Tổng hợp topic Environment (Biology, Agriculture,...) IELTS READING (PDF)(Phần 5)

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II. Tổng hợp topic Environment (Biology, Agriculture,...) IELTS READING (PDF) (Phần 5)

53. Bài 53

Climate change reveals ancient artefacts in Norway’s glaciers

A. Well above the treeline in Norway’s highest mountains, ancient fields of ice are shrinking as Earth’s climate warms. As the ice has vanished, it has been giving up the treasures it has preserved in cold storage for the last 6,000 years – items such as ancient arrows and skis from Viking Age* traders. And those artefacts have provided archaeologists with some surprising insights into how ancient Norwegians made their livings.

B. Organic materials like textiles and hides are relatively rare finds at archaeological sites. This is because unless they’re protected from the microorganisms that cause decay, they tend no to last long. Extreme cold is one reliable way to keep artefacts relatively fresh for a few thousand years, but once thawed out, these materials experience degradation relatively swiftly.

With climate change shrinking ice cover around the world, glacial archaeologists need to race the clock to find newly revealed artefacts, preserve them, and study them. If something fragile dries and is windblown it might very soon be lost to science, or an arrow might be exposed and then covered again by the next snow and remain well-preserved. The unpredictability means that glacial archaeologists have to be systematic in their approach to fieldwork.

C. Over a nine-year period, a team of archaeologists, which included Lars Pilø of Oppland County Council, Norway, and James Barrett of the McDonald Institute for Archaeological Research, surveyed patches of ice in Oppland, an area of south-central Norway that is home to some of the country’s highest mountains. Reindeer once congregated on these ice patches in the later summer months to escape biting insects, and from the late Stone Age**, hunters followed. In addition, trade routes threaded through the mountain passes of Oppland, linking settlements in Norway to the rest of Europe.

The slow but steady movement of glaciers tends to destroy anything at their bases, so the team focused on stationary patches of ice, mostly above 1,400 metres. That ice is found amid fields of frost-weathered boulders, fallen rocks, and exposed bedrock that for nine months of the year is buried beneath snow.

‘Fieldwork is hard work – hiking with all our equipment, often camping on permafrost – but very rewarding. You’re rescuing the archaeology, bringing the melting ice to wider attention, discovering a unique environmental history and really connecting with the natural environment,’ says Barrett.

D. At the edges of the contracting ice patches, archaeologists found more than 2,000 artefacts, which formed a material record that ran from 4,000 BCE to the beginnings of the Renaissance in the 14th century. Many of the artefacts are associated with hunting. Hunters would have easily misplaced arrows and they often discarded broken bows rather than take them all the way home. Other items could have been used by hunters traversing the high mountain passes of Oppland: all-purpose items like tools, skis, and horse tack.

E. Barrett’s team radiocarbon-dated 153 of the artefacts and compared those dates to the timing of major environmental changes in the region – such as periods of cooling or warming – and major social and economic shifts – such as the growth of farming settlements and the spread of international trade networks leading up to the Viking Age. They found that some periods had produced lots of artefacts, which indicates that people had been pretty active in the mountains during those times. But there were few or no signs of activity during other periods.

F. What was surprising, according to Barrett, was the timing of these periods. Oppland’s mountains present daunting terrain and in periods of extreme cold, glaciers could block the higher mountain passes and make travel in the upper reaches of the mountains extremely difficult. Archaeologists assumed people would stick to lower elevations during a time like the Late Antique Little Ice Age, a short period of deeper-than-usual cold from about 536-600 CE. But it turned out that hunters kept regularly venturing into the mountains even when the climate turned cold, based on the amount of stuff they had apparently dropped there.

‘Remarkably, though, the finds from the ice may have continued through this period, perhaps suggesting that the importance of mountain hunting increased to supplement failing agricultural harvests in times of low temperatures,’ says Barrett. A colder turn in the Scandinavian climate would likely have meant widespread crop failures, so more people would have depended on hunting to make up for those losses.

G. Many of the artefacts Barrett’s team recovered date from the beginning of the Viking Age, the 700s through to the 900s CE. Trade networks connecting Scandinavia with Europe and the Middle East were expanding around this time. Although we usually think of ships when we think of Scandinavian expansion, these recent discoveries show that plenty of goods travelled on overland routes, like the mountain passes of Oppland. And growing Norwegian towns, along with export markets, would have created a booming demand for hides to fight off the cold, as well as antlers to make useful things like combs. Business must have been good for hunters.

H. Norway’s mountains are probably still hiding a lot of history – and prehistory – in remote ice patches. When Barrett’s team looked at the dates for their sample of 153 artefacts, they noticed a gap with almost no artefacts from about 3,800 to 2,200 BCE. In fact, archaeological finds from that period are rare all over Norway. The researchers say that could be because many of those artefacts have already disintegrated or are still frozen in the ice. That means archaeologists could be extracting some of those artefacts from retreating ice in years to come.

*Viking Age: a period of European history from around 700 CE to around 1050 CE when Scandinavian Vikings migrated throughout Europe by means of trade and warfare

**The Stone Age: a period in early history that began about 3.4 million years ago

Questions 14-19
Reading Passage 2 has eight sections, A-H.

Which section contains the following information?

Write the correct number, A-H, in boxes 14-19 on your answer sheet.
14.   an explanation for weapons being left behind in the mountains

15.   a reference to the physical difficulties involved in an archaeological expedition

16.   an explanation of why less food may have been available
17.   a reference to the possibility of future archaeological discoveries

18.   examples of items that would have been traded

19.   a reference to the pressure archaeologists are under to work quickly

Questions 20-22
Complete the summary below. Choose ONE WORD ONLY from the passage for each answer. Write your answers in boxes 20-22 on your answer sheet.

Interesting finds at an archaeological site

Organic materials such as animal skins and textiles are not discovered very often at archaeological sites. They have little protection against 20 …………………, which means that they decay relatively quickly. But this is not always the case. If temperatures are low enough, fragile artefacts can be preserved for thousands of years.

A team of archaeologists have been working in the mountains in Oppland in Norway to recover artefacts revealed by shrinking ice cover. In the past, there were trade routes through these mountains and 21 ………………… gathered there in the summer months to avoid being attacked by 22 ………………… on lower ground. The people who used these mountains left things behind and it is those objects that are of interest to archaeologists.

Questions 23 and 24
Choose TWO letters, A-E. Write the correct letters in boxes 23 and 24 on your answer sheet.

Which TWO of the following statements does the writer make about the discoveries of Barrett’s team?

A.   Artefacts found in the higher mountain passes were limited to skiing equipment.

B.   Hunters went into the mountains even during periods of extreme cold.

C.   The number of artefacts from certain time periods was relatively low.

D.   Radiocarbon dating of artefacts produced some unreliable results.

E.   More artefacts were found in Oppland than at any other mountain site.

Questions 25 and 26
Choose TWO letters, A-E. Write the correct letters in boxes 25 and 26 on your answer sheet.

Which TWO of the following statements does the writer make about the Viking Age?

A.   Hunters at this time benefited from an increased demand for goods.

B.   The beginning of the period saw the greatest growth in the wealth of Vikings.

C.   Vikings did not rely on ships alone to transport goods.

D.   Norwegian towns at this time attracted traders from around the world.

E.   Vikings were primarily interested in their trading links with the Middle East.

54. Bài 54

Plant ‘thermometer’ triggers springtime growth by measuring night-time heat

A photoreceptor molecule in plant cells has been found to have a second job as a thermometer after dark – allowing plants to read seasonal temperature changes. Scientists say the discovery could help breed crops that are more resilient to the temperatures expected to result from climate change.

A. An international team of scientists led by the University of Cambridge has discovered that the ‘thermometer’ molecule in plants enables them to develop according to seasonal temperature changes. Researchers have revealed that molecules called phytochromes – used by plants to detect light during the day – actually change their function in darkness to become cellular temperature gauges that measure the heat of the night.

The new findings, published in the journal Science, show that phytochromes control genetic switches in response to temperature as well as light to dictate plant development.

B. At night, these molecules change states, and the pace at which they change is ‘directly proportional to temperature’, say scientists, who compare phytochromes to mercury in a thermometer. The warmer it is, the faster the molecular change – stimulating plant growth.

