Resources, Energy, and Human Life



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Resources, Energy, and Human Life

  • Life Science 2010
  • 鄭先祐(Ayo) 製作

Resources, Energy and Human Life

  • Renewable resources(再生資源)
  • non-renewable resources(不可再生的資源)
  • 可轉移的資源
  • 不可轉移的資源

人類目前面臨的問題:

  • 人類目前面臨的問題:
  • 1. 地球上的人口快速的擴張。We are placing a severe and increasing demand on our earthly goods.
  • 2. The Earth's resources are unequally divided.
  • Fig. 28.1 The gold mining operations in South Africa.
  • This country is blessed with approximately 55 percent of the world's supply of gold. The country also has unusual amounts of chromium and diamonds.

Cooperation or confrontations

  • The unequal distribution of the Earth's resources should provide us, one would think, with a marvelous opportunity to achieve world through the mutual dependence of trade.
  • But instead of this, it seems as if it has set the stage for international confrontations.

Food and the present crisis

  • 有些國家糧食供應充裕,許多人民體重過重,營養過剩。有些人則要追求健康食品,如有機蔬菜。
  • Fig. 28.2 many people seed health through better diets. Some are drawn to labels like "organically grown" and "natural", although the terms have no scientific meaning and can be misleading.

Fig. 28.3 Children stricken with Marasmus (a) and kwashiorkor(b)

  • Marasmus is caused by a diet low in both calories and protein.
  • Kwashiorkor results from protein deficiency. Both conditions can permanently impair the victims, both physically and mentally.
  • (a)
  • (b)

Essay 28.1 How hunger kills

美國人的狀況

  • Most Americans have a surprising store of food in their own bodies.
  • The average U.S. citizen weighing 155 pounds has about 35 pounds of stored fat and can go about three months without food.
  • An obese person with 175 pounds of stored fat can theoretically go without food for a year, if the only consideration is calories.

When someone goes without food

  • The first stored food he draws on is the readily available stored glycogen in his liver and muscle.
  • Then to use stored fat.
  • At about this time, the starving body begins to break down protein.
  • Finally, the body's muscle begin to wither, including the heart muscle.

When someone goes without food

  • On the average, people are considered to be starving when they have lost about 33 % of their body weight.
  • When they have lost 40 %, death is almost inevitable.
  • Children are often permanently affected since improved diet cannot straighten bones or build normal brain cells, but adults can largely recover.

The problem of food production

  • There are over 80,000 species of plants known to be edible.
  • But only 16 plants yield almost all the calories and three-fourths of the protein that humans receive from plants.
  • The rest of the edible species are almost ignored, even in the face of hunger and starvation.

Food supply

  • The worldwide distribution of food is very uneven.
  • Not only are there poor, hungry countries, and rich, well-fed ones, but the same country may have rich and poor parts.
  • The problem is partly one of distribution and allocation. The rich have more than their share, the poor have less.

Food supply

  • Each day, the 500,000 owned dogs in New York City testify to good diets by depositing 90,000 gallons of urine and 150,000 pounds of feces on the city's streets.

Fig. 28.4 Much of the Earth's rainforests are destroyed each year for farming and ranching.

Fig. 28.5 The soil in tropical rainforest is notoriously poor. Local farmers will plant a few crops here, then move on.

Essay 28.2 The food pyramid

Should we feed grain to beef cattle or should we eat the grain?

Fig. 28.6 Hogs are raised as food in many parts of the world because they can eat what humans eat.

Fig. 28.7 These jungle fowl of Southeast Asia are being raised for their meat. Both American poultry ranchers and Asian farmers recognize the efficiency of raising poultry for food.

Fig. 28.8 Our increasing efficient fishing technology has resulted in more fish being taken each year. We must now ask how long it can go on.

Fig. 28.9 Ethical questions will arise as more and more people enter an increasingly drained planet. The average family in Bangladesh is reported to have seven children.

Essay 28.3 Miracle crops and the green revolution

  • In the late 1960s, there was a great fanfare heralding the impending "green revolution".
  • New kinds of grains had been developed that yielded plants heavy with seed.
  • For example, one strain of dwarf rice, IR-8, produced over twice as many rice grains per plant as the conventional strains.
  • The new miracle crops do hold great promise for the world's populations. However, they have their problems.

1. The new strains require special handling; farmers must carefully be trained in new agricultural methods.

  • 1. The new strains require special handling; farmers must carefully be trained in new agricultural methods.
  • 2. Miracle crops also must be heavily fertilized and fertilizers, of course, costs money.
  • 3. Then there is the problem of the fertilizer runoff. 優養化,魚獲減少。
  • 4. 易受病虫傷害。譬如:In 1969, specially developed high-yield corn plants were attacked by a new type of fungus called the southern corn blight.

Fig. 28.10 Our total water supply. Most freshwater is frozen in glaciers and ice caps. A minuscule amount(0.003% of the to total) exists as vapor in the atmosphere.

Fig. 28.11 The dry reservoir at Kensico, New York, poignantly illustrates the Earth's continuing problem with a dependable supply of freshwater. Perhaps such problems would be of less magnitude if we realized just how much water we actually use.

