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Reading Test 54
Scented Plants
A
Many plants emit a smell. This may come from the flower of the plant, from the leaves, stem, or even, in some cases, from the root. What humans may perceive as a fragrant perfume is actually a tool used by plants to entice pollinators, discourage bacteria or fend off predators. Fragrances consist of small organic particles with high vapor pressures, so that a scent compound evaporates easily if exposed to the air; chemicals which evaporate in this way are described as volatile compounds.
B
Although we generally think of plant odors as pleasant, many volatile compounds in plants are toxic when eaten. These compounds are used by plants to protect themselves from bacterial attack. Humans have recognized and taken advantage of these plant-derived antibacterials since antiquity, when they were used to slow the spoilage of food. For example, the spice clove could be used to bake goods and preserves to slow the growth of mould and bacteria because a small amount was not dangerous to humans. Before the development of modern food preservation techniques, European civilization was heavily dependent on cloves and other tropical spices to ensure a long-lasting supply of food. However, the long distance from Europe to South-east Asia made these spices extremely expensive and was part of the motivation behind the search for a shorter route to Asia which resulted in the discovery of the Americas.
C
Although volatile compounds in plants probably originally evolved to repel herbivorous (plant-eating) animals of all kinds, they now perform a remarkable range of functions. An important one common to many plants is to attract animals which will spread that plant’s pollen. Insects are the most common animals to interact with plants in this way, and most insects detect volatile compounds through the extremely sensitive antennae on their heads. Some antennae can detect an airborne volatile compound at concentrations of just a few parts per billion.
D
Other plants emit volatile compounds which function as toxins against invading insects, and still others emit such compounds when they have been injured, in order to deter insects from laying eggs on them and thus injuring them further. Volatile compounds released by plants in response to herbivore egg laying, for example, can attract parasites of the eggs, thereby preventing them from hatching. In this way the plant can avoid the attack of the hungry young herbivores that would have emerged from the eggs.
E
Volatile compounds in plants can also be used as a kind of currency in some very indirect defensive systems. In the rainforest tree Leonardoxa africana, for example, the volatile compounds called extrafloral nectaries attract young leaves because they emit higher levels of the volatile compound methyl salicylate, a substance that ants need to use as an antiseptic in their nests; coincidentally, the ants attack any herbivorous insects they encounter. It appears that methyl salicylate both attracts ants and rewards them for performing their valuable role in deterring herbivores. The web of interactions among plants and animals can become so complicated that it is difficult to detect what the outcome of the release of volatile compounds is. But it is clear that the system can have a defensive purpose, as many experiments have shown that the deactivation of a plant’s volatile emission system makes it more vulnerable to herbivores.
F
Floral scent has a strong impact on the economic success of many agricultural crops that rely on insect pollinators, including fruit trees such as the bee-pollinated cherry, apple, apricot and peach, as well as vegetables and tropical plants such as papaya. A decrease in fragrance emission, due to crossbreeding for fruit size or other characteristics, reduces the ability of plants to attract pollinators and may result in considerable losses for growers. This problem has been made worse in the United States by recent epidemics that have infected and killed many honeybees, the major insect pollinator.
G
Some plant breeders have tried to solve this pollination crisis by spraying scent compounds on orchard trees to enhance honeybee foraging, but this approach was costly, and in the end proved to be inefficient. One of the reasons for its ineffectiveness was that general spraying of the crop could not tell insects exactly where the blossoms were. Clearly, a more refined strategy is needed; genetic manipulation of scents, for example, would allow growers to regulate the types of insect pollinators and the frequency of their visits.
H
Such manipulation of scent will also benefit people who grow flowers commercially. Cut flowers and potted plants play an important aesthetic part in human life. Unfortunately, traditional breeding has produced varieties with improved vase life, color and shape, while perfume has been sacrificed. The loss of scent among ornamental flowers, which have a worldwide annual value of more than US$30 billion, makes them important targets for the genetic manipulation of flower fragrance. Some preliminary experiments have already been carried out, but for technical reasons the scent was present in every part of the plant, rather than being localized in the flower, and the level of intensity of fragrance was below the threshold of detection for human nose. The next generation of experiments, already in progress, will include more sophisticated schemes that target the expression of scent specifically to flowers or other organs, such as special glands that can store antibacterial or herbivore-repellent compounds.
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What is an unfair advantage in sport?
