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如何写biology essay Coffee And Its Global Applications

Results and Discussion

In the study done by Berthou, Mathieu and Vedel in 1983 chloroplast and mitochondrial DNA from nine species of coffee-trees were compared to their phylogenetic relationship by restriction endonuclease fragment analysis. Three types of cp DNA were discovered with the following relationship: 1) C. arabica, C. eugenioides; 2) C. canephora, C. congensis, “nana” taxon; 3) C. liberica. The mt DNA separated into five types: 1) C. arabica, C. eugenioides, C. congensis; 2) C. canephora, “nana” taxon; 3) C. excelsa; 4) C. liberica; 5) Paraeoffea ebracteolata. C. arabica is the only tetraploid species (2n=44) that is self fertile, while all other species are diploids (2n=22) and self incompatible. So the study suggests that C. arabica evolved from a cross between two wild diploid species (Berthou et al 1983).

With the advances in technology a more recent study was done, which was able to identify the coffee species that gave rise to the world known C. arabica. The results obtained from Restriction Fragment Length Polymorphism (RFLP) markers and combination of genomic in situ hybridization (GISH) suggests that C. arabica is an amphidiploid formed by hybridization between C. eugenioides and C. canephora. Also the results showed low divergence between genomes of C. arabica and its progenitor, which implies recent speciation of C. arabica (Lashermes et al 1999).

There are two genetic bases of C. arabica Typica and Bourbon, which have spread from Yemen in 18th century and have given rise to most C. arabica cultivars grown world-wide. In the study done by Anthony and colleagues eleven C. arabica accessions from disseminated bases were evaluated by AFLP using 37 primer combinations and SSRs produced by six microsatellites. The results of the study confirmed the Ethiopian origin of the Typica and Bourbon genetic bases; also the reduction of the genetic diversity with dissemination of the crop was observed (Anthony et al 2001). C. arabica has a center of diversity in the southwestern Ethiopia highlands (Sylvain 1955). According to Vavilov the center of diversity is the center of domestication. These two evidences are pointing to the same center, which is Ethiopia.

This decrease in the genetic diversity is posing a danger for the crop. In the history the coffee has been already threatened by Hemileia vastatrix. In 1869 this fungus appeared in Ceylon and destroyed most of the plantations (Wikipedia). The fungus is causing orange rust on the leaves, the areas where fungus attacks through stomata; no damage is done to fruits or stem. This damage reduces photosynthesis rate and leaf drop at high infection levels (Ferreira and Boley, 1991). The decrease in the genetic diversity is also a sign of domestication, which usually leads to the genetic uniformity. As the plant moved farther away from its origin it is moved farther away from the center of its genetic diversity. Also during transportation the whole trees were transported, so only limited amount of population representatives were selected. And finally during the long voyages when water became scare not all trees survived to reach the destination. According to McDonald coffee shrubs were obtained from seed planters of Batavia, and one of these shrubs was sent to Botanical Gardens at Amsterdam. Seeds from this plant were planted in the New World, and so from one coffee plant disseminated world known plantations of South and Central America which produce three quarters of the world’s coffee production (McDonald 1930). This explains why the AFLP study showed that current C. arabica cultivars have very narrow genetic diversity.

In the beginning, the coffee trees were distributed among the forests on the highlands of Kenya and Abyssinia (current Ethiopia). The coffee plant was first observed in Caffa (hence its name), a district of Southern Abyssinia (Arnold 1886). These forests provided sustenance to the native tribes and the coffee trees have been very useful. The ripe cherries from the wild coffee trees were crushed in stone mortars and mixed the pulp with animal fat; then they were rounded into balls and ate it during travel (Uribe 1954). The coffee origin stories can also be found in the western literature. The myth of Kaldi the Ethiopian goatherd and his dancing goats is one of the most popular examples. The story describes that Kaldi noticed the energizing effects of red berries on his flock and tried the fruit himself. Then he brought the fruits to the holy man in the monastery. The holy man disapproved the use of the berries and threw them into fire. When the aroma filled the air the roasted coffee beans were taken out of the fire and mixed with water. Another origin story, describes a civet cat and how the animal carried wild coffee seeds from central Africa to Ethiopian mountains, where the plant was first cultivated in Arusi and Ilta-Gallas (Weinberg and Bealer, 2001). These two stories are imaginary, but some conclusions can be drawn from them in determining the origin of coffee and culture of coffee drinking.

The imaginative historians can find recordings of coffee beans in the Old Testament. When Abigail brought presents to ease David’s wrath, according to I Samuel, Chapter 25, verse 18, she carried five measures of parched corn, which might have been coffee (Uribe 1954). Several evidences are pointing to Ethiopia as the origin of coffee, but what dissemination course did the crop take from its origin? Also the origin of the coffee is not the major producer of coffee worldwide and some major uses can be made of coffee diversity gathered in Ethiopia.