C. Farmers and gardeners have known for hundreds of years how responsive plants are to temperature: warm winters cause many trees and flowers to bud early, something humans have long used to predict weather and harvest times for the coming year. The latest research pinpoints for the first time a molecular mechanism in plants that reacts to temperature – often triggering the buds of spring we long to see at the end of winter.

D. With weather and temperatures set to become ever more unpredictable due to climate change, researchers say the discovery that this light-sensing molecule also functions as the internal thermometer in plant cells could help us breed tougher crops. ‘It is estimated that agricultural yields will need to double by 2050, but climate change is a major threat to achieving this. Key crops such as wheat and rice are sensitive to high temperatures. Thermal stress reduces crop yields by around 10% for every one degree increase in temperature,’ says lead researcher Dr Philip Wigge from Cambridge’s Sainsbury Laboratory. ‘Discovering the molecules that allow plants to sense temperature has the potential to accelerate the breeding of crops resilient to thermal stress and climate change.’

E. In their active state, phytochrome molecules bind themselves to DNA to restrict plant growth. During the day, sunlight activates the molecules, slowing down growth. If a plant finds itself in shade, phytochromes are quickly inactivated – enabling it to grow faster to find sunlight again. This is how plants compete to escape each other’s shade. ‘Light-driven changes to phytochrome activity occur very fast, in less than a second,’ says Wigge.

At night, however, it’s a different story. Instead of a rapid deactivation following sundown, the molecules gradually change from their active to inactive state. This is called ‘dark reversion’. ‘Just as mercury rises in a thermometer, the rate at which phytochromes revert to their inactive state during the night is a direct measure of temperature,’ says Wigge.

F. ‘The lower the temperature, the slower the rate at which phytochromes revert to inactivity, so the molecules spend more time in their active, growth-suppressing state. This is why plants are slower to grow in winter. Warm temperatures accelerate dark reversion, so that phytochromes rapidly reach an inactive state and detach themselves from the plant’s DNA – allowing genes to be expressed and plant growth to resume.’ Wigge believes phytochrome thermo-sensing evolved at a later stage, and co-opted the biological network already used for light-based growth during the downtime of night.

G. Some plants mainly use day length as an indicator of the reason. Other species, such as daffodils, have considerable temperature sensitivity, and can flower months in advance during a warm winter. In fact, the discovery of the dual role of phytochromes provides the science behind a well-known rhyme long used to predict the coming season: oak before ash we’ll have a plash, ash before oak we’re in for a soak.

Wigge explains: ‘Oak trees rely much more on temperature, likely using phytochromes as thermometers to dictate development, whereas ash trees rely on measuring day length to determine their seasonal timing. A warmer spring, and consequently a higher likeliness of a hot summer, will result in oak leafing before ash. A cold spring will see the opposite. As the British know only too well, a colder summer is likely to be a rain-soaked one.’

H. The new findings are the culmination of twelve years of research involving scientists from Germany, Argentina and the US, as well as the Cambridge team. The work was done in a model system, using a mustard plant called Arabidopsis, but Wigge says the phytochrome genes necessary for temperature sensing are found in crop plants as well. ‘Recent advances in plant genetics now mean that scientists are able to rapidly identify the genes controlling these processes in crop plants, and even alter their activity using precise molecular “scalpels”,’ adds Wigge. ‘Cambridge is uniquely well-positioned to do this kind of research as we have outstanding collaborators nearby who work on more applied aspects of plant biology, and can help us transfer this new knowledge into the field.’

Questions 27-32

Do the following statements agree with the information given in Reading Passage 3? In boxes 27-32 on your answer sheet, write:

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this
27. The Cambridge scientists’ discovery of the ‘thermometer molecule’ caused surprise among other scientists.

28. The target for agricultural production by 2050 could be missed.

29. Wheat and rice suffer from a rise in temperatures.

30. It may be possible to develop crops that require less water.

31. Plants grow faster in sunlight than in shade.

32. Phytochromes change their state at the same speed day and night.

Questions 33-37
Reading Passage 3 has eight sections, A-H.

Which section contains the following information?

Write the correct letter, A-H, in boxes 33-37 on your answer sheet.
33. mention of specialists who can make use of the research findings

34. a reference to a potential benefit of the research findings

35. scientific support for a traditional saying

36. a reference to people traditionally making plans based on plant behaviour

37. a reference to where the research has been reported

Questions 38-40
Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 38-40 on your answer sheet.
38. Daffodils are likely to flower early in response to ………………….. weather.

39. If ash trees come into leaf before oak trees, the weather in ………………….. will probably be wet.

40. The research was carried out using a particular species of ………………….. .

55. Bài 55

The Dead Sea Scrolls

In late 1946 or early 1947, three Bedouin teenagers were tending their goats and sheep near the ancient settlement of Qumran, located on the northwest shore of the Dead Sea in what is now known as the West Bank. One of these young shepherds tossed a rock into an opening on the side of a cliff and was surprised to hear a shattering sound. He and his companions later entered the cave and stumbled across a collection of large clay jars, seven of which contained scrolls with writing on them. The teenagers took the seven scrolls to a nearby town where they were sold for a small sum to a local antiquities dealer. Word of the find spread, and Bedouins and archaeologists eventually unearthed tens of thousands of additional scroll fragments from 10 nearby caves; together they make up between 800 and 900 manuscripts. It soon became clear that this was one of the greatest archaeological discoveries ever made.

The origin of the Dead Sea Scrolls, which were written around 2,000 years ago between 150 BCE and 70 CE, is still the subject of scholarly debate even today. According to the prevailing theory, they are the work of a population that inhabited the area until Roman troops destroyed the settlement around 70 CE. The area was known as Judea at that time, and the people are thought to have belonged to a group called the Essenes, a devout Jewish sect.

The majority of the texts on the Dead Sea Scrolls are in Hebrew, with some fragments written in an ancient version of its alphabet thought to have fallen out of use in the fifth century BCE. But there are other languages as well. Some scrolls are in Aramaic, the language spoken by many inhabitants of the region from the sixth century BCE to the siege of Jerusalem in 70 CE. In addition, several texts feature translations of the Hebrew Bible into Greek.

The Dead Sea Scrolls include fragments from every book of the Old Testament of the Bible except for the Book of Esther. The only entire book of the Hebrew Bible preserved among the manuscripts from Qumran is Isaiah; this copy, dated to the first century BCE, is considered the earliest biblical manuscript still in existence. Along with biblical texts, the scrolls include documents about sectarian regulations and religious writings that do not appear in the Old Testament.

The writing on the Dead Sea Scrolls is mostly in black or occasionally red ink, and the scrolls themselves are nearly all made of either parchment (animal skin) or an early form of paper called ‘papyrus’. The only exception is the scroll numbered 3Q15, which was created out of a combination of copper and tin. Known as the Copper Scroll, this curious document features letters chiselled onto metal – perhaps, as some have theorized, to better withstand the passage of time. One of the most intriguing manuscripts from Qumran, this is a sort of ancient treasure map that lists dozens of gold and silver caches. Using an unconventional vocabulary and odd spelling, it describes 64 underground hiding places that supposedly contain riches buried for safekeeping. None of these hoards have been recovered, possibly because the Romans pillaged Judea during the first century CE. According to various hypotheses, the treasure belonged to local people, or was rescued from the Second Temple before its destruction or never existed to begin with.

Some of the Dead Sea Scrolls have been on interesting journeys. In 1948, a Syrian Orthodox archbishop known as Mar Samuel acquired four of the original seven scrolls from a Jerusalem shoemaker and part-time antiquity dealer, paying less than $100 for them. He then travelled to the United States and unsuccessfully offered them to a number of universities, including Yale. Finally, in 1954, he placed an advertisement in the business newspaper The Wall Street Journal – under the category ‘Miscellaneous Items for Sale’ – that read: ‘Biblical Manuscripts dating back to at least 200 B.C. are for sale. This would be an ideal gift to an educational or religious institution by an individual or group.’ Fortunately, Israeli archaeologist and statesman Yigael Yadin negotiated their purchase and brought the scrolls back to Jerusalem, where they remain to this day.

In 2017, researchers from the University of Haifa restored and deciphered one of the last untranslated scrolls. The university’s Eshbal Ratson and Jonathan Ben-Dov spent one year reassembling the 60 fragments that make up the scroll. Deciphered from a band of coded text on parchment, the find provides insight into the community of people who wrote it and the 364-day calendar they would have used. The scroll names celebrations that indicate shifts in seasons and details two yearly religious events known from another Dead Sea Scroll. Only one more known scroll remains untranslated.

