Chapter 15 Food and Agriculture Outline

Transcription

1 1 I. Feeding the World A. Humans and Nutrition Chapter 15 Food and Agriculture Outline is widespread starvation caused by a shortage of food. IE: Ethiopia 1985 drought, war, loss of soil all contributed to poor crops Humans need energy, which comes in the form of. 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. One Calorie (Cal) is equal to 1000 calories or one kilocalorie. 1. Sources of Nutrition is the type and amount of food that one eats. Figure 1: Wood Food Production 2. Diets Around the World People in countries tend to eat more food and a larger proportion of proteins and fats than people eat in countries. B. The Ecology of Food 1. Food Efficiency As human population increased, area dedicated to farmland has increased. Also, different kinds of agriculture have different environmental impacts and different levels of efficiency. of a given type of agriculture is a measure of the quantity of food production on a given area of land with limited inputs of energy and resources. An ideal food crop is one that efficiently produces a of food with little impact on the environment.

2 2 On average, energy, water and land are used to produce a Calorie of food from than to produce a Calorie of food from. Thus area of land can produce more food for humans when it is used for plants than when it is used for raise animals. However, meat from animals generally provides more nutrients per gram than most food from plants. 2. Old and New Foods Organisms can have high --- the amount of food that can be produced in a given area. C. World Food Problems 1. Unequal Distribution Distribution of food worldwide: If all the food in the world was distributed equally to every individual in the world, no one would have enough food to be considered healthy. Here in the US, many people suffer from malnutrition. 2. Droughts and Famines A is a prolonged period when rainfall is below average. A drought is more likely to cause in places where most food is grown locally than in places where most food is imported. Droughts effects can last years and several years of drought cause severe problems for any area of the world. Figure 5: Worldwide Grain Production D. The Green Revolution Worldwide, increases in crop yields resulted from the use of new crop varieties and the application of modern agricultural techniques. These changes were called the -. Most new varieties of grain produce yields only if they received amounts of water, fertilizer, and pesticides.

3 3 In addition, the machinery, irrigation, and chemicals required by these new varieties can degrade the soil. II. Crops and Soil is land that can be used to grow crops. Overtime, this area is shrinking. A. Agriculture: Traditional and Modern Procedures for farming include plowing, fertilization,. These basic techniques have been used for centuries. Modern Agriculture uses inorganic fertilizers and technology. High costs of energy needed: - B. Fertile Soil: the Living Earth Soil that can support the growth of healthy plants is called -. Plant roots grow in top soil, the surface layer of soil, which is usually richer in organic matter than the subsoil. Figure 8. A number of organisms assist in breaking up the soil and. C. Soil Profile= all the horizons Figure 8 pg 385 D. Soil Erosion: A Global Problem is the wearing a way of rock or soil by wind and water. In the US, about half of the original topsoil has been lost o erosion in the past 200 years. E. Land Degradation

4 4 happens when human activity or natural processes damage the land so that it can no longer support the local ecosystem. In areas with dry climates, can result, which is the process by which land in arid or semiarid areas becomes more desert-like because of human activities or climatic changes. F. Soil Conservation No-till Farming and Contour plowing are ways to conserve the soil. 1. Keeps the soil in multiple, small levels 2. Contour plowing= follows the contour of the land 3. Strip cropping 4. (+) saves time for planting (-) soil gets too dense G. Enriching the Soil With the use of inorganic fertilizers, there are some negative consequences. 1) Pesticides and fertilizers get into water 2) 3) Only replaces certain nutrients One way to enrich the soil is composting. Compost is partly decomposed organic matter that comes from many different sources. H. Salinization Accumulation of in the soil is known as salinization. Too much salt can cause plants not to grow. Irrigation can also cause salinization by raising the ground water level temporarily. Once ground water comes near the surface, the ground water is drawn up through the soil like water is drawn up through a sponge. I. Pest Control

5 5 In North America, insects eat about percent of all crops. Pest is any organism that occurs where it is not wanted or occurs in large enough numbers to cause economic damage. I. Pesticides Many farmers rely on to produce their crops. Pesticides are chemicals used to kill. Although pesticides eliminate the pests, they can have a effect on other organisms, including humans. 1. Pesticide resistance= over time insects become immune to the toxin (natural selection) 2. = pesticides are toxic to humans, causes cancer 3. Pollution and persistence= it does not break down easily or quickly in the environment. Example of Pesticides: DDT J. Biological Pest Control Biological Pest control is the use of living organisms to control pests. EX: lady bugs and aphids 1. Pathogens= organisms that cause disease Ex: Bacillus thuringiensis (Bt) bacterium used to kill caterpillars of moths considered to be pests 2. Plant defenses= scientists have bred plant varieties that have defenses against plants EX: VNT tomatoes (resistant to fungi, worms, and viruses) 3. Chemical from plants

