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Ch. 9 Food. Feeding the People of the World. What do people eat?. Carbohydrates Carbs are used for a fast source of energy Examples – bread, cereal, beans potatoes Proteins building and maintaining the body Ex – meat, fish, eggs, peanuts. Lipids building and maintaining cell membranes
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Ch. 9 Food Feeding the People of the World
What do people eat? • Carbohydrates • Carbs are used for a fast source of energy • Examples – bread, cereal, beans potatoes • Proteins • building and maintaining the body • Ex – meat, fish, eggs, peanuts • Lipids • building and maintaining cell membranes • used to make some hormones • can be used as a source of energy • Ex – lard, butter, oil
Metabolism is… • -the way a person breaks down & uses energy in the body to maintain it • -it is the collection of all the chemical reactions that go on inside your body & cells
Malnutrition is… • -when a person doesn’t get enough of the right kind of nutrients
Why do some people go hungry? • Not enough food (#1reason) • the world’s population is growing faster than we can grow food • Food is not divided • throughout the world some places are not adequate to grow crops • wealthy people tend to have the food and control it • Transportation • can’t get the food to the people in very remote locations • where food is needed isn’t located where food is grown • Droughts • can cause crop yields to be poor • can cause famines – food shortage that kills many
The Green Revolution • What was it? • an effort in 1950-1970’s to increase crop yields • included introducing new grains, new farming techniques and new machinery • What did it allow for? • it allowed for greater crop yields to feed more people • What were some problems? • irrigation, pesticide & fertilizers were needed for the new crops • more crops were being produced in excess so there was a need for more manpower or machinery
What is a subsistence farmer? • farmers that grow only enough to feed and provide for their families • the green revolution really pushed the subsistent farmer out of business because they could not afford new equipment & chemicals
II. Agriculture and Soil • What is arable land? • fertile land that can be plowed for crops • Why is there less arable land today than years ago? • farmland is being used for houses, mines, roads, factories and power plants • A shortage in arable land threatens... • our ability to feed the world’s population
Farming is soil • Soil is...a mixture of minerals, organic matter, water and air • SOIL LINKS THE LVING TO THE NON LIVING • Minerals in soil • Sand Silt Clay
Erosion • Erosion is the wearing away of topsoil by wind and water • Ex: driving farm equipment over fields • What is desertification? • Is a situation in which soil fertility has been degraded so much that it becomes desert like
Soil Conservation • Conservation tillage AKA – no till • Leaves crop residue on the surface and new seeds are planted among these roots • Conserves moisture • Improves root development • Provides food & cover for wildlife • Less work because the land is worked less
Agriculture • Salinization-accumulation of salts in soil • caused by irrigation • Can reduce this by lining irrigation canals to prevent the rice of the water table • Plant salt resistant plant • Old and New Foods • Rediscover ancient plants, hope to find better adapted plants to produce high yields • Ex: amaranth (Aztecs) can survive with little water and produces grain like fruit rich in protein C. Johannesson
III. Pest Control • What is a pest? • A pest is any organism that is in a place where you don’t want it • EX: mice, flies, weeds • What is a pesticide? • A pesticide is a chemical that kills pests • Ex: DDT Organic farmers will plant a different crop each year to reduce pest naturally
Drawbacks of pesticides • Health concerns • Some pesticides can cause people to get sick • Pollution • Many pesticides are persistent and don’t break down in nature • Most persistent pesticides are banned in the USA • Resistance • is the ability of an organism to tolerate a pesticide usually b/c of genetics • If used too much a pest can build up and pass resistance (genes) onto offspring
Biological Pest Control (BPC) • BPC is pest control that uses living organisms or naturally produced chemicals to get rid of pests • Predators and pathogens • BPC where a pest is released to control pests • EX: Bt bacteria & caterpillars, ladybugs • Plant defenses • Cross breeding crops with plants that produce their own material toxins or tough leaves • Chemicals from plants • Plant plants that release natural toxins or odors near crops • Disrupting insect breeding • Spray natural chemical like pheromones or x-rays that disrupt the breeding cycles of the pest