IELTSwithJurabek

PASSAGE 2

Read the text and answer questions 14-26

A. 14 Sometime in the early Cretaceous period of the Earth's history, hunting wasps of a certain type became bees by adopting a vegetarian diet: they began to rely more and more on the pollen of plants as a source of protein for themselves and their offspring, as an alternative to insects. In so doing, they accidentally transported pollen on their bodies to other plants of the same species, bringing about pollination. The stage was thus set for a succession of ever-closer mutual adaptations of bees and flowering plants. In particular, flowers began to reward bees for their unwitting role in their reproduction by providing richer sources of pollen and another source of nutrition, nectar.

B. 15 Today about 15 per cent of our diet consists of crops which are pollinated by bees. The meat and other animal products we consume are ultimately derived from bee-pollinated forage crops, and account for another 15 per cent. It follows that around one third of our food is directly or indirectly dependent on the pollinating services of bees. On a global basis, the annual value of agricultural crops dependent on the pollination services of bees is estimated at 1,000 million pounds (US$1,590 million). Much of this pollination is due to honey bees, and in monetary terms it exceeds the value of the annual honey crop by a factor of fifty.

C. Example: vii The pursuit of self-interest

But the apparently harmonious relationship between bees and plants conceals a conflict of interests. Although flowers need bees and vice versa, it pays each partner to minimise its costs and maximise its profits. This may sound like an extreme case of attributing human qualities to non-human species, but using the marketplace and the principles of double-entry book keeping as metaphors may give us some insights into what is really going on between bees and flowering plants. In the real world, both flower and bee operate in a competitive marketplace. A community of retailers, the flowers, seek to attract more or less discriminating consumers, the bees. Each flower has to juggle the costs and benefits of investing in advertising, by colour and scent, and providing rewards, nectar and pollen. Clearly a species which depends on cross-pollination is on a knife-edge: it must provide sufficient nectar to attract the interest of a bee, but not enough to satisfy all of its needs in one visit. A satiated bee would return to its nest rather than visit another flower. The bee, on the other hand, is out to get the maximum amount of pollen and nectar. It must assess the quality and quantity of rewards which are on offer and juggle its energy costs so that it makes a calorific profit on each foraging trip. The apparent harmony between plants and bees is therefore not all that it seems. Instead, it is an equilibrium based on compromises between the competing interests of the protagonists.

D. 16 This sounds remarkably like the ideas of the 18th-century economist Adam Smith. In his book, The Wealth of Nations, Smith postulated that in human society the competitive interactions of different "economic units" eventually resulted in a balanced, or "harmonious" society. One might predict, therefore, that economists would find the relationships between bees and plants of some interest. This is the case in Israel, where economists are collaborating with botanists and entomologists in a long-term study of the pollination biology of the native flora, in an attempt to understand the dynamics of the relationship between communities of bees and plants.

E. 17 This sort of study is of more than passing academic interest. It is important that authorities understand the dynamic relationships between plants and their pollinators. This is especially true when, say, devising conservation policies. A good example comes from the forests of tropical South America. Here, as in all rainforests, there is a high diversity of tree species. There may be more than 120 per acre, but in a given acre there may only be one or two individuals of any one species. These trees are pollinated by large, fast-flying bees. There is evidence that certain types of bees learn the distribution of these scattered trees and forage regularly along the same routes. This is called "trap-lining" and the bees forage for up to 23km from their nests. The bees are therefore acting as long distance pollinators.

F. 18 An issue of current concern in tropical forest conservation is that of trying to estimate the minimum sustainable size of islands of forest reserve in areas where large-scale felling is taking place. There is much discussion on seed dispersal distances. But this is only one half of the equation, so far as the reproduction of trees is concerned. There is another question that must be addressed in order to calculate whether proposed forest reserves are close enough to the nearest large tract of forest: "what is the flight range of these long-distance foragers?" We need to know much more about bees and their relationships with plants before this question can be answered.

