01:18

• 21, 22 Which TWO of the following are specifications for the activity that Sophie and James are going to design?
• A it should relate to articles the students have read
• B it should require few resources
• C it should have been one of the lecturer's suggestions
• D it could be used in a company setting
• E it could be completed in a single session
• 23, 24 Which TWO of the following opinions do Sophie and James express about small-group activities in their class?
• A students learn a lot from each other
• B groups are usually based on friendships
• C students generally enjoy the activities
• D the activities seem to be very effective
• E individuals focus on their own needs
• 25, 26 Which TWO of the following aims do Sophie and James have for their assignment?
• A to identify potential leaders
• B to compare different personality types
• C to evaluate a new way of working
• D to increase students' independence
• E to increase students' self-awareness

LARGE-SCALE SURVEYS

CASE STUDY 1: SINGAPORE

General Household Survey (GHS) 2005

Subjects

•	Included residents and non-residents who were long-stay (e.g. foreign 31 and students)
•	Excluded short-stay groups (e.g. 32 )

Sources

•	Information about individuals from 33 , e.g. sex, age, ethnic group, house type (updated)
•	Information from survey of 8 percent of 34 e.g. marital status, education, overseas travel

Survey methods

•	via 35
•	via telephone
•	via face-to-face interview (NB use of hand-held 36 for first time)

Information collected over 12–15 weeks. All data recorded electronically.

Data processing

Data checked for accuracy --> data edited -->37 produced --> comprehensive profile of Singaporeans published

Trends

Identified by comparing surveys, e.g. 2000–2005

•	resident population increased by 1.7 percent
•	proportion of over 65s increased by 1.1 percent
•	38 ratio decreased by 3 percent
•	proportion of young 39 people rose from 31 percent to 34 percent (men) and 19 percent to 22 percent (women)

NB

Information from surveys like GHS allows government to 40 more effectively.

Birds of land and water

Of the 8,600 species of bird, about 7,500 – over 85% of all species – live in close association with land or fresh water. In these birds, there are often clear differences between the sexes, in size, colour and feather patterns. The diversity of their habitats and diets in comparison to sea birds has led to a greater range of territorial and mating behaviour, as well as great variations in size, shape and aerodynamics. Most of the land birds belong to a single order (the perching birds), and it is with these that the clearest distinction between land and sea birds – birdsong – has reached its greatest development.

Ground and perching birds

While the forelimbs of birds are modified into wings, the hind, or pelvic limbs – the legs – are usually covered in scales and armed with curving nails, the claws. Ground birds use their claws to dig and gather food, while perching birds use them to grip branches. Three digits face forwards for propulsion, and one faces backwards as a support, but is sometimes reduced in size and function.

In owls and tree-living birds such as woodpeckers and trogons, the third toe also faces backwards, increasing the strength of their grip. In owls, all toes are equally well developed, with very sharp talons for grappling with prey. Parrots use their beaks for climbing, using the upper part to lever themselves up. Young hoatzin, primitive South American galliforms, have clawed thumbs on their wings, which they use for scrambling through trees.

Flightless birds

The ten species of flightless birds are the most primitive birds, and are the remnants of a group once found worldwide. They have flat breastbones, often large legbones and wings that are reduced in size. It is now thought that such birds were probably never capable of flying.

Apart from the kiwi of New Zealand, which is 50 cm tall, flightless birds range in size from 1.5 m to the largest living bird – the ostrich of Africa – towering above humans at up to 2.75 m. The group also includes the cassowaries of Australia and New Guinea, the rheas of South America, and the emu of Australia. Their feathers are hair- or plume-like. Several females often lay in the same nest, and the eggs are often incubated by the male. The egg of an ostrich is equal in volume to 25–40 chicken eggs, while the huge extinct elephant birds of Madagascar laid eggs that weighed around ten kilos.

Some species of flying bird, such as the New Zealand rails and the kakapo, a nocturnal parrot, have become flightless, usually in island habitats, in the absence of predators. Some birds are now under severe pressure both from humans and from introduced predators.