6 6 EX: chemicals from chrysanthemum are sold as pesticides, less harmful to humans and pets. 4. Disrupting Insect Breeding Growth regulators are chemicals that interfere with some stages of a pest s life cycle. IE: Frontline Pheromones: chemicals produced by one organism that affect the behavior of another organism IE: Japanese beetle traps. K. Integrated Pest Management Most farmer practice some form of. Integrated pest management is a modern method of controlling pests and crops. Figure 16: shows the steps involved in integrated pest management. L. Engineering a Better Crop Technology in which genetic material in a living cell is modified for medical or industrial use is called genetic engineering. involves isolating genes from one organisms and implanting them into another. In the United States we now eat and use genetically engineered agriculture products. Pros and Cons Pros of Genetic Engineering Cons of Genetic Engineering

7 7 M. Sustainable Agriculture Farming that natural resources and helps keep the land productive indefinitely. III. Animals and Agriculture About animal species have been domesticated, which means that they are bred and managed for human use. IE: chickens, sheep cattle, honey bees, etc. A. Food from Water Catching or removing from a population more organism than the population can replace is called -. Many governments are not trying to stop overharvesting of fish. B. Aquaculture One solution to overharvesting of the fish population is aquaculture. Aquaculture is raising aquatic organisms for human use or consumption. IE: oyster or fish farms. C. Livestock Domesticated animals that are raised to be used on a farm or ranch or to be sold for profit are called Ruminants Cattle, sheep and goats are ruminants, cud-chewing mammals that have three- or four chambered stomachs. When we eat the meat of ruminants,, such as grass stems and woody shrubs, into food that we can digest, such as beef. 2. Poultry Since, the population of chickens worldwide has increased by a greater percentage than the population of any other livestock.

8 8 Chapter 15 Food and Agriculture Outline IV. Feeding the World D. Humans and Nutrition Famine is widespread starvation caused by a shortage of food. IE: Ethiopia 1985 drought, war, loss of soil all contributed to poor crops Humans need energy, which comes in the form of food. Malnutrition 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. One Calorie (Cal) is equal to 1000 calories or one kilocalorie. 3. Sources of Nutrition Diet is the type and amount of food that one eats. Figure 1: Wood Food Production 4. Diets Around the World People in more developed countries tend to eat more food and a larger proportion of proteins and fats than people eat in less developed countries. E. The Ecology of Food 3. Food Efficiency As human population increased, area dedicated to farmland has increased. Also, different kinds of agriculture have different environmental impacts and different levels of efficiency. The efficiency of a given type of agriculture is a measure of the quantity of food production 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.

9 9 On average, more energy, water and land are used to produce a Calorie of food from animals than to produce a Calorie of food from plants. Thus area of land can produce more food for humans when it is used for plants than when it is used for raise animals. However, meat from animals generally provides more nutrients per gram than most food from plants. 4. Old and New Foods Organisms can have high yield-- the amount of food that can be produced in a given area. F. World Food Problems 3. Unequal Distribution Unequal Distribution of food worldwide: If all the food in the world was distributed equally to every individual in the world, no one would have enough food to be considered healthy. Here in the US, many people suffer from malnutrition. 4. Droughts and Famines A drought is a prolonged period when rainfall is below average. A drought is more likely to cause famine in places where most food is grown locally than in places where most food is imported. Droughts effects can last years and several years of drought cause severe problems for any area of the world. Figure 5: Worldwide Grain Production D. The Green Revolution Worldwide, increases in crop yields resulted from the use of new crop varieties and the application of modern agricultural techniques. These changes were called the Green Revolution. Most new varieties of grain produce large yields only if they received large amounts of water, fertilizer, and pesticides.