Questions 1–5

Complete the notes below. Choose ONE WORD ONLY from the passage for each answer. Write your answers in boxes 1–5.

The Dead Sea Scrolls

Discovery
Qumran, 1946/7

  • three Bedouin shepherds in their teens were near an opening on side of cliff
  • heard a noise of breaking when one teenager threw a 1...................
  • teenagers went into the 2..................  and found a number of containers made of 3.................. 

The scrolls

  • date from between 150 BCE and 70 CE
  • thought to have been written by group of people known as the 4......................
  • written mainly in the 5......................  language
  • most are on religious topics, written using ink on parchment or papyrus

Questions 6–13

Do the following statements agree with the information given in Reading Passage 1? In boxes 6–13 on your answer sheeet, write:
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

6. The Bedouin teenagers who found the scrolls were disappointed by how little money they received for them.

7. There is agreement among academics about the origin of the Dead Sea Scrolls..

8. Most of the books of the Bible written on the scrolls are incomplete.

9. The information on the Copper Scroll is written in an unusual way.

10. Mar Samuel was given some of the scrolls as a gift.

11. In the early 1950s, a number of educational establishments in the US were keen to buy scrolls from Mar Samuel.

12. The scroll that was pieced together in 2017 contains information about annual occasions in the Qumran area 2,000 years ago.
13. Academics at the University of Haifa are currently researching how to decipher the final scroll.

56. Bài 56

A second attempt at domesticating the tomato

A. It took at least 3,000 years for humans to learn how to domesticate the wild tomato and cultivate it for food. Now two separate teams in Brazil and China have done it all over again in less than three years. And they have done it better in some ways, as the re-domesticated tomatoes are more nutritious than the ones we eat at present.

This approach relies on the revolutionary CRISPR genome editing technique, in which changes are deliberately made to the DNA of a living cell, allowing genetic material to be added, removed or altered. The technique could not only improve existing crops, but could also be used to turn thousands of wild plants into useful and appealing foods. In fact, a third team in the US has already begun to do this with a relative of the tomato called the groundcherry.

This fast-track domestication could help make the world’s food supply healthier and far more resistant to diseases, such as the rust fungus devastating wheat crops.

‘This could transform what we eat,’ says Jorg Kudla at the University of Munster in Germany, a member of the Brazilian team. ‘There are 50,000 edible plants in the world, but 90 percent of our energy comes from just 15 crops.’

‘We can now mimic the known domestication course of major crops like rice, maize, sorghum or others,’ says Caixia Gao of the Chinese Academy of Sciences in Beijing. ‘Then we might try to domesticate plants that have never been domesticated.’

B. Wild tomatoes, which are native to the Andes region in South America, produce pea-sized fruits. Over many generations, peoples such as the Aztecs and Incas transformed the plant by selecting and breeding plants with mutations* in their genetic structure, which resulted in desirable traits such as larger fruit.

But every time a single plant with a mutation is taken from a larger population for breeding, much genetic diversity is lost. And sometimes the desirable mutations come with less desirable traits. For instance, the tomato strains grown for supermarkets have lost much of their flavour.

By comparing the genomes of modern plants to those of their wild relatives, biologists have been working out what genetic changes occurred as plants were domesticated. The teams in Brazil and China have now used this knowledge to reintroduce these changes from scratch while maintaining or even enhancing the desirable traits of wild strains.

C. Kudla’s team made six changes altogether. For instance, they tripled the size of fruit by editing a gene called FRUIT WEIGHT, and increased the number of tomatoes per truss by editing another called MULTIFLORA.

While the historical domestication of tomatoes reduced levels of the red pigment lycopene – thought to have potential health benefits – the team in Brazil managed to boost it instead. The wild tomato has twice as much lycopene as cultivated ones; the newly domesticated one has five times as much.

‘They are quite tasty,’ says Kudla. ‘A little bit strong. And very aromatic.’

The team in China re-domesticated several strains of wild tomatoes with desirable traits lost in domesticated tomatoes. In this way they managed to create a strain resistant to a common disease called bacterial spot race, which can devastate yields. They also created another strain that is more salt tolerant – and has higher levels of vitamin C.

D. Meanwhile, Joyce Van Eck at the Boyce Thompson Institute in New York state decided to use the same approach to domesticate the groundcherry or goldenberry (Physalis pruinosa) for the first time. This fruit looks similar to the closely related Cape gooseberry (Physalis peruviana).

Groundcherries are already sold to a limited extent in the US but they are hard to produce because the plant has a sprawling growth habit and the small fruits fall off the branches when ripe. Van Eck’s team has edited the plants to increase fruit size, make their growth more compact and to stop fruits dropping. ‘There’s potential for this to be a commercial crop,’ says Van Eck. But she adds that taking the work further would be expensive because of the need to pay for a licence for the CRISPR technology and get regulatory approval.

E. This approach could boost the use of many obscure plants, says Jonathan Jones of the Sainsbury Lab in the UK. But it will be hard for new foods to grow so popular with farmers and consumers that they become new staple crops, he thinks.

The three teams already have their eye on other plants that could be ‘catapulted into the mainstream’, including foxtail, oat-grass and cowpea. By choosing wild plants that are drought or heat tolerant, says Gao, we could create crops that will thrive even as the planet warms.

But Kudla didn’t want to reveal which species were in his team’s sights, because CRISPR has made the process so easy. ‘Any one with the right skills could go to their lab and do this.’

* mutations: changes in an organism’s genetic structure that can be passed down to later generations

Questions 14–18

Reading Passage 2 has five sections, A–E.
Which section contains the following information?
Write the correct letter, A–E, in boxes 14–18 on your answer sheet.
NB You may use any letter more than once.

14. a reference to a type of tomato that can resist a dangerous infection

15. an explanation of how problems can arise from focusing only on a certain type of tomato plant.

16. a number of examples of plants that are not cultivated at present but could be useful as food sources

17. a comparison between the early domestication of the tomato and more recent research

18. a personal reaction to the flavour of a tomato that has been genetically edited
Questions 19–23

Look at the following statements (Questions 19–23) and the list of researchers below. Match each statement with the correct researcher, A–D. Write the correct letter, A–D, in boxes 19–23 on your answer sheet.
NB You may use any letter more than once.

List of Researchers
A. Jorg Kudla
B. Caixia Gao
C. Joyce Van Eck
D. Jonathan Jones

19. Domestication of certain plants could allow them to adapt to future environmental challenges.
20. The idea of growing and eating unusual plants may not be accepted on a large scale.
21. It is not advisable for the future direction of certain research to be made public.
22. Present efforts to domesticate one wild fruit are limited by the costs involved.
23. Humans only make use of a small proportion of the plant food available on Earth.
Questions 24–26

Complete the sentences below. Choose ONE WORD ONLY from the passage for each answer. Write your answers in boxes 24-26 on your answer sheet.
24. An undesirable trait such as loss of ..................... may be caused by a mutation in a tomato gene.
25. By modifying one gene in a tomato plant, researchers made the tomato three times its original .....................
26. A type of tomato which was not badly affected by ...................., and was rich in vitamin C, was produced by a team of researchers in China.

57. Bài 57

The thylacine

The extinct thylacine, also known as the Tasmanian tiger, was a marsupial* that bore a superficial resemblance to a dog. Its most distinguishing feature was the 13-19 dark brown stripes over its back, beginning at the rear of the body and extending onto the tail. The thylacine’s average nose-to-tail length for adult males was 162.6 cm, compared to 153.7 cm for females.

The thylacine appeared to occupy most types of terrain except dense rainforest, with open eucalyptus forest thought to be its prime habitat. In terms of feeding, it was exclusively carnivorous, and its stomach was muscular with an ability to distend so that it could eat large amounts of food at one time, probably an adaptation to compensate for long periods when hunting was unsuccessful and food scarce. The thylacine was not a fast runner and probably caught its prey by exhausting it during a long pursuit. During long-distance chases, thylacines were likely to have relied more on scent than any other sense. They emerged to hunt during the evening, night and early morning and tended to retreat to the hills and forest for shelter during the day. Despite the common name ‘tiger’, the thylacine had a shy, nervous temperament. Although mainly nocturnal, it was sighted moving during the day and some individuals were even recorded basking in the sun.

