4. Native Americans
5. prescribed burns
12. NOT GIVEN
可参考真题：C5T4P2：Flawed Beauty: the problem with toughened glass
The Forgotten Forest
Found only in the Deep South of America, long leaf pine woodlands have dwindled to about 3 percent of their former range, but new efforts are under way to restore them.
THE BEAUTY AND THE BIODIVERSITY of the longleaf pine forest are well-kept secrets, even in its native South. Yet it is among the richest ecosystems in North America, rivaling tallgrass prairies and the ancient forests of the Pacific Northwest in the number of species it shelters. And like those two other disappearing wildlife habitats, longleaf is also critically endangered.
In longleaf pine forests, trees grow widely scattered, creating an open, parklike environment, more like a savanna than a forest. The trees are not so dense as to block the sun. This openness creates a forest floor that is among the most diverse in the world, where plants such as many-flowered grass pinks, trumpet pitcher plants, Venus flytraps, lavender ladies and pineland bog-buttons grow. As many as 50 different species of wild flowers, shrubs, grasses and ferns have been cataloged in just a single square meter.
Once, nearly 92 million acres of longleaf forest flourished from Virginia to Texas, the only place in the world where it is found. By the turn of the 21st century, however, virtually all of it had been logged, paved or farmed into oblivion. Only about 3 percent of the original range still supports longleaf forest, and only about 10,000 acres of that is uncut old-growth-the rest is forest that has regrown after cutting. An estimated 100,000 of those acres are still vanishing every year. However, a quiet movement to reverse this trend is rippling across the region. Governments, private organisations (including NWF) and individual conservationists are looking for ways to protect and preserve the remaining longleaf and to plant new forests for future generations.
Figuring out how to bring back the piney woods also will allow biologists to help the plants and animals that depend on this habitat. Nearly two-thirds of the declining, threatened or endangered species in the southeastern United States are associated with longleaf. The outright destruction of longleaf is only part of their story, says Mark Danaher, the biologist for South Carolina’s Francis Marion National Forest. He says the demise of these animals and plants also is tied to a lack of fire, which once swept through the southern forests on a regular basis.”Fire is absolutely critical for this ecosystem and for the species that depend on it,”says Danaher.
Name just about any species that occurs in longleaf and you can find a connection to fire. Bach-man’s sparrow is a secretive bird with a beautiful song that echoes across the longleaf flat woods. It tucks its nest on the ground beneath clumps of wiregrass and little bluestem in the open under story, But once fire has been absent for several years, and a tangle of shrubs starts to grow, the sparrows disappear. Gopher tortoises, the only native land tortoises east of the Mississippi, are also abundant in longleaf. A keystone species for these forests, its burrows provide homes and safety to more than 300 species of vertebrates and invertebrates ranging from eastern diamondback rattlesnakes to gopher frogs, If fire is suppressed, however, the tortoises are choked out.”If we lose fire,”says Bob Mitchell, an ecologist at the Jones Center,”we lose wildlife.”
Without fire, we also lose longleaf. Fire knocks back the oaks and other woods that can grow up to overwhelm longleaf forests. They are fire forests,”Mitchell says: They evolved in the lightning capital of the eastern United States.”And it wasn’t only lightning strikes that set the forest aflame.”Native Americans also lit fires to keep the forest open,”Mitchell says.”So did the early pioneers. They helped create the longleaf pine forests that we know today.”
Fire also changes how nutrients flow throughout longleaf ecosystems, in ways we are just beginning to understand. For example, researchers have discovered that frequent fires provide extra calcium, which is critical for egg production, to endangered red-cockaded woodpeckers. Frances James, a retired avian ecologist from Florida State University, has studied these small black-and-white birds for more than two decades in Florida’s sprawling Apalachicola National Forest. When she realised female woodpeckers laid larger clutches in the first breeding season after their territories were burned, she and her colleagues went searching for answers.”We learned calcium is stashed away in woody shrubs when the forest is not burned,”James says.“But when there is a fire, a pulse of calcium moves down into the soil and up into the longleaf.”Eventually, this calcium makes its way up the food chain to a tree-dwelling species of ant, which is the red-cockaded’s favorite food. The result: more calcium for the birds, which leads to more eggs, more young and more woodpeckers.
Today, fire is used as a vital management tool for preserving both longleaf and its wildlife. Most of these fires are prescribed burns, deliberately set with a drip torch. Although the public often opposes any type of fire-and the smoke that goes with it-these frequent, low-intensity burns reduce the risk of catastrophic conflagrations.”Forests are going to burn,”says Amadou Diop, NWF’s southern forests restoration manager.”Il’s just a question of when. With prescribed burns, we can pick the time and the place.”
Diop is spearheading a new NWF effort to restore longleaf.”It’s a species we need to go back to, he says. Educating landowners about the advantages of growing longleaf is part of the program, he adds, which will soon be under way in nine southern states.”Right now, most longleaf is on public land,”says Jerry McCollum, president of the Georgia Wildlife Federation.”Private land is where we need to work,”he adds, pointing out that more than 90 percent of the acreage within the historic range of longleaf falls under this category.
