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Reading Test 30
A Brief / The History of Tea
The story of tea begins in China. According to legend, in 2737 BC, the Chinese emperor Shen Nung was sitting beneath a tree while his servant boiled drinking water, when some leaves from the tree blew into the water. Shen Nung, a renowned herbalist, decided to try the infusion that his servant had accidentally created. The tree was a Camellia sinensis, and the resulting drink was what we now call tea.
It is impossible to know whether there is any truth in this story. But tea drinking certainly became established in China many centuries before it had even been heard of in the West. Containers for tea have been found in tombs dating from the Han Dynasty (206 BC–220 AD) but it was under the Tang Dynasty (618–906 AD), that tea became firmly established as the national drink of China.
It became such a favourite that during the late eighth century a writer called Lu Yu wrote the first book entirely about tea, the Ch’a Ching, or Tea Classic. It was shortly after this that tea was first introduced to Japan, by Japanese Buddhist monks who had travelled to China to study. Tea received almost instant royal approval in Japan and spread rapidly from the royal court and monasteries to the other sections of Japanese society.
So at this stage in the history of tea, Europe was rather lagging behind. In the latter half of the sixteenth century there are the first brief mentions of tea as a drink among Europeans. These are mostly travellers, who have lived in the East as traders and missionaries. But although some of these individuals may have brought back samples of tea to their native country, it was not the Portuguese who were the first to ship back tea as a commercial import.
This was done by the Dutch, who in the last years of the sixteenth century began to encroach on Portuguese trading routes in the East. By the early seventeenth century they had established a trading post on the island of Java, and it was Java that in 1606 the first consignment of tea was shipped from China to Holland. Tea soon became a fashionable drink among the Dutch, and from there spread to other countries in western Europe. But because of its high price it remained a drink for the wealthy.
Britain, always a little suspicious of continental trends, had yet to become the nation of tea drinkers that it is today. Starting in 1600, the British East India Company had a monopoly on importing goods from outside Europe, and it is likely that sailors on these ships brought tea home as gifts. The first coffee house had been established in London in 1652, and tea was still somewhat unknown as a drink. Indeed, so it is fair to assume that the drink was still something of a curiosity.
Gradually, it became a popular drink in coffee houses, which were as much locations for the dissemination of business as they were for relaxation or pleasure. They were though the preserve of men, and upper-class men at that, since the entrance fee was no less than the cost of two days’ wages for a labourer. Women’s growing involvement in tea drinking in seventeenth century was somewhat delayed, in part since it was an expensive drink. But by the early eighteenth century, tea was becoming increasingly popular among the working classes. In part, its high price was due to a punitive 5 million lbs!
Worse for die drinkers was that taxation also encouraged the adulteration of tea, particularly of smuggled tea which was not quality controlled through customs and excise. Leaves from other plants, or leaves which had already been brewed and then dried, were added to tea leaves. By 1784, the government realised that enough was enough, and that heavy taxation was creating more problems than it was worth. The new Prime Minister, William Pitt the Younger, slashed the tax from 119 per cent to 12.5 per cent. Suddenly legal tea was affordable, and smuggling stopped virtually overnight.
Another great impetus to tea drinking resulted from the end of the East India Company’s monopoly on the tea trade with China, in 1834. Before that date, China was the only country of origin of the vast majority of tea imported to Britain, but the end of its monopoly stimulated the East India Company to consider growing tea outside China. India had always been the center of the Company’s operations, which led to the increased cultivation of tea in India, beginning in Assam. There were a few false starts, including the destruction by cattle of one of the earliest tea nurseries, but by 1888 British tea imports from India were for the first time greater than those from China.
The end of the East India Company’s monopoly on tea with China also had another result, which was more dramatic though less important in the long term: it ushered in the era of the tea clippers. While the Company had had the monopoly on tea trade, there was no rush to bring the tea from China to Britain, but after 1834 the tea trade became a virtual free-for-all.
Individual merchants and sea captains with their own ships raced to bring home the tea and make the most money, using fast new tea clippers which had sleek lines, tall masts and huge sails. In particular there was competition between British and American merchants, leading to the famous clipper races of the 1860s. But these races soon came to an end with the opening of the Suez Canal, which made the trade routes to China viable for steamships for the first time.
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Biodiversity
A
It seems biodiversity has become a buzzword beloved of politicians, conservationists, protesters and scientists alike. But what exactly is it? The Convention on Biological Diversity, an international agreement to conserve and share the planet’s biological riches, provides a good working definition: biodiversity comprises every form of life, from the smallest microbe to the largest animal or plant; the genes that give them their specific characteristics and the ecosystems of which they are part.