The thylacine had an extended breeding season from winter to spring, with indications that some breeding took place throughout the year. The thylacine, like all marsupials, was tiny and hairless when born. Newborns crawled into the pouch on the belly of their mother, and attached themselves to one of the four teats, remaining there for up to three months. When old enough to leave the pouch, the young stayed in a lair such as a deep rocky cave, well-hidden nest or hollow log, whilst the mother hunted.

Approximately 4,000 years ago, the thylacine was widespread throughout New Guinea and most of mainland Australia, as well as the island of Tasmania. The most recent, well-dated occurrence of a thylacine on the mainland is a carbon-dated fossil from Murray Cave in Western Australia, which is around 3,100 years old. Its extinction coincided closely with the arrival of wild dogs called dingoes in Australia and a similar predator in New Guinea. Dingoes never reached Tasmania, and most scientists see this as the main reason for the thylacine’s survival there.

The dramatic decline of the thylacine in Tasmania, which began in the 1830s and continued for a century, is generally attributed to the relentless efforts of sheep farmers and bounty hunters** with shotguns. While this determined campaign undoubtedly played a large part, it is likely that various other factors also contributed to the decline and eventual extinction of the species. These include competition with wild dogs introduced by European settlers, loss of habitat along with the disappearance of prey species, and a distemper-like disease which may also have affected the thylacine.

There was only one successful attempt to breed a thylacine in captivity, at Melbourne Zoo in 1899. This was despite the large numbers that went through some zoos, particularly London Zoo and Tasmania’s Hobart Zoo. The famous naturalist John Gould foresaw the thylacine’s demise when he published his Mammals of Australia between 1848 and 1863, writing, ‘The numbers of this singular animal will speedily diminish, extermination will have its full sway, and it will then, like the wolf of England and Scotland, be recorded as an animal of the past.’

However, there seems to have been little public pressure to preserve the thylacine, nor was much concern expressed by scientists at the decline of this species in the decades that followed. A notable exception was T.T. Flynn, Professor of Biology at the University of Tasmania. In 1914, he was sufficiently concerned about the scarcity of the thylacine to suggest that some should be captured and placed on a small island. But it was not until 1929, with the species on the very edge of extinction, that Tasmania’s Animals and Birds Protection Board passed a motion protecting thylacines only for the month of December, which was thought to be their prime breeding season. The last known wild thylacine to be killed was shot by a farmer in the north-east of Tasmania in 1930, leaving just captive specimens. Official protection of the species by the Tasmanian government was introduced in July 1936, 59 days before the last known individual died in Hobart Zoo on 7th September, 1936.

There have been numerous expeditions and searches for the thylacine over the years, none of which has produced definitive evidence that thylacines still exist. The species was declared extinct by the Tasmanian government in 1986.

* marsupial: a mammal, such as a kangaroo, whose young are born incompletely developed and are typically carried and suckled in a pouch on the mother’s belly

**bounty hunters: people who are paid a reward for killing a wild animal

Questions 1-5
Complete the notes below. Choose ONE WORD ONLY from the passage for each answer. Write your answers in boxes 1-5 on your answer sheet.

The thylacine

Appearance and behaviour

  • looked rather like a dog
  • had a series of stripes along its body and tail
  • ate an entirely 1 ………………… diet
  • probably depended mainly on 2 ………………… when hunting
  • young spent first months of life inside its mother’s 3 …………………

Decline and extinction

  • last evidence in mainland Australia is a 3,100-year-old 4 …………………
  • probably went extinct in mainland Australia due to animals known as dingoes
  • reduction in 5 ………………… and available sources of food were partly responsible for decline in Tasmania

Questions 6-13
Do the following statements agree with the information given in Reading Passage 1? In boxes 6-13 on your answer sheet, write:

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this
6. Significant numbers of thylacines were killed by humans from the 1830s onwards.

7. Several thylacines were born in zoos during the late 1800s.

8. John Gould’s prediction about the thylacine surprised some biologists.

9. In the early 1900s, many scientists became worried about the possible extinction of the thylacine.

10. T.T. Flynn’s proposal to rehome captive thylacines on an island proved to be impractical.

11. There were still reasonable numbers of thylacines in existence when a piece of legislation protecting the species during their breeding season was passed.

12. From 1930 to 1936, the only known living thylacines were all in captivity.

13. Attempts to find living thylacines are now rarely made.

58. Bài 58

Palm oil

A. Palm oil is an edible oil derived from the fruit of the African oil palm tree, and is currently the most consumed vegetable oil in the world. It’s almost certainly in the soap we wash with in the morning, the sandwich we have for lunch, and the biscuits we snack on during the day. Why is palm oil so attractive for manufacturers? Primarily because its unique properties – such as remaining solid at room temperature – make it an ideal ingredient for long-term preservation, allowing many packaged foods on supermarket shelves to have ‘best before’ dates of months, even years, into the future.

B. Many farmers have seized the opportunity to maximise the planting of oil palm trees. Between 1990 and 2012, the global land area devoted to growing oil palm trees grew from 6 to 17 million hectares, now accounting for around ten percent of total cropland in the entire world. From a mere two million tonnes of palm oil being produced annually globally 50 years ago, there are now around 60 million tonnes produced every single year, a figure looking likely to double or even triple by the middle of the century.

C. However, there are multiple reasons why conservationists cite the rapid spread of oil palm plantations as a major concern. There are countless news stories of deforestation, habitat destruction and dwindling species populations, all as a direct result of land clearing to establish oil palm tree monoculture on an industrial scale, particularly in Malaysia and Indonesia. Endangered species – most famously the Sumatran orangutan, but also rhinos, elephants, tigers, and numerous other fauna – have suffered from the unstoppable spread of oil palm plantations.

D. ‘Palm oil is surely one of the greatest threats to global biodiversity,’ declares Dr Farnon Ellwood of the University of the West of England, Bristol. ‘Palm oil is replacing rainforest, and rainforest is where all the species are. That’s a problem.’ This has led to some radical questions among environmentalists, such as whether consumers should try to boycott palm oil entirely.

Meanwhile Bhavani Shankar, Professor at London’s School of Oriental and African Studies, argues, ‘It’s easy to say that palm oil is the enemy and we should be against it. It makes for a more dramatic story, and it’s very intuitive. But given the complexity of the argument, I think a much more nuanced story is closer to the truth.’

E. One response to the boycott movement has been the argument for the vital role palm oil plays in lifting many millions of people in the developing world out of poverty. Is it desirable to have palm oil boycotted, replaced, eliminated from the global supply chain, given how many low-income people in developing countries depend on it for their livelihoods? How best to strike a utilitarian balance between these competing factors has become a serious bone of contention.

F. Even the deforestation argument isn’t as straightforward as it seems. Oil palm plantations produce at least four and potentially up to ten times more oil per hectare than soybean, rapeseed, sunflower or other competing oils. That immensely high yield – which is predominantly what makes it so profitable – is potentially also an ecological benefit. If ten times more palm oil can be produced from a patch of land than any competing oil, then ten times more land would need to be cleared in order to produce the same volume of oil from that competitor.

As for the question of carbon emissions, the issue really depends on what oil palm trees are replacing. Crops vary in the degree to which they sequester carbon – in other words, the amount of carbon they capture from the atmosphere and store within the plant. The more carbon a plant sequesters, the more it reduces the effect of climate change. As Shankar explains: ‘[Palm oil production] actually sequesters more carbon in some ways than other alternatives. […] Of course, if you’re cutting down virgin forest it’s terrible – that’s what’s happening in Indonesia and Malaysia, it’s been allowed to get out of hand. But if it’s replacing rice, for example, it might actually sequester more carbon.’

G. The industry is now regulated by a group called the Roundtable on Sustainable Palm Oil (RSPO), consisting of palm growers, retailers, product manufacturers, and other interested parties. Over the past decade or so, an agreement has gradually been reached regarding standards that producers of palm oil have to meet in order for their product to be regarded as officially ‘sustainable’. The RSPO insists upon no virgin forest clearing, transparency and regular assessment of carbon stocks, among other criteria. Only once these requirements are fully satisfied is the oil allowed to be sold as certified sustainable palm oil (CSPO). Recent figures show that the RSPO now certifies around 12 million tonnes of palm oil annually, equivalent to roughly 21 percent of the world’s total palm oil production.

