Short Answers and Identifying Information

The dodo was a large bird which did not possess wings. It evolved only on the island of Mauritius, in the Indian Ocean, and it became extinct in the eighteenth century. After a lot of debate, scientists concluded that there were three reasons for this.

Firstly, before humans arrived in Mauritius in the seventeenth century the dodos had no natural predators. As a result they were not afraid of the travellers, so it was very easy to hunt them for food.

In addition, the humans who landed in Mauritius brought with them many foreign animals which were not native to the island, such as pigs, dogs and macaques. Reports say that these animals often raided the dodos' nests to take their young.

Finally, as more and more of Mauritius became colonised by humans, who wanted to harvest its natural resources, the dodos' habitat decreased considerably. Eventually they had too little territory to live and reproduce successfully.

A millennium ago, stepwells were fundamental to life in the driest parts of India. Although many have been neglected, recent restoration has returned them to their former glory. Richard Cox travelled to north-western India to document these spectacular monuments from a bygone era.

During the sixth and seventh centuries, the inhabitants of the modern-day states of Gujarat and Rajasthan in North-western India developed a method of gaining access to clean, fresh groundwater during the dry season for drinking, bathing, watering animals and irrigation. However, the significance of this invention - the stepwell - goes beyond its utilitarian application.

Unique to the region, stepwells are often architecturally complex and vary widely in size and shape. During their heyday, they were places of gathering, of leisure, of relaxation and of worship for villagers of all but the lowest castes.

Most stepwells are found dotted around the desert areas of Gujarat (where they are called vav) and Rajasthan (where they are known as baori), while a few also survive in Delhi. Some were located in or near villages as public spaces for the community; others were positioned beside roads as resting places for travellers.

As their name suggests, stepwells comprise a series of stone steps descending from ground level to the water source (normally an underground aquifer) as it recedes following the rains. When the water level was high, the user needed only to descend a few steps to reach it; when it was low, several levels would have to be negotiated.

Some wells are vast, open craters with hundreds of steps paving each sloping side, often in tiers. Others are more elaborate, with long stepped passages leading to the water via several storeys built from stone and supported by pillars; they also included pavilions that sheltered visitors from the relentless heat. But perhaps the most impressive features are the intricate decorative sculptures that embellish many stepwells, showing activities from fighting and dancing to everyday acts such as women combing their hair and churning butter.

Down the centuries, thousands of wells were constructed throughout northwestern India, but the majority have now fallen into disuse; many are derelict and dry, as groundwater has been diverted for industrial use and the wells no longer reach the water table. Their condition hasn't been helped by recent dry spells: southern Rajasthan suffered an eight-year drought between 1996 and 2004.

However, some important sites in Gujarat have recently undergone major restoration, and the state government announced in June last year that it plans to restore the stepwells throughout the state.

In Patan, the state's ancient capital, the stepwell of Rani Ki Vav (Queen's Stepwell) is perhaps the finest current example. It was built by Queen Udayamati during the late 11th century, but became silted up following a flood during the 13th century. But the Archaeological Survey of India began restoring it in the 1960s, and today it's in pristine condition. At 65 metres long, 20 metres wide and 27 metres deep, Rani Ki Vav features 500 distinct sculptures carved into niches throughout the monument, depicting gods such as Vishnu and Parvati in various incarnations. Incredibly, in January 2001, this ancient structure survived a devastating earthquake that measured 7.6 on the Richter scale.

Another example is the Surya Kund in Modhera, northern Gujarat, next to the Sun Temple, built by King Bhima I in 1026 to honour the sun god Surya. It's actually a tank (kund means reservoir or pond) rather than a well, but displays the hallmarks of stepwell architecture, including four sides of steps that descend to the bottom in a stunning geometrical formation. The terraces house 108 small, intricately carved shrines between the sets of steps.

Rajasthan also has a wealth of wells. The ancient city of Bundi, 200 kilometres south of Jaipur, is renowned for its architecture, including its stepwells. One of the larger examples is Raniji Ki Baori, which was built by the queen of the region, Nathavatji, in 1699. At 46 metres deep, 20 metres wide and 40 metres long, the intricately carved monument is one of 21 baoris commissioned in the Bundi area by Nathavatji.