Olympic athletes increasingly depend on technology to help them win—but is that fair?
A
What happened to the Australian athlete Ron Clarke in the 10,000 metres at the Mexico City Olympics of 1968 is now virtually forgotten, though at the time it was headline news. Clarke was the greatest distance runner in history—held more world records than anybody else. But in front of 55,000 horrified spectators, the event went disastrously wrong. In the third lap, one runner keeled over, and with six laps to go, two more were carried away. Yet the race was being conducted at a relatively leisurely speed: the halfway time was the slowest since the Paris Olympics of 1924.
With two laps to go, Clarke was in the leading pack. “I’d never felt better in a race,” he says. But suddenly, he began to struggle, and as the frontrunners moved up a gear, a gap opened up. Clarke remembers nothing of his last lap, which he ran in 90 seconds. “Normally I would run it in 64,” he explains. He staggered across the line in sixth place and collapsed. He was administered oxygen and stretchered off the track.
B
Mexico City is surrounded by mountains and is over 2,240 metres above sea level. That altitude would have an impact on the Games was predicted. Clarke had raised the issue himself but had been told by the Australian sports authorities that complaining was regarded as bad sportsmanship. As it turned out, he had good reason to do so. Clearly, the link between athletic performance and altitude needed further investigation.
C
Although there were few standout performances in distance running at the Mexico Games, they marked a turning point: the start of an astonishing record of success by East Africans. While Clarke lay crumpled in a heap, runners from Kenya and Ethiopia were celebrating their gold and silver medals. The record books confirm how entrenched this pattern has become. The names of the seven fastest men in history over 5,000 metres are Bekele, Gebrselassie, Kom en, Kipchoge, Sihine, Songok, and Cherono. They are all from either Kenya or Ethiopia. Between 1997 and 2011, the 10,000 metres men’s world record was smashed five times, dropping from 26:31.32 to 26:17.53. Each time, the record was broken by a Kenyan or an Ethiopian.
D
At high altitudes, a number of physiological alterations occur, most importantly, more red blood cells and haemoglobin are produced. This, in turn, increases the capacity of the blood to carry oxygen, which feeds the muscles and gives an advantage to the athletes when they return to sea level. However, it is impossible to train with the same level of intensity in the mountains—both capacity and cardio-respiratory function are lower at altitude. As a result, the consensus is that the optimum approach to athletic preparation is: Live High, Train Low (LHTL). Yet, that has obvious practical drawbacks. Not many people live in the mountains, and those who do would prefer not to spend several hours each day driving up and down winding, treacherous roads.
E
That’s where altitude tents—sometimes called the hypoxic tent—comes in. Around two decades ago, two different scientists had the same exciting thought. If they could artificially control the atmosphere within a confined space, they could simulate the effects of high altitude and save an athlete at sea level from the time and expense of traveling to higher ground. Athletes tents have improved over the years: they’re not as hot or as noisy as the early prototypes, and are much cheaper too. They are also perfectly lawful. Five years ago, when the tents were investigated by WADA (the World Anti-Doping Agency), it was ruled they did not violate the spirit of distance running. It is now routine for athletes to sleep in them in preparation for an event.
F
However, it is not the case that all new technologies gain approval. In 2008, a staggering 105 world records were broken in swimming, the vast majority achieved by competitors wearing the Speedo LZR racer suit. These suits use a high-tech fabric tested in NASA’s wind tunnels, which reduces drag and improves buoyancy. The LZR was initially sanctioned by FINA, the international swimming body. But as better suits were produced by Speedo and other manufacturers, and more records were broken, they became increasingly controversial. In 2009, FINA changed its mind, banning all suits made with this high-tech fabric.
G
Going faster, higher, stronger is integral to the logic of athletics in general, and the Olympics in particular. Athletes believe they need records all the time. And the only way they can achieve records is by improving their clothing, the kit, the training, the nutrition—all to identify minute distinctions between people of 0.0001 of a second. But when a new technology is invented, the relevant sports authority has to consider whether to embrace or reject it. In some cases, athletes are granted permission to use the technology; in others, it is banned. But whatever the outcome, rulings should not appear arbitrary. Arguments have to be examined and weighed, and the rule logic ought to apply in every case.
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Finland's Primary Education System
US university lecturer William Doyle examines the Finnish approach to schooling
According to a recent World Economic Forum Global Competitiveness report, Finland has the best primary school system in the world. In order to see this for myself and compare it to the system in the US, I visited the University of Eastern Finland’s teacher training school in Joensuu where the emphasis is on personalised learning.