H. There is even hope that oil palm plantations might not need to be such sterile monocultures, or ‘green deserts’, as Ellwood describes them. New research at Ellwood’s lab hint at one plant which might make all the difference. The bird’s nest fern (Asplenium nidus) grows on trees in an epiphytic fashion (meaning it’s dependent on the tree only for support, not for nutrients), and is native to many tropical regions, where as a keystone species it performs a vital ecological role. Ellwood believes that reintroducing the bird’s nest fern into oil palm plantations could potentially allow these areas to recover their biodiversity, providing a home for all manner of species, from fungi and bacteria, to invertebrates such as insects, amphibians, reptiles and even mammals.

Questions 14-20
Reading Passage 2 has eight paragraphs, A-H.

Which section contains the following information?

Write the correct letter, A-H, in boxes 14-20 on your answer sheet.
14. examples of a range of potential environmental advantages of oil palm tree cultivation

15. description of an organisation which controls the environmental impact of palm oil production

16. examples of the widespread global use of palm oil

17. reference to a particular species which could benefit the ecosystem of oil palm plantations

18. figures illustrating the rapid expansion of the palm oil industry

19. an economic justification for not opposing the palm oil industry

20. examples of creatures badly affected by the establishment of oil palm plantations

Questions 21 and 22
Choose TWO letters, A-E. Write the correct letters in boxes 21 and 22 on your answer sheet.

Which TWO statements are made about the Roundtable on Sustainable Palm Oil (RSPO)?

A. Its membership has grown steadily over the course of the last decade.
B. It demands that certified producers be open and honest about their practices.

C. It took several years to establish its set of criteria for sustainable palm oil certification.

D. Its regulations regarding sustainability are stricter than those governing other industries.

E. It was formed at the request of environmentalists concerned about the loss of virgin forests.

Questions 23-26
Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 23-26 on your answer sheet.
23. One advantage of palm oil for manufacturers is that it stays ……………………… even when not refrigerated.

24. The ………… is the best known of the animals suffering habitat loss as a result of the spread of oil palm plantations.

25. As one of its criteria for the certification of sustainable palm oil, the RSPO insists that growers check ………… on a routine basis.

26. Ellwood and his researchers are looking into whether the bird’s nest fern could restore ………………… in areas where oil palm trees are grown.

59. Bài 59

Bats to the rescue

How Madagascar’s bats are helping to save the rainforest

There are few places in the world where relations between agriculture and conservation are more strained. Madagascar’s forests are being converted to agricultural land at a rate of one percent every year. Much of this destruction is fuelled by the cultivation of the country’s main staple crop: rice. And a key reason for this destruction is that insect pests are destroying vast quantities of what is grown by local subsistence farmers, leading them to clear forest to create new paddy fields. The result is devastating habitat and biodiversity loss on the island, but not all species are suffering. In fact, some of the island’s insectivorous bats are currently thriving and this has important implications for farmers and conservationists alike.

Enter University of Cambridge zoologist Ricardo Rocha. He’s passionate about conservation, and bats. More specifically, he’s interested in how bats are responding to human activity and deforestation in particular. Rocha’s new study shows that several species of bats are giving Madagascar’s rice farmers a vital pest control service by feasting on plagues of insects. And this, he believes, can ease the financial pressure on farmers to turn forest into fields.

Bats comprise roughly one-fifth of all mammal species in Madagascar and thirty-six recorded bat species are native to the island, making it one of the most important regions for conservation of this animal group anywhere in the world.

Co-leading an international team of scientists, Rocha found that several species of indigenous bats are taking advantage of habitat modification to hunt insects swarming above the country’s rice fields. They include the Malagasy mouse-eared bat, Major’s long-fingered bat, the Malagasy white-bellied free-tailed bat and Peters’ wrinkle-lipped bat.

‘These winner species are providing a valuable free service to Madagascar as biological pest suppressors,’ says Rocha. ‘We found that six species of bat are preying on rice pests, including the paddy swarming caterpillar and grass webworm. The damage which these insects cause puts the island’s farmers under huge financial pressure and that encourages deforestation.’

The study, now published in the journal Agriculture, Ecosystems and Environment, set out to investigate the feeding activity of insectivorous bats in the farmland bordering the Ranomafana National Park in the southeast of the country.

Rocha and his team used state-of-the-art ultrasonic recorders to record over a thousand bat ‘feeling buzzes’ (echolocation sequences used by bats to target their prey) at 54 sites, in order to identify the favourite feeding spots of the bats. The next used DNA barcoding techniques to analyse droppings collected from bats at the different sites.

The recordings revealed that bat activity over rice fields was much higher than it was in continuous forest – seven times higher over rice fields which were on flat ground, and sixteen times higher over fields on the sides of hills – leaving no doubt that the animals are preferentially foraging in these man-made ecosystems. The researchers suggest that the bats favour these fields because lack of water and nutrient run-off make these crops more susceptible to insect pest infestations. DNA analysis showed that all six species of bat had fed on economically important insect pests. While the findings indicated that rice farming benefits most from the bats, the scientists also found indications that the bats were consuming pests of other crops, including the black twig borer (which infests coffee plants), the sugarcane cicada, the macadamia nut-borer, and the sober tabby (a pest of citrus fruits).

‘The effectiveness of bats as pest controllers has already been proven in the USA and Catalonia,’ said co-author James Kemp, from the University of Lisbon. ‘But our study is the first to show this happening in Madagascar, where the stakes for both farmers and conservationists are so high.’

Local people may have a further reason to be grateful to their bats. While the animal is often associated with spreading disease, Rocha and his team found evidence that Malagasy bats feed not just on crop pests but also on mosquitoes – carriers of malaria, Rift Valley fever virus and elephantiasis – as well as blackflies, which spread river blindness.

Rocha points out that the relationship is complicated. When food is scarce, bats become a crucial source of protein for local people. Even the children will hunt them. And as well as roosting in trees, the bats sometimes roost in buildings, but are not welcomed there because they make them unclean. At the same time, however, they are associated with sacred caves and the ancestors, so they can be viewed as beings between worlds, which makes them very significant in the culture of the people. And one potential problem is that while these bats are benefiting from farming, at the same time deforestation is reducing the places where they can roost, which could have long-term effects on their numbers. Rocha says, ‘With the right help, we hope that farmers can promote this mutually beneficial relationship by installing bat houses.’
Rocha and his colleagues believe that maximising bat populations can help to boost crop yields and promote sustainable livelihoods. The team is now calling for further research to quantify this contribution. ‘I’m very optimistic,’ says Rocha. ‘If we give nature a hand, we can speed up the process of regeneration.’

 

Questions 1-6
Do the following statements agree with the information given in Reading Passage 1? In boxes 1-6 on your answer sheet, write:

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this
1. Many Madagascan forests are being destroyed by attacks from insects.

2. Loss of habitat has badly affected insectivorous bats in Madagascar.

3. Ricardo Rocha has carried out studies of bats in different parts of the world.

4. Habitat modification has resulted in indigenous bats in Madagascar becoming useful to farmers.

5. The Malagasy mouse-eared bat is more common than other indigenous bat species in Madagascar.

6. Bats may feed on paddy swarming caterpillars and grass webworms.

Questions 7-13
Complete the table below. Choose ONE WORD ONLY from the passage for each answer. Write your answers in boxes 7-13 on your answer sheet.