In the old ruined town of Abhaneri, about 95 kilometres east of Jaipur, is Chand Baori, one of India's oldest and deepest wells; aesthetically, it's perhaps one of the most dramatic. Built in around 850 AD next to the temple of Harshat Mata, the baori comprises hundreds of zigzagging steps that run along three of its sides, steeply descending 11 storeys, resulting in a striking geometric pattern when seen from afar. On the fourth side, covered verandas supported by ornate pillars overlook the steps.

Still in public use is Neemrana Ki Baori, located just off the Jaipur-Delhi highway. Constructed in around 1700, it's nine storeys deep, with the last two levels underwater. At ground level, there are 86 colonnaded openings from where the visitor descends 170 steps to the deepest water source.

Today, following years of neglect, many of these monuments to medieval engineering have been saved by the Archaeological Survey of India, which has recognised the importance of preserving them as part of the country's rich history. Tourists flock to wells in far-flung corners of northwestern India to gaze in wonder at these architectural marvels from 1,000 years ago, which serve as a reminder of both the ingenuity and artistry of ancient civilisations and of the value of water to human existence.

The question of whether we are alone in the Universe has haunted humanity for centuries, but we may now stand poised on the brink of the answer to that question, as we search for radio signals from other intelligent civilizations. This search, often known by the acronym SETI [search for extraterrestrial intelligence], is a difficult one. Although groups around the world have been searching intermittently for three decades, it is only now that we have reached the level of technology where we can make a determined attempt to search all nearby stars for any sign of life.

A. The primary reason for the search is basic curiosity - the same curiosity about the natural world that drives all pure science. We want to know whether we are alone in the Universe. We want to know whether life evolves naturally if given the right conditions, or whether there is something very special about the Earth to have fostered the variety of life forms that we see around us on the planet. The simple detection of a radio signal will be sufficient to answer this most basic of all questions. In this sense, SETI is another cog in the machinery of pure science which is continually pushing out the horizon of our knowledge. However, there are other reasons for being interested in whether life exists elsewhere. For example, we have had civilization on Earth for perhaps only a few thousand years, and the threats of nuclear war and pollution over the last few decades have told us that our survival may be tenuous. Will we last another two thousand years or will we wipe ourselves out? Since the lifetime of a planet like ours is several billion years, we can expect that if other civilizations do survive in our galaxy, their ages will range from zero to several billion years. Thus any other civilization that we hear from is likely to be far older on average than ourselves. The mere existence of such a civilization will tell of that long-term survival is possible, and gives us some cause for optimism. It is even possible that the older civilization may pass on the benefits of their experience in dealing with threats to survival such as nuclear war and global pollution, and other threats that we haven't yet discovered.

B. In discussing whether we are alone, most SETI scientists adopt two ground rules. First, UFOs [Unidentified Flying objects] are generally ignored since most scientists don't consider the evidence for them to be strong enough to bear serious consideration (although it is also important to keep an open mind in case any really convincing evidence emerges in the future). Second, we make a very conservative assumption that we are looking for a life form that is pretty well like us, since if it differs radically from us we may well not recognize it as a life form, quite apart from whatever we are able to communicate with it. In other words, the life form we are looking for may well have two green heads and seven fingers, but it will nevertheless resemble us in that it should communicate with its fellows. Be interested in the Universe, Live on a planet orbiting a star like our Sun, and perhaps most restrictively have chemistry, like us, based on carbon and water.

C. Even when we make these assumptions, our understanding of other life forms is still severely limited. We do not even know, for example, how many stars have planets, and we certainly do not know how likely it is that life will arise naturally, given the right conditions. However, when we look at the 100 billion stars in our galaxy [the Milky Way], and 100 billion galaxies. In the observable Universe, it seems inconceivable that at least one of these planets does not have a life form on it; in fact, the best educated guess we can make using the little that we do know about the conditions for carbon-based life, leads us to estimate that perhaps one in 100,000 stars might have a life-bearing planet orbiting it. That means that our nearest neighbors are perhaps 1000 light years away, which is almost next door in astronomical terms.