Swimmers and divers

Unlike sea birds such as penguins, which use their wings as flippers, propulsion in fresh water birds is generally achieved by kicking with powerful legs. Ducks, swans and loons (divers) have webbed feet, while grebes and finfoots have fringed, paddle-like toes. Most water birds dabble and dive for plants, insects, molluscs and crustaceans. The dipper, a bird that hunts crustaceans and larvae in fast mountain streams in the northern hemisphere, lacks strong legs, and swims using its wings instead. Dippers and divers have flexible lenses in their eyes, allowing them to see as well under water as in the air. Like sea birds, water birds have well-developed preen glands to waterproof their feathers.

Feather colours

The colours of birds' feathers are produced by a combination of structural effects and actual pigments in the feathers. Light may be absorbed or dispersed by feathers, resulting in unshiny dark or light areas, or may be diffracted by the feather filaments, producing the marvellous iridescence and metallic sheens seen, for example, on starling and peacock feathers.

Most reds and oranges result from the presence of carotenoid pigments related to Vitamin A, and the light-sensitive retinal pigment rhodopsin, which comes from foodstuffs. Melanin, the dark pigment associated with mammalian hair and dark skin, is responsible for yellows, browns, greens and blues. Turacos, African birds related to cuckoos, have brilliant red and green colours different from those of all other birds. These colours are based on copper-containing pigments related to haemoglobin, the oxygen-carrying protein in red blood cells.

Bird Senses

For most birds, vision is the most important sense. Nocturnal birds, such as owls, frogmouths and nightjars, have large eyes with a high proportion of rods – retinal cells sensitive to movement in dim light. The barn owl's sight is up to 100 times better than a human's.

Acute hearing can also be important. Owls have earflaps which are slightly asymmetrical, allowing them to fix the position of noises more accurately. They also have large eardrums to amplify sounds. The softness of their feathers results in almost silent flight – an adaptation that fishing owls lack, not needing silence to catch their prey. Oilbirds, relatives of the nightjar, also rely on their hearing, although not in order to detect prey – they eat seeds and fruits. They live in dark caves, where they navigate by listening to the echoes of their vocal clicks.

Smell is generally poorly developed in birds, but a notable exception is the kiwi. It has very small eyes, and detects earthworms and grubs by smell, having nostrils at the very tip of its long, flexible beak. The part of the kiwi's brain associated with smell is far better developed than in all other birds. Parrots use their tongue a great deal, rolling nuts and seeds round in their beaks to test their shape and find a good place to start chewing.

• 1There is greater diversity amongst land birds than amongst sea birds. TRUEFALSENOT GIVEN
• 2Perching birds find the majority of their food in trees. TRUEFALSENOT GIVEN
• 3Owls have three forward-facing toes and one backward-facing toe. TRUEFALSENOT GIVEN
• 4Young hoatzin shed their wing claws as they mature. TRUEFALSENOT GIVEN
• 5The New Zealand kiwi is the shortest of the flightless birds. TRUEFALSENOT GIVEN
• 6Every nest is used exclusively by one female ostrich. TRUEFALSENOT GIVEN
• 7Some birds in safe habitats have lost the ability to fly. 
• 8Which feature facilitates good underwater vision in dippers and divers? 
• 9Which birds have a unique form of colour? 
• 10What are in different positions on each side of the owl's body? 
• 11What quality of their feathers enables owls to fly quietly? 
• 12What do oilbirds use their hearing to do? 
• 13Which bird has a particularly keen sense of smell? 

Peer* interaction and problem solving

A

Over the past fifteen years, various studies have addressed whether, when and how interaction with their peers facilitates children's cognitive development. One of the tasks long favoured by cognitive psychologists who are interested in problem solving is the 'Tower of Hanoi'. This is usually presented in the form of a board with three vertical pegs in it; over one peg is slipped a number of different-sized tiles, with the largest at the bottom and the smallest at the top, so that they form a pagoda-shaped stack. The task is to dismantle the 'pagoda' and re-form it on one of the other pegs, but with the constraints that only one tile can be moved at a time, and that a larger tile may never be placed on a smaller one. With three tiles, the problem is solvable in a minimum of seven moves.

