ISB 202 1nd Edition Lecture 18 Outline of Last Lecture I. Environmental HealthOutline of Current Lecture II. Food and AgricultureIII. Green RevolutionIV. Increases and DecreasesV. Over-NutritionCurrent LectureFood and Agriculture World food supplies have kept up with human population growth over the past two centuries.– During the past 40 years, population growth has averaged 1.7% per year, while food production increased an average 2.2%. Bioaccumulation is a term that describes the way cells:– Grow as they absorb all types of molecules– Selectively absorb and store molecules often in fatty tissues– Accumulate food stores as fat– Metabolize compounds that are absorbed– Allow water-soluble compounds to pass through membranes The bio-magnification of DDT (pesticide) demonstrates that:– Higher trophic level organisms concentrate higher levels of toxins in their tissues– Birds should not depend on fish for food– DDT is easily metabolized and excreted by most organismsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.– DDT is an extremely water-soluble material– Water-soluble toxins are widespread An LD50 is a dose of a toxic chemical that:– Is an acceptable level of risk for most individuals– All individuals react to– Kills individuals 50 years old and over– Is 50 times less than the minimal dose– Kills half of the populationGreen Revolution Most major improvements in farm production have come from technological advances and modification of a few well-known species.– Corn yields jumped from 25 bushels per acre to 130 per acre in last century. Most of gain accomplished through conventional plant breeding Green Revolution started by Norm Borlaug. Dwarf, high yielding wheat and rice grown around the world. Borlaug won a Nobel Peace Prize. Green revolution plants require fertilizers and protection from pests. If these are lacking, modern crops may not produce as well as traditional crops. Poor farmers may be left out of the green revolution. Crops of green revolution grow in temperate climates. Efforts underway to create new crops for tropical climates.Improvements and Decreases In 1960, 60% of the population of developing countries was considered chronically undernourished.– Fallen to less than 14% today Food Prices are Increasing– There are 923m undernourished people in the world– Most of the world’s hungry are a direct result of high food prices– A report by the UK-based charity also found that spiraling inflation in the cost of basic foods such as rice and cereals had pushed an extra 119 million people into hunger this year. Poverty: 2.1 Billion people live on less than $2.00/day, 880 million on less than $1.00/day– Operates on multiple levels– Recognizing role of women in food production is an important step forward. Famines are characterized by large-scale food shortages, massive starvation, social disruption, and economic chaos.– Mass migrations often occur because of food famine– Environmental conditions are an immediate trigger, but armed conflict and political oppression are the underlying causes.The Right Kinds of Food Malnourishment - nutritional imbalance caused by a lack of specific dietary components or an inability to absorb or utilize essential nutrients– 3 billion people suffer from vitamin, mineral or protein deficiency.– Results in illness, reduced mental capacity, developmental abnormality, stunted growth, death Iron deficiency is the most common dietary imbalance in the world.– Leads to anemia, insufficient hemoglobin in the blood Increases risk of death from hemorrhage in childbirth and affects development Red meat, eggs, legumes, and green vegetables are all good sources of iron. Lack of iodine leads to goiter as well as stunted growth and reduced mental capacity. Lack of vitamin A affects as many as 140 million children and 350,000 go blind each year.Over-nutrition People in rich countries eat too much meat, salt, sugar and saturated fat and not enoughfiber, vitamins, and minerals. On average, we consume 33% more calories than we need. 62% of Americans are overweight. Obesity is spreading around the world as other people adopt Western
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