Presentation on theme: "Food and Agriculture Feeding a hungry planet. Test Your Knowledge: T or F? Agriculture is a declining industry and its importance is decreasing because."— Presentation transcript:
Test Your Knowledge: T or F? Agriculture is a declining industry and its importance is decreasing because of its lower contribution to GNP and employment. FALSE: In fact, Agriculture is important because everybody eats food and lower income groups spend a large portion of their income on food. Nutritious food benefits everyone. Food production problems have been solved. Food prices are lower and there are surpluses. FALSE: Although new production technologies have increased harvest yield, they create new ecological and economic concerns. World food demand will increase with urbanization, increasing population, and rising income levels. Agriculture can only be destructive/harmful to ecosystems and natural resources. FALSE: New approaches to agriculture, including integrated pest management and more sophisticated understanding of production techniques, can have positive impacts on natural systems.
Test Your Knowledge: T or F? Insects are harmful and eliminating them will benefit humans. FALSE: It’s true that many insects eat plants and can affect plant production. However, the elimination of some insect pests has disrupted natural predator-prey systems and resulted in decreased food production. The addition of more nutrients automatically results in increased food production. FALSE: More isn’t always better. More nutrients can lead to eutrophication. Instead, careful and systematic use of fertilizers can result in increased production without increasing fertilizer application.
Reading Objectives Understand the physical constraints on food production Explain the key inputs required for sustained crop yield Discuss the challenges and advances in increasing yields Describe the challenges encountered in controlling pest since the early 20 th century Describe the challenges in growing animals for food Discuss the benefits and challenges of Genetic modification of agricultural products Discuss energy issues in agriculture Discuss advances in sustainable agriculture Discuss the challenges in feeding a growing population
Food, Nutrition, Hunger 800 million people are undernourished, 95% of them live in developing countries, mostly Africa and Asia Agricultural production is impacted by weather, agricultural mismanagment, and sociopolitical crises Famine: large scale food shortages triggered by hurricanes, tsunamis, insects Lead to starvation, disruption, migration
Case Studies Wangari Maathai – Green Belt Movement Wangari Maathai World Hunger: Past, Present, Future summarize World Hunger: Past, Present, Future
Human Nutritional Requirements To thrive and survive, people need: Dietary Energy Proteins Carbohydrates Dietary Fats Vitamins Minerals Malnutrition or malnourishment is a lack of specific nutrients in the diet, although there may be enough calories http://www.fao.org/docrep/007/y5686e/y5686e00.htm
Diseases Half the world’s population suffers from some vitamin, mineral or protein deficiency Kwakshiorkor – lack of protein, enough carbs Marasmus – low in protein and calories Goiter - iodine Rickets – Calcium, Vitamin D Beriberi – Vitamin B1 Pellagra – Vitamin B3 Scurvy – Vitamin C Anemia - Iron Obesity – low nutrient content with overabundance of calories
Food sources Legumes, cereals, grains, nuts and seeds, fruits make up plant proteins Wheat, rice, corn are primary grains Eight animals make up people’s protein supply Large scale livestock farming consists of penning animals in high concentration – leads to waste production and disease Antibiotics are overused leading to antibiotic resistance
Farm Policy Farmers are paid subsidies by the government, which can create imbalance in commodity value and affordability
Soil Review O – organic, leaf litter, etc A – Topsoil is where insects and organic matter are concentrated. If topsoil erodes away, plants cannot grow. E – zone of leaching B – can support roots but does not have organic matter C – parent material from weathered bedrock
Soil types A mixture of clay, silt and sand provides proper aeration (space for seeds to sprout and roots to grow), infiltration (movement of water so nutrients can dissolve), and support.
Soil degredation Erosion caused by wind, weather Human activity – Removing crops from soil (extracts nutrients) Excessive use of irrigation salinization Excessive use of pesticides, herbicides Monoculture lack of biodiversity overgrazing
Reading and Video http://www.learner.org/courses/envsci/un it/text.php?unit=7&secNum=1 http://www.learner.org/courses/envsci/un it/text.php?unit=7&secNum=1 Go to your assigned section; take notes and prepare to communicate what you learned.
Biomagnification Objectives Participants will develop an understanding of why some toxicants (such as pesticides) bioaccumulate. Most chemicals that bioaccumulate dissolve in lipids and therefore are not excreted but stay in body tissue
Biomagnification Materials Oil Fishing pole 16 test tubesRed dye Red marker 1- liter beaker 5 - 100 ml beakers Pipettes 2 - 400 ml beakers Stirring rods (one per participant) Fish consumption advisories
Bioaccumulation Procedure Some chemicals accumulate in the fat of animals, like the pesticide DDT that was used to kill Insects in order to protect crops. ZOOPLANKTON: 16 participants will represent zooplankton. Each will get a test tube that contains 3 parts water and 1 part oil. These layers represent the fat and water in the organism. LITTLE FISH: 4 participants will be little fish. Each will get one 100 ml beaker. BIG FISH: 2 participants will be big fish. Each will get one 400 ml beaker. FISHERPERSON: 1participant will be a fisherman/woman. This person gets the fishing pole and a 1 liter beaker. The solution you see is made of red dye and oil and it represents a fat soluble pesticide chemical like DDT
Biomagnification Activity “While the zooplankton were feeding on algae, they digested 4 drops of pesticide. These 4 drops did not kill them or make them sick. However, more then 7 drops would have.” Zooplanktons: Put 4 drops of the “pesticide” in your test tube and stir. Notice the “pesticide” stays in the oil. “Each little fish will eat 4 zooplankton.” Little fish: Pour the contents of 4 zooplankton into your beaker. Keep track of the amount of “pesticide” in each little fish. “Each big fish will eat 2 little fish.” Big fish: Pour the contents of 2 little fish into your beaker. Keep track of the amount of “pesticide” in the fish.
Discussion The angler catches and eats two big fish. How many drops of “pesticide” are in the human? It takes 80 drops to kill or make the human sick. How many more infected fish could this human safely eat? Why are pesticides are used in agriculture? Are there other ways to grow crops without using pesticides?
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