B

Our own first exploration of the effects of peer interaction on problem-solving ability began with this task (Glachan and Light, 1982: Light and Glachan, 1985). We pre-tested individual children aged about eight, and then assigned them at random to either a control condition, where they worked alone, or an experimental condition where they worked in pairs, sitting opposite one another with the board between them. We then post-tested them all individually with a slightly different version of the task. In this first study, we obtained no evidence that the children who had worked together gained any advantage from doing so. However, when we looked more closely at what they were actually doing, this offered no surprise. The children were simply taking turns, having one move or a whole trial each, but taking little interest when it was 'not their go'. So we attached little handles to each side of the tiles and tried again with a rule which stipulated that they must cooperate on all moves, and that no move could be made unless the two children moved the tile together. Under these conditions we did get evidence that children who worked together did better, and carried over some of this advantage to individual post-test.

C

What counts, seemingly, is for the children to be engaged with one another as well as with the task. Blaye (1988) came to the same conclusion on the basis of a series of studies involving five- and six-year-olds in a matrix-filling task presented to them on computer. Whilst the experience of working in a pair often led to greater individual progress than working alone, this was particularly noticeable when one of the children was required to indicate their choice with a lightpen, while the other had to affirm their consent by using the keyboard. Once again it is co-ordinating the roles of the children that seems to be important.

D

In our own work we have experimented with a number of other computer-presented 'puzzles', one being a computer version of the pegboard code-breaking game 'Mastermind'. The computer generated a digital code sequence which the children had to 'break' by trying out different sequences and getting feedback (Light and Glachan, 1985). In this study, the children who worked together again enjoyed some advantage over those who worked alone. In an attempt to understand the basis of this facilitation, we tape-recorded the interaction between the children. We looked in particular for 'arguments', i.e., sequences where the children were offering differing suggestions as to what move to make next, and where at least one of them was offering some kind of justification. As it happened, such arguments were fairly common in about half of the pairs and rather scarce in the other half. The improvement of children's scores from pre-test to post-test was significantly greater in those pairs who engaged in frequent argument than it was for the remainder.

E

This study then offered some support for the view that 'socio-cognitive conflict', or at least disagreement, may be a necessary condition for progress in peer interaction situations. More evidence comes from a more recent series of studies by Christine Howe and colleagues. These were conducted with secondary-school-aged pupils using computer-based tasks related to the physics curriculum. The design of these studies has followed the familiar pattern of individual pre-tests and post-tests, and in between, a session in which children work together in pairs or small groups. In one study concerning trajectories of objects dropped from planes, Howe formed pairs on the basis of pre-test responses, such that students (12- and 14-year-olds) in a pair were either similar or different in terms of their initial predictions and conceptions. The pairs which showed the greatest pre- to post-test gains were those where the students differed both in terms of the trajectories they predicted and the conceptions on which these predictions were based.

F

While the work of Howe and colleagues lends support to the idea that socio-cognitive conflict may be the key ingredient in peer facilitation of learning, other researchers have raised doubts about this, and have criticized the concept of conflict as vague and ill-defined (Blaye, 1988). Some researchers have found that interaction between children at the same level is actually sometimes the most effective situation. Thus, for example, Light et al. (1994), using a detour problem-solving task couched as a computer adventure game, found that working with a partner of the same pre-test score level was more effective than working with a lower-level or a higher-level partner. So there appear to be at least some circumstances under which learners need to be evenly matched to maximize the productivity of the interaction. One explanation may be the fact that the task in this experiment was wholly novel for both partners: they were not coming to the situation with well-formed views of how the problem should be tackled, as they were in the case of Howe et al.'s study, so they were engaged in jointly constructing the solution to the problem.

* person of similar age

• 14an explanation as to why one experiment focused on children's conversation 
• 15a description of how a conventional problem-solving task was modified 
• 16an attempt to reconcile conflicting research findings 
• 17a description of the equipment used in a popular experiment 
• 18challenges to claims about the significant role of disagreement 

• 19original 'Tower of Hanoi': list of findings
• A Children who shared similarities gained the most from working in pairs.
  B Children who differed gained the most from working in pairs.
  C Children gained no advantage from working in pairs.
  
• 20'Mastermind': list of findings
• A Children who shared similarities gained the most from working in pairs.
  B Children who differed gained the most from working in pairs.
  C Children gained no advantage from working in pairs.
  