D. An alien civilization could choose many different ways of sending information across the galaxy, but many of these either require too much energy, or else are severely attenuated while traversing the vast distances across the galaxy. It turns out that, for a given amount of transmitted power, radio waves in the frequency range 1000 to 3000 MHz travel the greatest distance, and so all searches to date have concentrated on looking for radio waves in this frequency range. So far there have been a number of searches by various groups around the world, including Australian searches using the radio telescope at Parkes, New South Wales. Until now there have not been any detections from the few hundred stars which have been searched. The scale of the searches has been increased dramatically since 1992, when the US Congress voted NASA $10 million per year for ten years to conduct a thorough search for extra-terrestrial life. Much of the money in this project is being spent on developing the special hardware needed to search many frequencies at once. The project has two parts. One part is a targeted search using the world's largest radio telescopes. The American-operated telescope in Arecibo, Puerto Rico and the French telescope in Nancy in France. This part of the project is searching the nearest 1000 likely stars with a high sensibility for signals in the frequency range 1000 to 3000 MHz. The other part of the project is an undirected search which is monitoring all of the space with a lower one using the smaller antennas of NASA's Deep Space Network.

E. There is considerable debate over how we should react if we detect a signal from an alien civilization. Everybody agrees that we should not reply immediately. Quite apart from the impracticality of sending a reply over such large distances at short notice, it raises a host of ethical questions that would have to be addressed by the global community before any reply could be sent. Would the human race face culture shock if faced with a superior and much older civilization? Luckily, there is no urgency about this. The stars being searched are hundreds of light years away. so it takes hundreds of years for their signal to reach us, and a further few hundred years for our reply to reach them. It is not important, then, if there's a delay of a few years, or decades, while the human race debates the question of whether to reply and perhaps carefully drafts a reply.

Every day, we hear about software weakness, viruses and hackers that could take all of our money. Because much of this information is exaggerated and sometimes just plain untrue, it is important for us to know exactly what we should do to protect our data.

Firstly, it is important to say that cybercrime is very rare and most attacks can be prevented by having a strong password. Facebook's Chief Security Officer, Alex Stamos, has spent most of his career thinking about how attackers will find weaknesses in computer systems. He has found that there are two simple solutions for the vast majority of users: strong passwords and two-factor authentication.

Chelsea Rochman, an ecologist at the University of California, Davis, has been trying to answer a dismal question: Is everything terrible, or are things just very, very bad?

Rochman is a member of the National Center for Ecological Analysis and Synthesis's marine-debris working group, a collection of scientists who study, among other things, the growing problem of marine debris, also known as ocean trash. Plenty of studies have sounded alarm bells about the state of marine debris; in a recent paper published in the journal Ecology.

Rochman and her colleagues set out to determine how many of those perceived risks are real. Often, Rochman says, scientists will end a paper by speculating about the broader impacts of what they've found. For example, a study could show that certain seabirds eat plastic bags, and go on to warn that whole bird populations are at risk of dying out. 'But the truth was that nobody had yet tested those perceived threats,' Rochman says. 'There wasn't a lot of information.'

Rochman and her colleagues examined more than a hundred papers on the impacts of marine debris that were published through 2013. Within each paper, they asked what threats scientists had studied - 366 perceived threats in all - and what they'd actually found.

In 83 percent of cases, the perceived dangers of ocean trash were proven true. In the remaining cases, the working group found the studies had weaknesses in design and content which affected the validity of their conclusions - they lacked a control group, for example, or used faulty statistics.

Strikingly, Rochman says, only one well-designed study failed to find the effect it was looking for, an investigation of mussels ingesting microscopic bits. The plastic moved from the mussels' stomachs to their bloodstreams, scientists found, and stayed there for weeks - but didn't seem to stress out the shellfish.

While mussels may be fine eating trash, though, the analysis also gave a clearer picture of the many ways that ocean debris is bothersome.

Within the studies they looked at, most of the proven threats came from plastic debris, rather than other materials like metal or wood. Most of the dangers also involved large pieces of debris - animals getting entangled in trash, for example, or eating it and severely injuring themselves.