Bats to the rescue

60. Bài 60

Secrets of the swarm

Insects, birds and fish tend to be the creatures that humans feel furthest from. Unlike many mammals they do not engage in human-like behaviour. The way they swarm or flock together does not usually get good press coverage either: marching like worker ants might be a common simile for city commuters, but it’s a damning, not positive, image. Yet a new school of scientific theory suggests that these swarms might have a lot to teach us.
American author Peter Miller explains, ‘I used to think that individual ants knew where they were going, and what they were supposed to do when they got there. But Deborah Gordon, a biologist at Stanford University, showed me that nothing an ant does makes any sense except in terms of the whole colony. Which makes you wonder if, as individuals, we don’t serve a similar function for the companies where we work or the communities where we live.’ Ants are not intelligent by themselves. Yet as a colony, they make wise decisions. And as Gordon discovered during her research, there’s no one ant making decisions or giving orders.
Take food collecting, for example. No ant decides, ‘There’s lots of food around today; lots of ants should go out to collect it.’ Instead, some forager ants go out, and as soon as they find food, they pick it up and come back to the nest. At the entrance, they brush past reserve foragers, sending a ‘go out’ signal. The faster the foragers come back, the more food there is and the faster other foragers go out, until gradually the amount of food being brought back diminishes. An organic calculation has been made to answer the question, ‘How many foragers does the colony need today?’ And if something goes wrong – a hungry lizard prowling around for an ant snack, for instance – then a rush of ants returning without food sends waiting reserves a ‘Don’t go out’ signal.
But could such decentralised control work in a human organisation? Miller visited a Texas gas company that has successfully applied formulas based on ant colony behaviour to ‘optimise its factories and route its trucks’. He explains, ‘If ant colonies had worked out a reliable way to identify the best routes between their nest and food sources, the company managers figured, why not take advantage of that knowledge?’ So they came up with a computer model, based on the self-organising principles of an ant colony. Data is fed into the model about deliveries needing to be made the next day, as well as things like weather conditions, and it produces a simulation determining the best route for the delivery lorries to take.
Miller explains that he first really understood the impact that swarm behaviour could have on humans when he read a study of honeybees by Tom Seeley, a biologist at Cornell University. The honeybees choose as a group which new nest to move to. First, scouts fly off to investigate multiple sites. When they return they do a ‘waggle dance’ for their spot, and other scouts will then fly off and investigate it. Many bees go out, but none tries to compare all sites. Each reports back on just one. The more they liked their nest, the more vigorous and lengthy their waggle dance and the more bees will choose to visit it. Gradually the volume of bees builds up towards one site; it’s a system that ensures that support for the
best site snowballs and the decision is made in the most democratic way.
Humans, too, can make clever decisions through diversity of knowledge and a little friendly competition. ‘The best example of shared decisionmaking that I witnessed during my research was a town meeting I attended in Vermont, where citizens met face-to-face to debate their annual budget,’ explains Miller. ‘For group decision-making to work well, you need a way to sort through the various options they propose; and you need a mechanism to narrow down these options.’ Citizens in Vermont control their municipal affairs by putting forward proposals, or backing up others’ suggestions, until a consensus is reached through a vote. As with the bees, the broad sampling of options before a decision is made will usually result in a compromise acceptable to all. The ‘wisdom of the crowd’ makes clever decisions for the good of the group – and leaves citizens feeling represented and respected.
The Internet is also an area where we are increasingly exhibiting swarm behaviour, without any physical contact. Miller compares a wiki website, for example, to a termite mound. Indirect collaboration is the key principle behind information-sharing web sites, just as it underlies the complex constructions that termites build. Termites do not have an architect’s blueprint or a grand construction scheme. They simply sense changes in their environment, as for example when the mound’s wall has been damaged, altering the circulation of air. They go to the site of the change and drop a grain of soil. When the next termite finds that grain, they drop theirs too. Slowly, without any kind of direct decision-making, a new wall is built. A termite mound, in this way, is rather like a wiki website. Rather than meeting up and talking about what we want to post online, we just add to what someone – maybe a stranger on the other side of the world – already wrote. This indirect knowledge and skill-sharing is now finding its way into the corridors of power.

Questions 1-6
Do the following statements agree with the information in the text? In boxes 1-6 on your answer sheet, write:
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

1. Commuters are often compared favourably with worker ants.
2. Some ants within a colony have leadership roles.
3. Forager ants tell each other how far away the food source is.
4. Forager ants are able to react quickly to a dangerous situation.
5. Termite mounds can be damaged by the wind.
6. Termites repair their mounds without directly communicating with each other.
Questions 7-9
Complete each sentence with the correct ending, A-F, below. Write the correct letter, A-F, in boxes 7-9 on your answer sheet.
7. Managers working for a Texas gas company
8. Citizens in an annual Vermont meeting
9. Some Internet users
A. provide support for each other’s ideas in order to reach the best outcome.
B. use detailed comments to create large and complicated systems.
C. use decision-making strategies based on insect communities to improve their service.
D. communicate with each other to decide who the leader will be.
E. contribute independently to the ideas of others they do not know.
F. repair structures they have built without directly communicating with each other

Questions 10-13

Complete the flow-chart below. Choose NO MORE THAN TWO WORDS from the text for each answer. Write your answers in boxes 10-13 on your answer sheet.

Secrets of the swarm

61. Bài 61

The Rise Of Agribots

The use of robots and automation in the farming industry.

The next time you stand at the supermarket checkout, spare a thought for the farmers who helped fill your shopping basket as life is hard for them right now. This, in turn, inevitably means bigger grocery bills for consumers, and greater hardship for the millions in countries where food shortages are a matter of life and death. Worse, studies suggest that the world will need twice as much food by 2050. Yet while farmers must squeeze more out of the land, they must also address the necessity of reducing their impact on the soil, waterways and atmosphere. All this means rethinking how agriculture is practiced, and taking automation to a whole new level. On the new model farms of the future, precision will be key. Why dose a whole field with chemicals if you can spray only where they are needed? Each plant could get exactly the right amount of everything, no more or less, an approach that could slash chemical use and improve yields in one move. But this is easier said than done; the largest farms in Europe and the U.S. can cover thousands of acres. That’s why automation is key to precision farming. Specifically, say agricultural engineers, precision farming needs robot farmers.

One day, we might see fields with ‘agribots’ (agricultural robots) that can identify individual seedlings and encourage them along with drops of fertiliser. Other machines would distinguish problem weeds from crops and eliminate them with shots from high-power lasers or a microdot of pesticide. These machines will also be able to identify and harvest all kinds of vegetables. More than a century of mechanization has already turned farming into an industrial-scale activity in much of the world, with farms that grow cereals being the most heavily automated. But a variety of other crops, including oranges and tomatoes destined to become processed foods, are also picked mechanically, albeit to a slightly lesser extent. Yet the next wave of autonomous farm machinery is already at work. You probably haven’t even noticed, for these robots are disguised as tractors. Many are self-steering, use GPS to cross a field, and can even ‘talk’ to their implements – a plough or sprayer, for example. And the implements can talk back, telling the tractor that it’s going too fast or needs to move to the left. This kind of communication is also being developed in other farm vehicles. A new system allows a combine harvester, say, to send a call over to a tractor- trailer so the driver can unload the grain as and when necessary.

However, when fully autonomous systems take to the field, they’ll look nothing like tractors. With their enormous size and weight, today’s farm machines have significant downsides: they compact the soil, reducing porosity and killing beneficial life, meaning crops don’t grow so well. Simon Blackmore, who researches agricultural technology at Harper Adams University College in England believes that fleets of lightweight autonomous robots have the potential to solve this problem and that replacing brute force with precision is key. ‘A seed only needs one cubic centimeter of soil to grow. If we cultivate just that we only put tiny amounts of energy in and the plants still grow nicely.’ There is another reason why automation may be the way forward according to Eldert van Henten, a robotics researcher at Wageningen University in the Netherlands. ‘While the population is growing and needs to be fed, a rapidly shrinking number of people are willing to work in agriculture,’ he points out.

Other researchers such as Linda Calvin, an economist at the U.S. Department of Agriculture, and Philip Martin at the University of California, Davis, have studied trends in mechanization to predict how US farms might fare. Calvin and Martin have observed how rising employment costs have led to the adoption of labour-saving farm technology in the past, citing the raisin industry as an example. In 2000, a bumper harvest crashed prices and, with profits squeezed, farmers looked for a solution. With labour one of their biggest costs – 42 percent of production expenses on U.S. farms, on average – they started using a mechanical harvester adapted from a machine used by wine makers. By 2007, almost half of California’s raisins were mechanically harvested and a labour force once numbering 50,000 had shrunk to 30,000.