• 21physics problem: list of findings
• A Children who shared similarities gained the most from working in pairs.
  B Children who differed gained the most from working in pairs.
  C Children gained no advantage from working in pairs.
  
• 22detour problem: list of findings
• A Children who shared similarities gained the most from working in pairs.
  B Children who differed gained the most from working in pairs.
  C Children gained no advantage from working in pairs.

Children's cognitive development

Psychologists are interested in whether children's cognitive development is helped when they discuss problems with their 23 . 

One experiment found that children who were solving a manual problem in pairs were acting in 24 instead of cooperating with each other. The same researchers found that when the children engaged with each other, their problem-solving ability seemed to increase. However, pairs of children who often had 25 about a problem seemed to benefit the most. 

Other studies found that pairs of children who were equally matched for ability seemed to benefit the most. The writer concludes that tasks which are completely 26 for both children may create the best opportunity for learning.

The global decline of fish stocks

Recent research has given us a better understanding of the unexploited sizes of fish populations, which often turn out to be much higher than were previously assumed by scientists. This systematic underestimation of pristine populations has led to the target-population sizes believed necessary to achieve maximum sustainable yield being set too low, thus leading to a greater risk of population collapses.

Fishery managers and politicians have long taken comfort from the idea that mistakes in fisheries are simple to reverse by easing back on fishing pressure. In some fisheries this has proven true. The overfished Pacific halibut, for example, recovered in the early twentieth century when an international agreement was reached to scale back fishing effort. Northern populations of herring bounced back after the 1970s moratorium in Europe. Peruvian anchoveta  struggled back after spectacular collapses in the early 1970s and the mid-1980s. Striped bass  rallied in eastern North America in the 1980s.

But for every case of recovery, there are several counter-examples. The Baltic Scanian herring  disappeared hundreds of years ago and has never come back. North Atlantic halibut, once a mainstay of line fishers, crashed in the nineteenth century and has been a bit player ever since. Nassau grouper  once held sway on Caribbean reefs, but in most countries are scarcely seen today. The days when Gulf of California waters boiled with spawning runs of totoaba are over, and the majestic bluefin  tuna has lost its crown in the Atlantic. Jeff Hutchings, from Canada's Dalhousie University, looked for evidence of recovery in ninety different commercially exploited fish populations after they had declined by between 13 and 90 percent. Only a handful of these made a full recovery when fishing was reduced. He also looked at long-term recovery success for twenty-five populations for which at least fifteen years of post-decline data were available: only 12 per cent made a full recovery, all of them small, open-water species from the herring family. 40 percent showed no recovery at all.

The most notorious example of non-recovery is that of cod on the Grand Banks off the east coast of Canada, which was reduced to less than one percent of its unexploited population size. All kinds of theories have been advanced to explain why cod did not rebound after the fishing moratorium was declared in 1992. Some argue that the conversion of capelin  shoals into fishmeal prevents recovery because capelin are a staple food of cod. But the offshore capelin fishery was closed in 1991, and nearshore catches have been reduced in recent years. On the other hand, some scientists point to the fact that capelin are predators of cod larvae, so too many capelin may hold back recovery, and fishing them could be good for cod. Others, notably seal hunters, say there are too many harp seals  and they are eating young cod. Their views have fuelled calls for increased culls of seal pups. Certainly, research surveys suggest that mortality of the few juvenile cod around is extremely high, but nobody is sure why. One reason, perhaps, is that cod are still a by-catch of other fisheries on the Grand Banks. It is impossible to avoid catching all cod unless you stop fishing altogether. Scallop  and crab  fishers, and prawn  trawlers still work the banks, as do others. And then, of course, there is that old standby when all other explanations fail: the weather was wrong for cod.

Bottom trawling in all its forms has done untold damage to seabed habitats. It has ripped up complex habitats built by slow-growing invertebrates over millennia. It has rearranged geology, grinding down rocky shelves, smoothing sand waves, planing mounds, and obliterating reefs. In smoothing out three-dimensional relief and removing upright animals, trawling has rendered the bottom a more hostile environment for species that depend on complexity. The transformation of the sea bottom by trawlers may be one reason Atlantic halibut has failed to recover, and it contributes to the high mortality of young cod on the Grand Banks.