Each American uses an average of 2,000 gallons of water each day

  • Each American uses an average of 2,000 gallons of water each day
  • A bath takes 30 to 20 gallons, and five-minute shower, 25 gallons.
  • Less obvious use includes 40 gallons of water goes into the production of a single egg, 75 gallons into 1 pound of flour, 150 gallons into a loaf of bread, 2,500 gallons into a pound of beef, 230gallons into a gallon of bourbon(酒), 280 gallons into a Sunday newspaper, and 100,000 gallons into a car.

Fig. 28.12 Changing water supply in the continental United States.

Nonrenewable resources

  • Nonrenewable resources exist in a fixed amount.
  • When we're out, we're out; They cannot be replaced.
  • Examples include aluminum, iron, and copper.
  • Normally, a nonrenewable resource is considered depleted when 80% of its estimated supply is gone.

Recycling of aluminum cans

  • Just over half the aluminum cans produced in the United States are recycled from old cans turned in at over 5,000 recycling centers nationwide.
  • At about a penny a can, those who sold cans at these centers were recently calculated to have mad about $100 million.

Still, of the more than 80 billion aluminum cans made in the United Sates each year, almost half are simply discarded.

  • Still, of the more than 80 billion aluminum cans made in the United Sates each year, almost half are simply discarded.
  • If the cans Americans throw away in a single year were lad end to end, they would reach to the moon and back about eight times.
  • Researchers had found that Americans will recycle these cans if they are paid a minimum of 5 cents per can.

Recycling reduces pollution

  • Recycling aluminum takes only 5 percent of the energy necessary to mine and process aluminum ore, and it produces only about 5 percent of both air and water pollution.
  • Using scrap iron, instead of virgin iron from the Earth, requires 65% less energy and produces 85% less air pollution and 75% less water pollution.

Recycling of plastics

  • Plastics are only partly degradable.
  • They break down into smaller pieces of plastic, and many may release poisonous products.
  • By the year 2000, it is estimated that about 45% of all plastic waste produced in the United States could be recycled.
  • Even now, recycled plastic costs two-thirds as much as virgin plastic.

Diapers

  • About 18 billion disposable diapers are produced annually worldwide and, in the United States, virtually all of them end up in a landfill where, it is estimated, they will take 500 years to decompose.
  • It also costs American taxpayers about $375 million a year to dispose of them.
  • 若是使用cloth diapers,則需要耗水和耗電。

Energy

  • Fig. 28.13 The good life for many people is based quite simply on more goods and services.

Fig. 28.14 Estimated average daily per capita energy use at various stages of human cultural evolution.

Energy form fossil fuels

  • Fig. 28.15 Americans feverishly pump out every drop of oil they can locate, ignoring the simple truth that it cannot be replenished.

Essay 28.4 The true cost of gasoline

  • In the USA gasoline is dirt cheap.
  • Why is gasoline so cheap in USA?
  • It's because they don't pay the real price of gasoline. They pay a discounted price.

Essay 28.5 The greenhouse effect

Essay 28.5 The greenhouse effect

  • If greenhouse gases continue to rise at the current rate, between 2030 and 2050, the average temperature on Earth will rise by about 1.5oC to 10oC.
  • If the temperature should rise 4oC, these scientists forecast massive changes in weather and ocean currents.

Energy from water

  • Fig. 28.16 Even the tides have been harnessed to provide people with inexpensive energy. Such sources have the great advantage of being renewable and nonpolluting.

Energy from the wind

  • Fig. 28.17 These unsightly and surprisingly noisy windmills produce electrical energy efficiently and without heavy pollution.

Energy from the Earth

  • Fig. 28.18 Geothermal power plants utilize the heat energy of the Earth's interior to generate electricity.

Energy from the Sun

  • Fig. 28.19 Sunlight falls on collecting panels and the energy is then used for heating water and, space, or generating electricity.

Fig. 28.20 The areas of greatest oil and gas production also have the greatest sunlight levels.

Fig. 28.21 In passive solar systems such as this one, sunlight warms air and water, which are then distributed by natural expansion, contraction, and convection. The stone wall stores heat, which radiates into the house. Here, heated air moves out into the rest of the house.

Energy from the Atom

  • The touting nuclear power argue that it will reduce our dependence on foreign oil and that it will reduce the greenhouse effect by lowering the amount of pollution caused by burning fossil fuels.
  • Neither argument is entirely sound.
  • 1. We use most oil to make gasoline for our cars. Only 3 percent of our electricity comes from burning oil. So, even if we built nuclear plants to provide electricity, we would still need to import oil.
  • 2. It has been calculated that, in order to reduce the world's greenhouse effect by only 2 %, we would have to build a large reactor every day for the next 37 years.

Economic disasters

  • Think about this one.
  • The Tennessee Valley Authority, in 1994, cancelled the last three nuclear power plants still under construction in the United States, after spending decades -- and billions of dollars -- on the projects.
  • See chap. 29 for more discussion

Encouraging conservation and increasing efficiency

  • Fig. 28.23 Features of a well-insulated home.
  • 1. Our homes should be well insulated and we may want to build them in convenient neighborhoods from which we do not have to travel far on a daily basis.
  • 2. We can develop a new set of habits.
  • 3. We should have a powerful recycling ethic.
  • 4. We should encourage, perhaps through revised loan practices and tax incentives, the research and development necessary to produce better devices.

Fig. 28.24 The various fates of the waste we generate.

  • 80%掩埋
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  • 問題與討論!
  • japalura@hotmail.com
  • Ayo NUTN website: http://myweb.nutn.edu.tw/~hycheng/


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