In October, the World Conservation Union (also known as the IUCN) published its updated Red List of Threatened Species, a roll call of 11,167 creatures facing extinction — 121 more than the list was last published in 2000. But the new figures almost certainly underestimate the crisis. Some 1.2 million species of animal and 270,000 species of plant have been classified, but the well-being of only a fraction has been assessed. The resources are simply not available. The IUCN reports that 5714 plants are threatened, for example, but admit that only 4 per cent of known plants has been assessed. And, of course, there are thousands of species that we have yet to discover. Many of these would also be facing extinction.
B
It is important to develop a picture of the diversity of life on Earth now so that comparisons can be made in the future and trends identified. But it isn’t necessary to observe every single type of organism in an area to get a snapshot of the health of the ecosystem. In many habitats, there are species that are particularly susceptible to shifting conditions, and these can be used as indicator species.
C
In the media, it is usually large, charismatic animals such as pandas, elephants, tigers and whales that get all the attention when a loss of biodiversity is discussed. However, animals further down the food chain are often the ones vital for preserving habitats — in the process saving the skins of those more glamorous species. There are known as keystone species.
By studying the complex feeding relationships within habitats, species can be identified that have an overriding importance on the environment. For example, one of the members of the family are the staple food of hundreds of different species in many different countries, and important that scientists sometimes call figs “jungle burgers”. A whole range of animals, from monkeys and birds to bats and insects, feed on everything from the tree’s bark and leaves to its flowers and fruits. Many fig species have very specific pollinators. There are 800 varieties of fig, many in Costa Rica, and a different type of wasp has evolved to pollinate almost every one of them. Chris Lyle of the Natural History Museum in London — who is also involved in the Global Taxonomy Initiative of the Convention on Biological Diversity — believes that their importance and influence on other organisms makes figs keystone species, and any other species associated with them would be enormous.
D
Sea otters also play a major role in the survival of giant kelp forests along the coasts of California and Alaska. These “marine rainforests” provide a home for a wide range of sea creatures. The kelp itself is the main food of purple and red sea urchins, and sea otters prey on urchins in vast numbers by predators, particularly sea otters. They detach an urchin from the seabed then float to the surface and lie on their backs with the urchins on their tummy, smashing it open with a stone before eating the contents. Urchins that are not eaten tend to spend their time in rock crevices to avoid the predators. This allows the kelp to grow — and it can grow many centimeters in a day. As the forests form, bits of kelp break off and fall to the bottom to provide food for the urchins in their crevices. The sea otters thrive on the plentiful sea urchins in the kelp, and other fish and invertebrates live among the fronds. The problems start when the sea otter population declines. As large predators they are vulnerable — their numbers are relatively small to disease or human hunters who can wipe them out. The result is that the sea urchin population grows unchecked and they roam the seafloor, grazing away kelp fronds. This tends to keep the kelp very short and stops forests developing, which has a huge impact on biodiversity.
E
Conversely, keystone species can also make dangerous alien species: they can wreak havoc if they end up in the wrong ecosystem. The cactus moth, whose caterpillar is a voracious eater of prickly pear was introduced to Australia to control the rampant cactus. It was so successful that someone thought it would be a good idea to introduce it to Caribbean islands that had the same problem. It solved the cactus menace, but unfortunately, some of the moths have now reached the US mainland — borne on winds and in tourists’ luggage — where they are devastating the native cactus populations of Florida.
F
Organisations like the Convention on Biological Diversity work with groups such as the UN and with governments and scientists to raise awareness and fund research. A number of important international meetings — including the World Summit on Sustainable Development in Johannesburg this year — have set targets for governments around the world to slow the loss of biodiversity. And CITES meeting in Santiago last month added several more names to its list of endangered species for which trade is controlled. Of course, these agreements can only be effective if countries enforce them.
G
There is cause for optimism, however. There seems to be a growing understanding of the need for sustainable agriculture and sustainable tourism to conserve biodiversity. Problems such as illegal logging are being tackled through sustainable forestry programmes, with the emphasis on minimising the use of rainforest hardwoods in the developed world and on ensuring that only trees grown in plantations are harvested. CITES is playing its part by controlling the trade in goods derived from endangered species. In the same way, sustainable farming practices that minimise environmental damage and avoid monoculture.
H
Action at a national level often means investing in public education and awareness. Getting people to understand biodiversity can be very effective. Australia and many European countries have become increasingly efficient at recycling much of their domestic waste, for example, preserving natural resources and reducing the use of fossil fuels. Thus, in many countries, the amount of greenhouse gas emitted from home energy and landfill sites. Preserving ecosystems and stopping forest clearance are also important. Variety may be the “spice of life”, but biological variety is also our life-support system.