But a lot of ocean debris is 'microplastic', or pieces smaller than five millimeters. These may be ingredients used in cosmetics and toiletries, fibers shed by synthetic clothing in the wash, or eroded remnants of larger debris. Compared to the number of studies investigating large-scale debris, Rochman's group found little research on the effects of these tiny bits. 'There are a lot of open questions still for microplastic,' Rochman says, though she notes that more papers on the subject have been published since 2013, the cutoff point for the group's analysis.

There are also, she adds, a lot of open questions about the ways that ocean debris can lead to sea-creature death. Many studies have looked at how plastic affects an individual animal, or that animal's tissues or cells, rather than whole populations. And in the lab, scientists often use higher concentrations of plastic than what's really in the ocean. None of that tells us how many birds or fish or sea turtles could die from plastic pollution - or how deaths in one species could affect that animal's predators, or the rest of the ecosystem.

'We need to be asking more ecologically relevant questions,' Rochman says. Usually, scientists don't know exactly how disasters such as a tanker accidentally spilling its whole cargo of oil and polluting huge areas of the ocean will affect the environment until after they've happened. 'We don't ask the right questions early enough,' she says. But if ecologists can understand how the slow-moving effect of ocean trash is damaging ecosystems, they might be able to prevent things from getting worse.

Asking the right questions can help policy makers, and the public, figure out where to focus their attention. The problems that look or sound most dramatic may not be the best places to start. For example, the name of the 'Great Pacific Garbage Patch' - a collection of marine debris in the northern Pacific Ocean - might conjure up a vast, floating trash island. In reality though, much of the debris is tiny or below the surface; a person could sail through the area without seeing any trash at all. A Dutch group called 'The Ocean Cleanup' is currently working on plans to put mechanical devices in the Pacific Garbage Patch and similar areas to suck up plastic. But a recent paper used simulations to show that strategically positioning the cleanup devices closer to shore would more effectively reduce pollution over the long term.

I think clearing up some of these misperceptions is really important,' Rochman says. Among scientists as well as in the media, she says, 'A lot of the images about strandings and entanglement and all of that cause the perception that plastic debris is killing everything in the ocean.' Interrogating the existing scientific literature can help ecologists figure out which problems really need addressing, and which ones they'd be better off - like the mussels - absorbing and ignoring.

A. The working day has just started at the head office of Barclays Bank in London. Seventeen staff are helping themselves to a buffet breakfast as young psychologist Sebastian Bailey enters the room to begin the morning's training session. But this is no ordinary training session. He's not here to sharpen their finance or management skills. He's here to exercise their brains.

B. Today's workout, organised by a company called the Mind Gym in London, is entitled 'having presence'. What follows is an intense 90-minute session in which this rather abstract concept is gradually broken down into a concrete set of feelings, mental tricks and behaviours. At one point the bankers are instructed to shut their eyes and visualise themselves filling the room and then the building. They finish up by walking around the room acting out various levels of presence, from low-key to over the top.

C. It's easy to poke fun. Yet similar mental workouts are happening in corporate seminar rooms around the globe. The Mind Gym alone offers some 70 different sessions, including ones on mental stamina, creativity for logical thinkers and 'zoom learning'. Other outfits draw more directly on the exercise analogy, offering 'neurobics' courses with names like 'brain sets' and 'cerebral fitness'. Then there are books with titles like Pumping Ions, full of brainteasers that claim to 'flex your mind', and software packages offering memory and spatial-awareness games.

D. But whatever the style, the companies' sales pitch is invariably the same - follow our routines to shape and sculpt your brain or mind, just as you might tone and train your body. And, of course, they nearly all claim that their mental workouts draw on serious scientific research and thinking into how the brain works.

E. One outfit, Brainergy of Cambridge, Massachusetts (motto: 'Because your grey matter matters') puts it like this: 'Studies have shown that mental exercise can cause changes in brain anatomy and brain chemistry which promote increased mental efficiency and clarity. Neuroscience is cutting-edge.' And on its website, Mind Gym trades on a quote from Susan Greenfield, one of Britain's best known neuroscientists: 'It's a bit like going to the gym, if you exercise your brain it will grow.'

F. Indeed, the Mind Gym originally planned to hold its sessions in a local health club, until its founders realised where the real money was to be made. Modern companies need flexible, bright thinkers and will seize on anything that claims to create them, especially if it looks like a quick fix backed by science. But are neurobic workouts really backed by science? And do we need them?