From Ethiopia at the beginning of the 14th century the coffee was introduced along the old caravan routes to Yemen, in Arabia (Arnold 1886). It is possible that coffee plantations have been planted in Yemen by Ethiopians invaders during fifty years of their rule in the sixth century (Pendergrast 2010). The coffee was first publicly used at Aden in Arabia Felix about the middle of the ninth century, after it quickly spread to Makkah, Madina, Egypt, Syria and other parts of the Levant and has always been the topic of controversy (McDonald 1930). The controversy was caused by the teachings of the Koran and the effects of coffee on people. There is written evidence that there was an attempt to prohibit coffee consumption in Mecca in 1511 (Hattox 1985). But this mention of coffee prohibition does not point to the first ever controversy, this could be the first recorded issue with coffee consumption and it is not known of any previous controversies.

First mention of a plant that could be coffee in print is dated tenth century by Persian physician Rhazes (865-925 CE), in a medical text he wrote about bunn and a drink called buncham. Around 1000 CE Avicenna, another Arab physician also wrote about buncham, he wrote “It fortifies the members, cleans the skin, and dries up the humidities that are under it, and gives an excellent smell to all the body” (Pendergrast 2010). But these two works by Rhazes and Avicenna have some controversy since it is not clear that these Arab physicians are writing about coffee plant and not something else. In the 16th century the coffee has been introduced to Turks, the coffee was shipped from Mocha and overland by caravans to Damascus and Aleppo (Arnold 1886). Long before the coffee reached the Europe it was mostly grown in the Arabian Peninsula and it became a fashionable drink in Cairo and Istanbul (Bulbeck et al 1998). But around 1615 coffee was introduced into Venice, since it was a port and Venetians had sailed every sea and visited all lands exporting great products from the Levant, Africa and the Indies to Europe (Uribe 1954). The term often associated with coffee is “Java”, which is an island in Indonesia. Coffee was introduced from Arabia to Java at about 1690 by Dutch (McDonald 1930).

The first coffee grown in America was introduced into Surinam by Dutch in 1718. De Clieu a naval officer in 1720 introduced the coffee plant into Martinique, Guadeloupe and other French islands. In 1730 Sir Nicholas Lawes first grew it in Jamaica, and it is known that coffee cultivation extended to Ceylon, the West Indies and Brazil (Arnold 1886). And that’s the history of coffee dissemination out of its origin in Ethiopia. These are historical accounts of when the coffee was first introduced to other locations and how successful was its cultivation.

Kahwah is the name of coffee in the Arabic language, the Turks called it Capee and these two words probably were the origin of the English word Coffee. The name is of the beverage and not the plant (Hull 1877). Also the coffee seeds are often called Coffee “beans”, not because they resemble beans, but as written in “Champers’s Encyclopedia” the word comes from Arabic word bunn (Hull 1877). The linguistic evidences are pointing to the fact that the Arab world has been introduced to the coffee before everyone else and Arabs have named the plant. Linnaeus labeled the plant Coffea arabica, because Arabs were first to plant coffee as a cash crop (Bulbeck et al 1998). Also as mentioned previously the coffee was first observed in the region of Ethiopia called Caffa, which may also contributed to the name of the crop.

There is only limited archaeological data on the origin of coffee. The Kafa Archaelogical Project (2004-2006) excavated ten caves and rockshelters in southwestern Ethiopia. The study has showed that pottery and domestic stock were present locally by 2,000 BP. Some sites provided substantial quantities of desiccated plants, at least two partial seeds of Coffea arabica have been excavated in levels above the 1,740 BP date (Hildebrand et al 2010). The researchers speculate that this excavation is the first macrobotanical evidence for such economically important plant in archaeological context. At another site the first Haysi pottery shards suggest that coffee was used by Sufis in a ritual around 1,450 BP (Wild 2005). But also according to Anthony Wild the recent discovery of two carbonized coffee beans in an archaeological dig at Kush in the United Arab Emirates may bring early coffee history in question. In 1996, British archaeologists performed excavation at the Kush site and found pottery layer and the two carbonized coffee beans. With the use of flotation machine the beans were identified as Coffea Arabica, which had been preserved only because they had fallen into a fire and preliminary dated the finding as early 1100s (Wild 2005). Anthony Wild speculates that this finding will provide concrete evidence of the existence of coffee in the early 1100s and possibility of coffee beans roasting before consumption, since they have been in close proximity to fire. But these findings have not been finalized and still need to be re-analyzed.

Art can also be used as evidence in finding the origin of a crop. The following diagrams (from Hattox 1985) illustrate historical coffee consumption and botanical identification of the plant. Figure 1 illustrates a late seventeenth-century engraving of a coffee tree. Figure 2 illustrates engraving of the branch of a coffee plant, below are depictions of the matured coffee fruit on the stem, a detail of the fruit, both whole and in cross-section, and the separated kernel. European interest in coffee in the 16th and 17th was scientific and on the voyage that the engraving was made they were trying to cultivate the coffee plant for commercial purposes in the Caribbean (Hattox 1985). Figure 3 depicts a Turk holding a cup of coffee, at the bottom of the picture is coffee plant and coffee mill. This coffee mill was already used in the Near East and is similar to the one still used in Turkey today (Hattox 1985). Figure 4 depicts Turkish miniature from the mid-sixteenth century showing a wide range of activities common to the coffeehouse. Coffeehouses and their history is a valuable evidence of dissemination of the coffee from its origin. As the miniature depicts the first coffeehouses appeared in Turkey, and as the coffee spread to Europe the coffeehouses has followed.


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