Led to dramatically increased Food Yields n the Developing World India Philippines Mexico etc Involved o High Yielding Varieties HYVs o Fertilizers o New Management Practices o New forms of Inputs o Mechanization of agriculture in the developing world large food increase in the developing world food production Critiques Industrialized Agriculture Fossil Fuels Worsened environmental problems Benefited Wealthy Farmers Exacerbated Wealth Gap Genetic Modification GM Crops Safety Ethics Ownership Global Consumption of Meat rising rapidly Domesticated Animals Rising o 7 2 Billion Rapid Growth in Developing Countries Should We Eat Lower on the Food Chain The Ecological Case for Vegetarianism Our Good Choices Resource Use Choices Trophic Hierarchy o About 90 of Energy is lost to cellular respiration as energy is passed up to the next Trophic Level One kg of protein requires of Land of H20 Beef 245m 2 750kg Milk 23 5 m 2 250 kg Pork 90m 2 175kg Egg 22m 2 15kg Chicken 14m 2 50 kg Environmental Impacts of Agriculture 1 Soil Erosion o Wind Water o Air Quality o Plowing soil erosion o Slash Burning soil erosion o Overgrazing Desertification can be exacerbated in Arid environments Stream Bank Trampling Dust Bowl Some Strategies to Mitigate Soil Erosion Contour Plowing Strip Cropping mixing different crops with one another o technique used to reduce soil erosion Terracing traditional technique o Not used in N America Riparian Buffers No Till Agriculture o Stems and roots are left to bold soil and help replenish fertility o No Till Increasing 7 1991 30 2001 10 05 2012 07 06 00 10 05 2012 07 06 00