3Challenges for 21st Century Reduce global hunger (food security)Meet world food demand withsustainable agricultural practicesFood safety
4OVERVIEW Feeding the world This chapter will discuss food production, maintenance of soil productivity, and the challenges of feeding the world.Various alternative methods of planting and harvesting crops, controlling pests, and raising livestock are examined.
5Warm-upImagine you are the owner of this farmland in rural Pennsylvania.What might their daily life involve?What concerns and needs would they have in order to maintain their income and way of life?Today less than 10% of agricultural land in the United States is owned and operated by families. Work with your partner and brainstorm possible reasons for this situation
6Objectives Identify the major causes of malnutrition Compare the environmental costs of producing different types of food.Explain how food distribution problems and drought can lead to famineExplain the importance of green revolution
7Humans and NutritionFood serves as a source of energy and also serves as a source materials for building and maintaining body tissues.Major nutrients in Human FoodsNutrientCompositionSourcesEnergy YieldFunctionCarbohydratesSugarsWheat, corn, and rice4 cal/gIs the main source of the body’s energyLipids (oil and fats)Fatty acids and fatty alcoholOlives, nuts, and animal fats9 Cal/gHelps from membranes and hormonesProteinsAmino acidsAnimal food and smaller amounts from plantsAbout 4 Cal/gHelps build and maintain all body structures
9Malnutrition Things to ponder Hypothesize why everyone does not get enough foodMalnutrition is a condition that occurs when people do not consume enough Calories or do not eat a sufficient variety of foods to fulfill all of the body’s needs.In some parts of the world, the only sources of food may be corn or rice. Each of these food contains proteins but lacks one of the essential amino acids.
10Food choices if for the same amount of money, you could buy three loaves of bread or this one hamburger patty, which would choose and why?Hamburger pattyWhole grain bread
11Refer to the graph in page number 380 in your text book and answer the following Discuss with your partner and be prepared to answer Why do you think proteins and fats form a larger percentage of the diets of western, developed countries, and less in developing countries? In the United States, almost half of all Calories people consume come from meat, fish, and oil. Japanese diet traditionally included rice, vegetables, and seafood, have started to consume beef in recent decades.
12A healthy dietA healthy diet is one that maintains a balance of the right amounts of nutrients, minerals, and vitamins.In most parts of the world, people east large amounts of food that is high in carbohydrates, such as rice, potatoes and bread.The food produced in the greatest amounts all over the world are grains, whose seeds are rich in carbohydrates. Besides eating grains, most people east fruits, vegetables, and smaller amounts of nuts, meats, and other food rich in fat and proteins.
13Food efficiencyThe efficiency of a given type of agriculture is a measure of the quantity of food produced on a given area of land with limited inputs of energy and resources.An ideal food crop is one that efficiently produces a large amount of food with little negative impact on the environment.A given area of land can usually produce more food for humans when it is used to grow plants than when it is used to raise animals. Can you give reasons?Meat from animals generally provides more nutrients pr gram than most food from plants.
14Math PracticeExtra calories An active man who weighs 70 kg maintains his weight if he eats 2,700 Cal per day. Unused calories are converted into stored fat at the rate of 1 kg of fat per 9,000 Cal that are unused. If this active man consumes 3,600 cal per day, how much weight does he gain each year?
15Solution 3,000 Cal/day – 2,700 Cal/day = 900 Cal/day 900 Cal/day x 365 days/year = 328,500 Cal/year328,500 Cal/year÷ 9,000 = 36.5 kg weight gained /year(1 kg of fat per 9,000 Cal)
16Old and New FoodsResearchers hope to improve the efficiency of food production by studying plants and other organisms that have high yield – the amount of food that can be produced in a given area.Researchers are interested in organisms that can thrive in various climates and that do not require large amounts of fertilizer, pesticides, or fresh water.The Next Diet for a small planet, by Lappe and her daughter (try to get this book and read.
17Thoughts for your mindI would like you to consider the potential global effects if a greater proportion of people ate plant-and grain based diets as advocated by Lappe.
18Staple food around the world Asia – riceParts of China and India – wheatCentral America –cornmealEuropean Countries –potatoes and bread grains such as wheat and ryeEthiopia – millet and buckwheat – made into a fermented bread called injera
19World Food Problems: some people become malnourished because they do not get enough food.Malnourished children in Bangladesh wait for food assistance.It is mainly theResult of poverty.
20World Food ProblemsUnequal Distribution: Food is not equally divided equally. Even in the United States, many poor people suffer from malnutrition.Wars and political strife can also lead to malnutrition, because interrupt transportation system.During wars, even if the food is available, it often cannot be transported to the people who need it.
21Droughts and FaminesA drought is a prolonged period during which rainfall is below average. Crops produced without irrigation may produce low yields or fail entirely.If drought occurs, there may be no seed to plant the following year. People in a given area can usually survive one crop failure. After a long drought the soil may be less able to support the production of food crops
22World grain production Worldwide grain production has increased steadily, but not as rapidly as the population has grown.
23The Green RevolutionBetween 1950 and 1970, Mexico increased the production of wheat eight fold and India doubled its production of rice.Worldwide increase in crop yield resulted from the use of new crop varieties and the application of modern agricultural techniques. These changes were called the green revolution
24Negative effects of Green Revolution Most new varieties of grain produce large yields only if they receive large amounts of water, fertilizer, and pesticides.Machinery, irrigation, and chemicals required by new crop varieties can degrade the soil if they are not used properly.Overuse of fertilizers and pesticides can result in lower yield of crops.Green revolution had negative impact on subsistence farmers. Before the green revolution, subsistence farmers worked most of the world’s farmland. But they could not afford the equipment, water, and chemicals needed to grow the new crop varieties.
25Answer all questions Identify the major causes of malnutrition Explain how drought and the problems of food distribution can lead to famines.Describe the importance and effects of the green revolutionWhat do crops of green revolution need in order to produce high yields?