In many educational institutions across the world, including the US, the emphasis is on discipline and competition. Standardised testing has been introduced, but has failed to lift students’ academic performance to any significant degree. In contrast, classrooms in Joensuu had much less of a focus on testing but were remarkable for their warmth, regular praise from teachers, and students being encouraged to reflect on their own performance.
In some nations, there has been a rush towards “one device per student”, with claims these can offer personalised learning. In fact, this trend flies in the face of Organisation for Economic Co-operation and Development (OECD) study that found little academic benefit for children from most classroom technology. In Joensuu, there isn’t a tablet in sight: just a smartboard and a teacher’s desktop. Instead, teachers address their students, sometimes from the front of the class, but also as they visit each desk in turn to ask and answer questions. This kind of communication with individual students is vital if they are to acquire knowledge and develop their abilities.
In Joensuu, as in other Finnish schools, teachers are not restricted by excessive regulations, but have the freedom to try out new approaches to improve learning; a system which clearly works. The biggest innovations are “self-assessments”, where students write daily narratives on their progress. Teachers are also experimenting with peer assessments, where children are carefully guided to offer constructive suggestions to classmates. While some of Finland’s approaches might not be a good fit for educational systems in other countries, this particular concept is certainly something educational reformers in the US could consider.
One teacher I observed is Jussi Hietava, who works with a fourth-grade class while simultaneously mentoring trainee teachers as they learn the required skills. Unlike the US, where thousands of teacher positions are filled by candidates fresh from a six-week course, no teacher in Finland may lead a primary school class without a master’s degree in education, from one of its eleven graduate schools of education. Hietava once dreamed of becoming an airline pilot, but it wasn’t to be. Instead, he entered an even more respected profession, teaching, the most admired job in Finland next to medical doctors. The authorities in countries around the world could take note.
Now, after watching Finnish educators in action, I realise Finland’s historic achievements in delivering educational excellence to its children result from a deep understanding of how children learn best. Children are given instruction not only in maths, language and science, but also in arts, crafts, music and ethics. The homework load for children varies from teacher to teacher, but is lighter than in most other developed countries. This insight is supported by research, which finds little academic benefit from any more than brief sessions of homework until admission to high school.
There are, of course, criticisms of the Finnish education system. Sceptics point out that its schools are facing huge budget pressures, reading levels among children have, apparently, dropped off, and anecdotal evidence suggests that advanced learners can be bored. These things must not be ignored. There is also a view that Finland’s success is simply a “Nordic thing”, meaning that all children from Finland, Norway, Sweden, Iceland and Denmark have a positive attitude to learning, and will learn irrespective of the learning environment they are in. But Finland significantly out-achieves its neighbouring countries in academic performance, this makes no sense.
In the US, some school principals and administrators in the Department of Education have argued that the Finnish approach to learning wouldn’t work in US inner-city schools, as children are from diverse cultural backgrounds and lower socio-economic groups. But what if the opposite is true? Finland’s size, immigration and income levels are roughly similar to those of a number of US states, and it is at state level that most education policy is implemented. Some ideas about classroom procedure may not always be transferable, but a good number of them could easily be employed by countries around the world. In fact, children in high-poverty areas might be the ones to benefit most.
Another Finnish school I visited was in North Karelia. Head of the school is Heikki Happonen. As laughing children run down the hall into the cafeteria, he hands out high-fives. According to Happonen, the hallway scene reveals a secret about Finland’s historic success in childhood education: children’s brains work better when they are moving. The result is that they are more successful at negotiating, building teams and friendships.
Furthermore, they can focus for longer on what they are studying. Finland also recognises that play is fundamental to children’s learning. They learn through play until age seven, and are allowed 15 minutes rest time every hour of every single school day until high school.
“Children must feel like school is a home for them,” says Happonen. He explains that primary school should be a place where children can feel important, with teachers expressing admiration for their qualities and unique skills, and the children, in turn, looking up to their teachers as role models. In addition, Happonen designed much of the school building at Torkk Karelia himself because he wanted there to be a network of traditional classrooms linked by spacious hallways, soft lighting and large couches for children to relax on. There is also an extensive library of books and magazines, since children are encouraged to take an interest in a wide range of topics, and this is added to each week. What child wouldn’t want to come to school here?
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