As well as having an impact on the job market, the widespread adoption of agribots might bring changes at the supermarket. Lewis Holloway, who studies agriculture at the University of Hull, UK, says that robotic milking is likely to influence the genetics of dairy herds as farmers opt for ‘robot-friendly‘ cows, with udder shape, and even attitudes, suited to automated milking. Similarly, he says, it’s conceivable that agribots could influence what fruit or vegetable varieties get to the shops, since farmers may prefer to grow those with, say, leaf shapes that are easier for their robots to discriminate from weeds. Almost inevitably, these machines will eventually alter the landscape, too. The real tipping point for robot agriculture will come when farms are being designed with agribots in mind, says Salah Sukkarieh, a robotics researcher at the Australian Center for Field Robotics, Sydney. This could mean a return to smaller fields, with crops planted in grids rather than rows and fruit trees pruned into two- dimensional shapes to make harvesting easier. This alien terrain tended by robots is still a while away, he says ‘but it will happen‘.

Question 14-17
Do the following statements agree with the information given in the Reading Passage? In boxes 14-17 on your answer sheet, write:
YES if the statement agrees with the information
NO if the statement contradicts the information
NOT GIVEN if it is impossible to say what the writer thinks about this

14. Governments should do more to ensure that food is generally affordable.
15. Farmers need to reduce the harm they do to the environment.
16. In the future, farmers are likely to increase their dependency on chemicals.
17. Farms in Europe and the US may find it hard to adapt to precision farming.

Question 18 - 21
Complete the sentences below. Choose ONE WORD ONLY from the passage for each answer. Write your answers in boxes 18-21 on your answer sheet.
5. In the future, agribots will provide ................. to young plants.
6. Some machines will use chemicals or ................... to get rid of unwanted plants.
7. It is the production of ................. which currently uses most machinery on farms.
8. .................. between machines such as tractors is making farming more efficient.

Question 22 - 26
Look at the following researchers (Questions 22-26) and the list of statements below. Match each researcher with the correct statement, A-H. Write the correct letter, A-H, in boxes 22-26 on your answer sheet.

22. Simon Blackmore
23. Eldert van Henten
24. Linda Calvin and Philip Martin
25. Lewis Holloway
26. Salah Sukkarieh
List of Findings
A. The use of automation might impact on the development of particular animal and plant species.
B. We need to consider the effect on employment that increased automation will have.
C. We need machines of the future to be exact, not more powerful.
D. As farming becomes more automated the appearance of farmland will change.
E. New machinery may require more investment than certain farmers can afford.
F. There is a shortage of employees in the farming industry.
G. There are limits to the environmental benefits of automation.
H. Economic factors are often the driving force behind the development of machinery.

62. Bài 62

Questions 1-7
Reading Passage 1 has seven paragraphs, A-G. Choose the correct heading for each paragraph from the list of headings below. Write the correct number, i-x, in boxes 1-7 on your answer sheet.
List of Headings
i. How deforestation harms isolated trees
ii. How other plants can cause harm
iii. Which big trees support the most diverse species
iv. Impact of big tree loss on the wider environment
v. Measures to prevent further decline in big tree populations
vi. How wildlife benefits from big trees
vii. Risk from pests and infection
viii. Ways in which industry uses big tree products
ix. How higher temperatures slow the rate of tree growth
x. Factors that enable trees to grow to significant heights
1. Paragraph A
2. Paragraph B
3. Paragraph C
4. Paragraph D
5. Paragraph E
6. Paragraph F
7. Paragraph G

Trees in Trouble

What is causing the decline of the world's gian forests?

A. Big trees are incredibly important ecologically. For a start, they sustain countless other species. They provide shelter for many animals, and their trunks and branches can become gardens, hung with green ferns, orchids and bromeliads, coated with mosses and draped with vines. With their tall canopies* basking in the sun, they capture vast amounts of energy. This allows them to produce massive crops of fruit, flowers and foliage that sustain much of the animal life in the forest.

B. Only a small number of tree species have the genetic capacity to grow really big. The mightiest are native to North America, but big trees grow all over the globe, from the tropics to the boreal forests of the high latitudes. To achieve giant stature, a tree needs three things: the right place to establish its seedling, good growing conditions and lots of time with low adult mortality*. Disrupt any of these, and you can lose your biggest trees.

C. In some parts of the world, populations of big trees are dwindling because their seedlings cannot survive or grow. In southern India, for instance, an aggressive non-native shrub, Lantana camara, is invading the floor of many forests. Lantana grows so thickly that young trees often fail to take root. With no young trees to replace them, it is only a matter of time before most of the big trees disappear. Across much of northern Australia, gamba grass from Africa is overrunning native savannah woodlands. The grass grows up to four metres tall and burns fiercely, creating super-hot fires that cause catastrophic tree mortality.

D. Without the right growing conditions trees cannot get really big, and there is some evidence to suggest tree growth could slow in a warmer world, particularly in environments that are already warm. Having worked for decades at La Selva Biological Station in Puerto Viejo de Sarapiqui, Costa Rica, David and Deborah Clark and colleagues have shown that tree growth there declines markedly in warmer years. “During the day, their photosynthesis* shuts down when it gets too warm, and at night they consume more energy because their metabolic rate increases, much as a reptile’s would when it gets warmer,” explains David Clark. With less energy produced in warmer years and more being consumed just to survive, there is even less energy available for growth.

E. The Clarks’ hypothesis, if correct, means tropical forests would shrink over time. The largest, oldest trees would progressively die off and tend not to be replaced. According to the Clarks, this might trigger a destabilisation of the climate; as older trees die, forests would release some of their stored carbon into the atmosphere, prompting a vicious cycle of further warming, forest shrinkage and carbon emissions.

F. Big trees face threats from elsewhere. The most serious is increasing mortality, especially of mature trees. Across much of the planet, forests of slow-growing ancient trees have been cleared for human use. In western North America, most have been replaced by monocultures of fast-growing conifers. Siberia’s forests are being logged at an incredible rate. Logging in tropical forests is selective but the timber cutters usually prioritise the biggest and oldest trees. In the Amazon, my colleagues and I found the mortality rate for the biggest trees had tripled in small patches of rainforest surrounded by pasture land. This happens for two reasons. First, as they grow taller, big trees become thicker and less flexible: when winds blow across the surrounding cleared land, there is nothing to stop their acceleration. When they hit the trees, the impact can snap them in half. Second, rainforest fragments dry out when surrounded by dry, hot pastures and the resulting drought can have devastating consequences: one four-year study has shown that death rates will double for smaller trees but will increase 4.5 times for bigger trees.

G. Particular enemies to large trees are insects and disease. Across vast areas of western North America, increasingly mild winters are causing massive outbreaks of bark beetle. These tiny creatures can kill entire forests as they tunnel their way through the inside of trees. In both North America and Europe, fungus-causing diseases such as Dutch elm disease have killed off millions of stately trees that once gave beauty to forests and cities. As a result of human activity, such enemies reach even the remotest corners of the world, threatening to make the ancient giants a thing of the past.

Questions 8-13
Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 8-13.
8. The biggest trees in the world can be found in……………………….
9. Some trees in northern Australia die because of…………………………made worse by gamba grass.
10. The Clarks believe that the release of………………………….from dead trees could lead to the death of more trees.
11. Strong…………………………………are capable of damaging tall trees in the Amazon.
12. …………………………………..has a worse impact on tall trees than smaller ones.
13. In western Northern America, a species of……………………………….has destroyed many trees.

63. Bài 63

Whale Strandings

Why do whales leave the ocean and become stuck on beaches?

When the last stranded whale of a group eventually dies, the story does not end there. A team of researchers begins to investigate, collecting skin samples for instance, recording anything that could help them answer the crucial question: why? Theories abound, some more convincing than others. In recent years, navy sonar has been accused of causing certain whales to strand. It is known that noise pollution from offshore industry, shipping and sonar can impair underwater communication, but can it really drive whales onto our beaches?

In 1998, researchers at the Pelagos Cetacean Research Institute, a Greek non-profit scientific group, linked whale strandings with low- frequency sonar tests being carried out by the North Atlantic Treaty Organisation (NATO). They recorded the stranding of 12 Cuvier’s beaked whales over 38.2 kilometres of coastline. NATO later admitted it had been testing new sonar technology in the same area at the time as the strandings had occurred. ‘Mass’ whale strandings involve four or more animals. Typically they all wash ashore together, but in mass atypical strandings (such as the one in Greece), the whales don’t strand as a group; they are scattered over a larger area.