G. Bees, then, are vital to our survival. Furthermore, much of the visual impact of human environments derives from vegetation, and most vegetation is dependent on bees for pollination. Thus, as pollinators of crops and natural vegetation, bees occupy key positions in the web of relationships which sustain the living architecture of our planet.

PASSAGE 3

Read the text and answer questions 27-40

A NEW STAGE IN THE STUDY AND TEACHING OF HISTORY

For hundreds of years, historians have relied on written or printed documents to provide the bulk of their source materials, and they have largely communicated with students and the wider public by writing books and journal articles. Today, however, the printed word is being superseded by a diversity of forms of communication, above all moving images on video or film.

A. The development of this new form of communication is leading to a growing gap between the practice of professional historians based in academia, and the practice of those aiming to popularize the study of history among the general public, and to encourage people to create their own records for the future. On the one hand, there are mainstream academics who continue to use only the written word as they examine more and more fields with an ever-increasing number of sophisticated methodologies. On the other hand, film and video, especially as broadcast on television, are probably the major influence on the public's consciousness of history, as they see film of events of fifty or a hundred years ago, events they had previously only read about.

B. In a related development, a great many people now document local and family events in the form of videos; many schools, too, produce video yearbooks. All these visual records may well prove to be invaluable sources of information for future historians. The glaring contradiction is that the two approaches - the academic and what we might term the popular - have intersected very little: with a few notable exceptions, professional historians have tended to avoid involvement in television programmes about history, and have even less impact on what is being captured and preserved on video. And the potential of moving images has wielded negligible influence on the academic study of history.

C. This gulf can be seen as resulting from the willingness or otherwise of individual historians to accept the validity of new forms of communication in the study of history. This is not the first time that the question has arisen. The study of history, as conceived of today, began with the transition from oral to literate culture, leading to the earliest written records and the earliest historical studies. The next great shift came with the advent of printing, which transformed everything. Today, as the printed word loses its dominance, historians are faced with a variety of forms of communication, ranging from simple audiotape to the promising complexities of videodiscs linked with computers. As yet, however, the use of moving images to record current events for the benefit of future historians does not even have a commonly agreed name.

D. This does not mean that mainstream historians have totally rejected the use of moving images as sources: the majority seem intrigued by the idea, and valuable research has been carried out into the history and analysis of films with a broad circulation, using them as a source of information on the social and intellectual history of the twentieth century. Journals such as American History Review have played a significant role in this field.

E. Yet the number of historians using moving images in their research or teaching is very small. The barrier seems to be that the profession is structured around the medium of the written word, and is somewhat insulated in its academic setting. The use of moving images presents a substantial challenge to this setting and its assumptions. As a result, historians have rejected the training, the institutions, the motivations and the professional structures that would be needed in order to use moving images effectively. Above all, they have rejected the necessity to learn complicated new skills.

F. So why should historians make this change? Clearly, films or videos of events and people can be used as solid evidence of the past, linked to the words of the narrator, whether a television presenter/historian or a university teacher giving a lecture, but carrying information in their own right. Film has reintroduced the oral form as a mode of research and communication for documenting historical events. Now, with moving images, people are reminded that oral communication is not limited to words: it also includes body language, expression and tone, and is embedded in a context. Little of this is evident in a written transcript. A further effect of video and film is that the narrator gives up some control and has less need to give explanations, while the viewer becomes involved in the process of interpreting and understanding history.

G. Film or videotape can also aid historians by simplifying the work of the interviewer. Instead of trying to carry on an interview while simultaneously making notes about setting and other unspoken data, this new kind of historian can concentrate on the interview itself, and study the film later. The many benefits of using moving images as historical evidence easily outweigh worries about cost, technical skills, or the effect of a camera on a person telling his or her story. Moving images enhance the quality of historical research, and suggest new directions for historians to explore.