10 10 In addition, the machinery, irrigation, and chemicals required by these new varieties can degrade the soil. V. Crops and Soil Arable land is land that can be used to grow crops. Overtime, this area is shrinking. J. Agriculture: Traditional and Modern Procedures for farming include plowing, fertilization, irrigation and pest control. These basic techniques have been used for centuries. Modern Agriculture uses inorganic fertilizers and technology. High costs of energy needed: fuel, chemicals, etc. K. Fertile Soil: the Living Earth Soil that can support the growth of healthy plants is called fertile soil. Plant roots grow in top soil, the surface layer of soil, which is usually richer in organic matter than the subsoil. Figure 8. A number of organisms assist in breaking up the soil and allowing air and water it. L. Soil Profile= all the horizons Figure 8 pg 385 M. Soil Erosion: A Global Problem Erosion is the wearing a way of rock or soil by wind and water. In the US, about half of the original topsoil has been lost to erosion in the past 200 years. N. Land Degradation

11 11 Land Degradation happens when human activity or natural processes damage the land so that it can no longer support the local ecosystem. In areas with dry climates, desertification can result, which is the process by which land in arid or semiarid areas becomes more desert-like because of human activities or climatic changes. O. Soil Conservation No-till Farming and Contour plowing are ways to conserve the soil. 5. Terracing Keeps the soil in multiple, small levels 6. Contour plowing= follows the contour of the land 7. Strip cropping 8. No-till farming (+) saves time for planting (-) soil gets too dense P. Enriching the Soil With the use of inorganic fertilizers, there are some negative consequences. 4) Pesticides and fertilizers get into water 5) High energy costs 6) Only replaces certain nutrients One way to enrich the soil is composting. Compost is partly decomposed organic matter that comes from many different sources. Q. Salinization Accumulation of salts in the soil is known as salinization. Too much salt can cause plants not to grow. Irrigation can also cause salinization by raising the ground water level temporarily. Once ground water comes near the surface, the ground water is drawn up through the soil like water is drawn up through a sponge. R. Pest Control

12 12 In North America, insects eat about 13 percent of all crops. Pest is any organism that occurs where it is not wanted or occurs in large enough numbers to cause economic damage. I. Pesticides Many farmers rely on pesticides to produce their crops. Pesticides are chemicals used to kill insects, weeds, and other crop pests. Although pesticides eliminate the pests, they can have a negative effect on other organisms, including humans. 4. Pesticide resistance= over time insects become immune to the toxin (natural selection) 5. Human health concerns= pesticides are toxic to humans, causes cancer 6. Pollution and persistence= it does not break down easily or quickly in the environment. Example of Pesticides: DDT J. Biological Pest Control Biological Pest control is the use of living organisms to control pests. EX: lady bugs and aphids 5. Pathogens= organisms that cause disease Ex: Bacillus thuringiensis (Bt) bacterium used to kill caterpillars of moths considered to be pests 6. Plant defenses= scientists have bred plant varieties that have defenses against plants EX: VNT tomatoes (resistant to fungi, worms, and viruses) 7. Chemical from plants EX: chemicals from chrysanthemum are sold as pesticides, less harmful to humans and pets.

13 13 8. Disrupting Insect Breeding Growth regulators are chemicals that interfere with some stages of a pest s life cycle. IE: Frontline Pheromones: chemicals produced by one organism that affect the behavior of another organism IE: Japanese beetle traps. M. Integrated Pest Management Most farmer practice some form of pest management. Integrated pest management is a modern method of controlling pests and crops. Figure 16: shows the steps involved in integrated pest management. N. Engineering a Better Crop Technology in which genetic material in a living cell is modified for medical or industrial use is called genetic engineering. Genetic engineering involves isolating genes from one organisms and implanting them into another. In the United States we now eat and use genetically engineered agriculture products every day. Pros and Cons Pros of Genetic Engineering Cons of Genetic Engineering

14 14 M. Sustainable Agriculture Farming that conserves natural resources and helps keep the land productive indefinitely. VI. Animals and Agriculture About 50 animal species have been domesticated, which means that they are bred and managed for human use. IE: chickens, sheep cattle, honey bees, etc. D. Food from Water Catching or removing from a population more organism than the population can replace is called overharvesting. Many governments are not trying to stop overharvesting of fish. E. Aquaculture One solution to overharvesting of the fish population is aquaculture. Aquaculture is raising aquatic organisms for human use or consumption. IE: oyster or fish farms. F. Livestock Domesticated animals that are raised to be used on a farm or ranch or to be sold for profit are called livestock. 3. Ruminants Cattle, sheep and goats are ruminants, cud-chewing mammals that have three- or four chambered stomachs. When we eat the meat of ruminants, we are using them to convert plant material, such as grass stems and woody shrubs, into food that we can digest, such as beef. 4. Poultry Since 1961, the population of chickens worldwide has increased by a greater percentage than the population of any other livestock.