For humans, hearing a sudden loud noise might prove frightening, but it does not induce mass fatality. For whales, on the other hand, there is a theory on how sonar can kill. The noise can surprise the animal, causing it to swim too quickly to the surface. The result is decompression sickness, a hazard human divers know all too well. If a diver ascends too quickly from a high-pressure underwater environment to a lower-pressure one, gases dissolved in blood and tissue expand and form bubbles. The bubbles block the flow of blood to vital organs, and can ultimately lead to death.

Plausible as this seems, it is still a theory and based on our more comprehensive knowledge of land-based animals. For this reason, some scientists are wary. Whale expert Karen Evans is one such scientist. Another is Rosemary Gales, a leading expert on whale strandings. She says sonar technology cannot always be blamed for mass strandings. “It’s a case-by-case situation. Whales have been stranding for a very long time – pre-sonar.” And when 80% of all Australian whale strandings occur around Tasmania, Gales and her team must continue in the search for answers.

When animals beach next to each other at the same time, the most common cause has nothing to do with humans at all. “They’re highly social creatures,” says Gales. “When they mass strand – it’s complete panic and chaos. If one of the group strands and sounds the alarm, others will try to swim to its aid, and become stuck themselves.”

Activities such as sonar testing can hint at when a stranding may occur, but if conservationists are to reduce the number of strandings, or improve rescue operations, they need information on where strandings are likely to occur as well. With this in mind, Ralph James, physicist at the University of Western Australia in Perth, thinks he may have discovered why whales turn up only on some beaches. In 1986 he went to Augusta, Western Australia, where more than 100 false killer whales had beached. “I found out from chatting to the locals that whales had been stranding there for decades. So I asked myself, what is it about this beach?” From this question that James pondered over 20 years ago, grew the university’s Whale Stranding Analysis Project.

Data has since revealed that all mass strandings around Australia occur on gently sloping sandy beaches, some with inclines of less than 0.5%. For whale species that depend on an echolocation system to navigate, this kind of beach spells disaster. Usually, as they swim, they make clicking noises, and the resulting sound waves are reflected in an echo and travel back to them. However, these just fade out on shallow beaches, so the whale doesn’t hear an echo and it crashes onto the shore.

But that is not all. Physics, it appears, can help with the when as well as the where. The ocean is full of bubbles. Larger ones rise quickly to the surface and disappear, whilst smaller ones – called microbubbles – can last for days. It is these that absorb whale ‘clicks! “Rough weather generates more bubbles than usual,” James adds. So, during and after a storm, echolocating whales are essentially swimming blind.

Last year was a bad one for strandings in Australia. Can we predict if this – or any other year – will be any better? Some scientists believe we can. They have found trends which could be used to forecast ‘bad years’ for strandings in the future. In 2005, a survey by Klaus Vanselow and Klaus Ricklefs of sperm whale strandings in the North Sea even found a correlation between these and the sunspot cycle, and suggested that changes in the Earth’s magnetic field might be involved. But others are sceptical. “Their study was interesting … but the analyses they used were flawed on a number of levels,” says Evans. In the same year, she co-authored a study on Australian strandings that uncovered a completely different trend. “We analysed data from 1920 to 2002 … and observed a clear periodicity in the number of whales stranded each year that coincides with a major climatic cycle.” To put it more simply, she says, in the years when strong westerly and southerly winds bring cool water rich in nutrients closer to the Australia coast, there is an increase in the number of fish. The whales follow.

So what causes mass strandings? “It’s probably many different components,” says James. And he is probably right. But the point is we now know what many of those components are.

Questions 14-17
Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 14-17 on your answer sheet.
14. What do researchers often take from the bodies of whales?
15. What do some industries and shipping create that is harmful to whales?
16. In which geographical region do most whale strandings in Australia happen?
17. Which kind of whale was the subject of a study in the North Sea?

Questions 18-21

Label the diagram below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 18-21 on your answer sheet.

Whale Strandings

Questions 22-26
Do the following statements agree with the information given in Reading Passage 2? In boxes 22-26 on your answer sheet, write:
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

22. The aim of the research by the Pelagos Institute in 1998 was to prove that navy sonar was responsible for whale strandings.
23. The whales stranded in Greece were found at different points along the coast.
24. Rosemary Gales has questioned the research techniques used by the Greek scientists.
25. According to Gales, whales are likely to try to help another whale in trouble.
26. There is now agreement amongst scientists that changes in the Earth’s magnetic fields contribute to whale strandings.

64. Bài 64

Fatal Attraction

Evolutionist Charles Darwin first marvelled at flesh-eating plants in the mid-19th century. Today, biologists, using 21st-century tools to study cells and DNA, are beginning to understand how these plants hunt, eat and digest – and how such bizarre adaptations arose in the first place.

A. The leaves of the Venus flytrap plant are covered in hairs. When an insect brushes against them, this triggers a tiny electric charge, which travels down tunnels in the leaf and opens up pores in the leaf’s cell membranes. Water surges from the cells on the inside of the leaf to those on the outside, causing the leaf to rapidly flip in shape from convex to concave, like a soft contact lens. As the leaves flip, they snap together, trapping the insect in their sharp-toothed jaws.

B. The bladderwort has an equally sophisticated way of setting its underwater trap. It pumps water out of tiny bag-like bladders, making a vacuum inside. When small creatures swim past, they bend the hairs on the bladder, causing a flap to open. The low pressure sucks water in, carrying the animal along with it. In one five-hundredth of a second, the door swings shut again. The Drosera sundew, meanwhile, has a thick, sweet liquid oozing from its leaves, which first attracts insects, then holds them fast before the leaves snap shut. Pitcher plants use yet another strategy, growing long tube-shaped leaves to imprison their prey. Raffles’ pitcher plant, from the jungles of Borneo, produces nectar that both lures insects and forms a slick surface on which they can’t get a grip. Insects that land on the rim of the pitcher slide on the liquid and tumble in.

C. Many carnivorous plants secrete enzymes to penetrate the hard exoskeleton of insects so they can absorb nutrients from inside their prey. But the purple pitcher plant, which lives in bogs and infertile sandy soils in North America, enlists other organisms to process its food. It is home to an intricate food web of mosquito larvae, midges and bacteria, many of which can survive only in this unique habitat. These animals shred the prey that fall into the pitcher, and the smaller organisms feed on the debris. Finally, the plant absorbs the nutrients released.

D. While such plants clearly thrive on being carnivorous, the benefits of eating flesh are not the ones you might expect. Carnivorous animals such as ourselves use the carbon in protein and the fat in meat to build muscles and store energy. Carnivorous plants instead draw nitrogen, phosphorus, and other critical nutrients from their prey in order to build light-harvesting enzymes. Eating animals, in other words, lets carnivorous plants do what all plants do: carry out photosynthesis, that is, grow by harnessing energy directly from the sun.

E. Carnivorous plants are, in fact, very inefficient at converting sunlight into tissue. This is because of all the energy they expend to make the equipment to catch animals – the enzymes, the pumps, and so on. A pitcher or a flytrap cannot carry out much photosynthesis because, unlike plants with ordinary leaves, they do not have flat solar panels that can grab lots of sunlight. There are, however, some special conditions in which the benefits of being carnivorous do outweigh the costs. The poor soil of bogs, for example, offers little nitrogen and phosphorus, so carnivorous plants enjoy an advantage over plants that obtain these nutrients by more conventional means. Bogs are also flooded with sunshine, so even an inefficient carnivorous plant can photosynthesise enough light to survive.

F. Evolution has repeatedly made this trade-off. By comparing the DNA of carnivorous plants with other species, scientists have found that they evolved independently on at least six separate occasions. Some carnivorous plants that look nearly identical turn out to be only distantly related. The two kinds of pitcher plants – the tropical genus Nepenthes and the North American Sarracenia – have, surprisingly, evolved from different ancestors, although both grow deep pitchershaped leaves and employ the same strategy for capturing prey.

G. In several cases, scientists can see how complex carnivorous plants evolved from simpler ones. Venus flytraps, for example, share an ancestor with Portuguese sundews, which only catch prey passively, via ‘flypaper’ glands on their stems. They share a more recent ancestor with Drosera sundews, which can also curl their leaves over their prey. Venus flytraps appear to have evolved an even more elaborate version of this kind of trap, complete with jaw-like leaves.

H. Unfortunately, the adaptations that enable carnivorous plants to thrive in marginal habitats also make them exquisitely sensitive