environmentalstudyguide

environmentalstudyguide - Human Population-Population...

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Human Population -Population profile shows number of males and females at each age interval -Population projection -Project per capita birth rate for each population segment -Project per capita death rate for each population segment -Use population profile for segment population -Calculate new profile, ageing and adding births and subtracting deaths Appropriate to each segment. -Demographic Transition -Generally as a country increases in development, death rate decreases before birth rate. Birth rate decrease follows. -Country goes from equilibrium of high birth and death rate to equilibrium of low birth and death rate. -During trasition, population growth can be explosive Food -Challenges in feeding the world -Hunger, malnutrition, undernourishment -Food production -Food distribution -Undernourishment: Insufficient food calories -Malnutrition: Lack of essential protein, vitamins or minerals -Biochemistry -Carbohydrates and fats are mainly energy stores. They have some other functions such as in cell membranes, cellulose structures, etc. -Proteins are working molecules. -Proteins are combinations of amino acids. -There are 20 amino acids. Given nitrogen, humans can make 11 of them. The other 9 are called “essential” and must be taken in from food. -Biochemistry Digestion -The process of digestion breaks down food molecules. -Some of the digestion products move through the cell walls of the digestive tract and into the blood stream. These include amino acids, simple sugars, fatty acids, and dissolved vitamins and minerals. -Large molecules do not normally pass into the blood stream. They are either broken down or excreted. -Malnutrition -We must obtain directly from food: -essential amino acids -nitrogen -minerals which contain other atoms necessary for the manufacture of amino acids -minerals and vitamins necessary for protein function -Absence of these essentials in a diet will create malnutrition, a condition of low body function in spite of adequate calories. -Solubility -some vitamins(and other chemicals) are fat soluble. They can be stored in the
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body’s fat cells for use when needed. Others are water soluble. These must be consumed regularly, they are not stored. -Diet must be balanced to include all necessary essential elements. Can be tricky with vegetarian diet. Traditional diets work. (corn and beans, rice and beans) -Subsistence Agriculture -Land intensive. More so for diet based on animal products. -Challenge: increase production per acre -Food Production History -Subsistence agriculture -Transition to modern agriculture -“Green Revolution” -Biotechnology—“genetic engineering” -Transition to Modern Agriculture -Irrigation -Machinery -Pesticides and fertilizers -High yield plant (animal) varieties -Biotechnology—genetic engineering -high yield plants or animals -new proteins or proteins new to an organism through DNA manipulation (gene splicing) -Benefit plant: help overcome environmental resistance. To come… -Modify food product. Now… -Modified food product -Golden Rice: Designed to add beta carotene and iron to seed. Normally present
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environmentalstudyguide - Human Population-Population...

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