Finally, perhaps recovery of cod is held back because young fish can no longer find their way to spawning sites. Before stocks collapsed, George Rose, of Newfoundland's Memorial University, used sonar equipment to study shoals of cod massing to spawn at the edge of Newfoundland's continental shelf. Pulses of sound bounced off fish allowed Rose to see details of the size and shape of shoals, and even to resolve individual fish. Fish massed at the edge of the shelf in shoals tens of kilometres wide and consisting of hundreds of millions of fish. Fish rose in columns from the main body of these shoals to spawn, with paired males and females releasing eggs and sperm together. When spawning was complete, the fish headed across the shelf in mixed bodies of adult and immature cod. They followed deep channels cut through the shelf, keeping to fingers of warm oceanic water sitting below the colder overlying sea. Fishing wiped out the large, old fish, referred to as scouts by Rose. The same could be true of the Nassau grouper in the Caribbean. Every year these animals gathered to spawn at traditional mating sites, some travelling tens to more than a hundred kilometres to reach the sites. Aggregations numbered tens of thousands of fish. In a pattern repeated across the region, when fishers discovered a site, it was fished to exhaustion in only a few years. Nobody knows how Nassau groupers found spawning sites. Once lost, though, there is little evidence that spawning aggregations can recover. With the experienced fish gone, the few young that are still around may never find these places.

• 27According to the writer, why are targets for fish stock levels set too low?
• A Scientists formerly miscalculated natural stock levels.
  B Fishery managers put pressure on politicians to allow large catches.
  C Numbers of unexploited populations were previously exaggerated.
  D Formulae used to calculate population sizes are still very inaccurate.
  
• 28When measures have been taken to reduce fishing
• A few fish populations have fully recovered.
  B there has been no long-term impact on fish populations.
  C some fish species exceeded their original numbers.
  D population sizes took longer than expected to increase.
  
• 29What does the writer say about the continuing decline of cod on the Grand Banks since 1992?
• A There are several different reasons for the decline.
  B It is not certain what the reason for the decline is.
  C Scientists are generally in agreement about the cause of the decline.
  D Lack of regulation is the main cause of the decline.
  
• 30What does George Rose's research seem to suggest?
• A Fish have an instinctive sense of where to spawn.
  B Cod stocks off Newfoundland are now abundant.
  C After spawning, cod steer through cold water courses.
  D Young cod learn to navigate from older cod.

• 31The optimism of fishery managers and politicians concerning fish conservation is justified. YESNONOT GIVEN
• 32Controls on fishing for anchoveta are still in force in Peru. YESNONOT GIVEN
• 33Hutchings's research supports the view that regulation has limited benefits for fish stocks. YESNONOT GIVEN
• 34In eastern Canada, capelin have not been fished offshore since 1991. YESNONOT GIVEN
• 35Canadian quotas for hunting harp seals are to be increased. YESNONOT GIVEN
• 36Trawlers do little harm to marine habitats. 

• 37The Pacific halibut …
• A was the subject of research by Newfoundland Memorial University.
  B feeds on the larvae of another fish.
  C responded well to a reduction in fishing catch.
  D may have declined for climatic reasons.
  E may have lost the ability to locate spawning sites.
  F has not been seen for centuries.
  G is dying in large numbers before reaching maturity.
  
• 38The Scanian herring …
• A was the subject of research by Newfoundland Memorial University.
  B feeds on the larvae of another fish.
  C responded well to a reduction in fishing catch.
  D may have declined for climatic reasons.
  E may have lost the ability to locate spawning sites.
  F has not been seen for centuries.
  G is dying in large numbers before reaching maturity.
  
• 39The capelin …
• A was the subject of research by Newfoundland Memorial University.
  B feeds on the larvae of another fish.
  C responded well to a reduction in fishing catch.
  D may have declined for climatic reasons.
  E may have lost the ability to locate spawning sites.
  F has not been seen for centuries.
  G is dying in large numbers before reaching maturity.
  
• 40The Nassau grouper …
• A was the subject of research by Newfoundland Memorial University.
  B feeds on the larvae of another fish.
  C responded well to a reduction in fishing catch.
  D may have declined for climatic reasons.
  E may have lost the ability to locate spawning sites.
  F has not been seen for centuries.
  G is dying in large numbers before reaching maturity.