G. Nor is there anything remotely high-tech about what Lawrence Katz, co-author of Keep Your Brain Alive, recommends. Katz, a neurobiologist at Duke University Medical School in North Carolina, argues that just as many of us fail to get enough physical exercise, so we also lack sufficient mental stimulation to keep our brains in trim. Sure we are busy with jobs, family and housework. But most of this activity is a repetitive routine. And any leisure time is spent slumped in front of the TV.

H. So, read a book upside down. Write or brush your teeth with your wrong hand. Feel your way around the room with your eyes shut. Sniff vanilla essence while listening intently to orchestral music. Anything, says Katz, to break your normal mental routine. It will help invigorate your brain, encouraging its cells to make new connections and pump out neurotrophins, substances that feed and sustain brain circuits.

I. Well, up to a point it will. 'What I'm really talking about is brain maintenance rather than bulking up your IQ,' Katz adds. Neurobics, in other words, is about letting your brain fulfil its potential. It cannot create super-brains. Can it achieve even that much, though? Certainly, the brain is an organ that can adapt to the demands placed on it. Tests on animal brain tissue, for example, have repeatedly shown that electrically stimulating the synapses that connect nerve cells thought to be crucial to learning and reasoning, makes them stronger and more responsive. Brain scans suggest we use a lot more of our grey matter when carrying out new or strange tasks than when we're doing well-rehearsed ones. Rats raised in bright cages with toys sprout more neural connections than rats raised in bare cages - suggesting perhaps that novelty and variety could be crucial to a developing brain. And neurologists have proved time and again that people who lose brain cells suddenly during a stroke often sprout new connections to compensate for the loss - especially if they undergo extensive therapy to overcome any paralysis.

J. Guy Claxton, an educational psychologist at the University of Bristol, dismisses most of the neurological approaches as 'neuro-babble'. Nevertheless, there are specific mental skills we can learn, he contends. Desirable attributes such as creativity, mental flexibility, and even motivation, are not the fixed faculties that most of us think. They are thought habits that can be learned. The problem, says Claxton, is that most of us never get proper training in these skills. We develop our own private set of mental strategies for tackling tasks and never learn anything explicitly. Worse still, because any learned skill - even driving a car or brushing our teeth - quickly sinks out of consciousness, we can no longer see the very thought habits we're relying upon. Our mental tools become invisible to us.

K. Claxton is the academic adviser to the Mind Gym. So not surprisingly, the company espouses his solution - that we must return our thought patterns to a conscious level, becoming aware of the details of how we usually think. Only then can we start to practise better thought patterns, until eventually these become our new habits. Switching metaphors, picture not gym classes, but tennis or football coaching.

L. In practice, the training can seem quite mundane. For example, in one of the eight different creativity workouts offered by the Mind Gym entitled 'creativity for logical thinkers' one of the mental strategies taught is to make a sensible suggestion, then immediately pose its opposite. So, asked to spend five minutes inventing a new pizza, a group soon comes up with no topping, sweet topping, cold topping, price based on time of day, flat-rate prices and so on.

M. Bailey agrees that the trick is simple. But it is surprising how few such tricks people have to call upon when they are suddenly asked to be creative: 'They tend to just label themselves as uncreative, not realising that there are techniques that every creative person employs.' Bailey says the aim is to introduce people to half a dozen or so such strategies in a session so that what at first seems like a dauntingly abstract mental task becomes a set of concrete, learnable behaviours. He admits this is not a shortcut to genius. Neurologically, some people do start with quicker circuits or greater handling capacity. However, with the right kind of training he thinks we can dramatically increase how efficiently we use it.

N. It is hard to prove that the training itself is effective. How do you measure a change in an employee's creativity levels, or memory skills? But staff certainly report feeling that such classes have opened their eyes. So, neurological boosting or psychological training? At the moment you can pay your money and take your choice. Claxton for one believes there is no reason why schools and universities shouldn't spend more time teaching basic thinking skills, rather than trying to stuff heads with facts and hoping that effective thought habits are somehow absorbed by osmosis.