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Nature works Polylactic acid
A dozen years ago, scientists at Cargill got the idea of converting lactic acid made from corn into plastic while examining possible new uses for materials produced from wet milling processes. In the past, several efforts had been made to develop plastics from lactic acid, but with limited success. However, this technological breakthrough didn’t come easily, but in time the efforts succeeded. A new distillation and distillation process using corn was designed to create a polymer suitable for a broad variety of applications.
B
As an agricultural based firm, Cargill had taken this product as far as it could by 1997. The company needed a partner with access to plastics markets and polymerization capabilities, and began discussions with The Dow Chemical Company. The next step was the formation of the joint venture that created Cargill Dow LLC. Cargill Dow’s product is the world’s first commercially available plastic made from annually renewable resources such as corn. Nature Works™ PLA is a family of packaging polymers (carbon-based molecules) made from non-petroleum based resources. Ingeo is a family of polymers for fibers made in a similar manner.
C
By applying their unique technology to the processing of natural plant sugars, Cargill Dow has created an entirely new environmentally friendly material that has the economics to compete with cups, packaging and other products. While Cargill Dow is a stand-alone business, it continues to leverage the agricultural processing, manufacturing and polymer expertise of the two parent companies in order to bring the best possible products to market.
D
The basic raw materials for PLA are carbon dioxide and water. Growing plants, like corn, take these building blocks from the atmosphere and the soil. They are combined in the plant to make carbohydrates (sucrose and starch) through a process driven by photosynthesis. The process for making Nature Works PLA begins when a wet milling process separates starch from milled corn, separating starch from the raw material. Unrefined dextrose, in turn, is processed from the starch.
E
Cargill Dow turns the unrefined dextrose into lactic acid using a fermentation process adapted from the process used to produce cheese and yogurt. This lactic acid is the basic building block of PLA. The food additive acid is found in muscle tissues in the human body. Through a special condensation process, a lactide is formed. The lactide is purified through a vacuum distillation to form a polymer (the base for NatureWorks PLA) that is ready for use through a solvent-free melt process. Nature Works™ polymers are then ready to be formed into plastic granules. Carbon is stored in plant starches, which can be broken down into natural sugar that can be fermented. The carbon in these natural sugars are then used to make Nature Works PLA.
F
Nature Works PLA fits all disposal systems and is fully compostable in commercial composting facilities. With the proper infrastructure, products made from this polymer can be recycled, incinerated or even home-used as compost. Thus, at the end of its life cycle, products made with Nature Works PLA can be broken down into its simplest parts so that no waste remains.
G
PLA is now actively competing with traditional materials in packaging and other applications throughout the world; based on the technology’s success and promise, Cargill Dow is quickly becoming a premier player in the polymers market. The polymer now competes head-on with petroleum-based materials like polyester. A wide range of products that vary in molecular weight and crystallinity can be produced, and the blend of physical properties of PLA makes it suited for a broad range of fiber and packaging applications. Fiber and non-woven applications include clothing, fiberfill, blankets and wipes. Packaging applications include packaging films and food and beverage containers.
H
As Nature Works PLA polymers are more oil- and grease-resistant and provide a better aroma and barrier than existing petroleum-based polymers, grocery retailers are increasingly using this packaging for their fresh foods. As companies begin to explore the full family of polymers, more potential applications are being identified. For example, PLA possesses two properties that are particularly suited for drapery fabrics and window furnishings. Their resistance to ultraviolet light is particularly appealing as this reduces the amount of fading in such fabrics, and their moisture barrier is low, which means fabrics constructed from these polymers can be made with deep colors without requiring large amounts of dye. In addition, sportswear makers have been drawn to the product as it has an inherent ability to take moisture away from the skin when blended with cotton and wool, the result is garments that are lighter and better at absorbing moisture.
I
PLA combines inexpensive large-scale fermentation with chemical processing to produce a value-added polymer product that improves the environment as well. The source material for PLA is a natural sugar found in plant life such as corn and using such renewable feedstock presents several environmental benefits. As an alternative to traditional petroleum-based polymers, the production of PLA uses 20%-50% less fossil fuel and releases a lower amount of greenhouse gases than comparable petroleum-based plastic; carbon dioxide in the atmosphere is removed when the feedstock is grown and is returned to the earth when the polymer is degraded. Because the company is using raw materials that can be regenerated year after year, it is both cost-competitive and environmentally responsible.
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