Interest among private landowners is growing throughout the South, but restoring longleaf is not an easy task. The herbaceous layer-the understory of wiregrasses and other plants-also needs to be re-created. In areas where the land has not been chewed up by farming, but con-verted to loblolly or slash pine plantations, the seed bank of the longleaf forest usually remains viable beneath the soil. In time, this original vegetation can be coaxed back. Where agriculture has destroyed the seeds, however, wiregrass must be replanted. Right now, the expense is prohibitive, but researchers are searching for low-cost solutions.
Bringing back longleaf is not for the short-sighted, however. Few of us will be alive when the pines being planted today become mature forests in 70 to 80 years. But that is not stopping longleaf enthusiasts,”Today, it’s getting hard to find longleaf seedlings to buy,”one of the private landowners says.”Everyone wants them. Longleaf is in a resurgence.”
可参考真题：C12T5P3：What’s the purpose of gaining knowledge?
文章题目：What do babies know?(婴儿知道什么?)
28. NOT GIVEN
30. NOT GIVEN
可参考真题：C10T2P2：Gifted children and learning
What Do Babies Know?
A As Daniel Haworth is settled into a high chair and wheeled behind a black screen, a sudden look of worry furrows his 9-month-old brow. His dark blue eyes dart left and right in search of the familiar reassurance of his mother's face. She calls his name and makes soothing noises, but Daniel senses something unusual is happening. He sucks his fingers for comfort, but, finding no solace, his month crumples, his body stiffens, and he lets rip an almighty shriek of distress. This is the usual expression when babies are left alone or abandoned. Mom picks him up, reassures him, and two minutes later, a chortling and alert Daniel returns to the darkened booth behind the screen and submits himself to baby lab, a unit set up in 2005 at the University of Manchester in northwest England to investigate how babies think.
B Watching infants piece life together, seeing their senses, emotions and motor skills take shape, is a source of mystery and endless fascination-at least to parents and developmental psychologist. We can decode their signals of distress or read a million messages into their first smile. But how much do we really know about what's going on behind those wide, innocent eyes? How much of their understanding of and response to the world comes preloaded at birth? How much
is built from scratch by experience? Such are the questions being explored at baby lab. Though the facility is just 18 months old and has tested only 100 infants, it's already challenging current thinking on what babies know and how they come to know it.
C Daniel is now engrossed in watching video clips of a red toy train on a circular track. The train disappears into a tunnel and emerges on the other side. A hidden device above the screen is tracking Daniel's eyes as they follow the train and measuring the diametre of his pupils 50 times a second. As the child gets bored-or ”habituated”, as psychologists call the process-his attention level steadily drops. But it picks up a little whenever some novelty is introduced. The train might be green, or it might be blue. And sometimes an impossible thing happens-the train goes into the tunnel one color and comes out another.
D Variations of experiments like this one, examining infant attention, have been a standard tool of developmental psychology ever since the Swiss pioneer of the field, Jean Piaget ,started experimenting on his children in the 1920s.Piaget's work led him to conclude that infants younger than 9 months have no innate knowledge of how the world works or any sense of "object permanence"(that people and things still exist even when they're not seen). Instead, babies must gradually construct this knowledge from experience. Piaget's "constructivist" theories were massively influential on postwar educators and psychologist, but over the past 20 years or
so they have been largely set aside by a new generation of "nativist" psychologists and cognitive scientists whose more sophisticated experiments led them to theorise that infants arrive already equipped with some knowledge of the physical world and even rudimentary programming for math and language. Baby lab director Sylvain Sirois has been putting these smart-baby theories through a rigorous set of tests. His conclusions so far tend to be more Piagetian:“Babies" he says, "know nothing."
E What Sirois and his postgraduate assistant Lain Jackson are challenging is the interpretation of a variety of classic experiments begun in the mid-1980s in which babies were shown physical events that appeared to violate such basic concepts as gravity, solidity and contiguity. In one such experiment, by University of Illinois psychologist Renee Baillargeon, a hinged wooden panel appeared to pass right through a box. Baillargeon and M.I.T's Elizabeth Spelke found that babies as young as 31/2 months would reliably look longer at the impossible event than at the
normal one. Their conclusion: babies have enough built-in knowledge to recognize that some-thing is wrong.
F Sirois does not take issue with the way these experiments were conducted. "The methods are correct and replicable," he says, "it's the interpretation that's the problem." In a critical review to be published in the forthcoming issue of the European Journal of Developmental Psychology, he and Jackson pour cold water over recent experiments that claim to have observed innate or precocious social cognition skills in infants. His own experiments indicate that a baby's fascination with physically impossible events merely reflects a response to stimuli that are novel. Data from the eye tracker and the measurement of the pupils(which widen in response to arousal or interest show that impossible events involving familiar objects are no more interesting than possible events involving novel objects. In other words, when Daniel had seen the red train come out of the tunnel green a few times, he gets as bored as when it stays the same color. The mistake of previous research, says Sirois, has been to leap to the conclusion that infants can understand the concept of impossibility from the mere fact that they are able to perceive some novelty in it. ”The real explanation is boring," he says.
G So how do babies bridge the gap between knowing squat and drawing triangles-a task Daniel's sister Lois,21/2, is happily tackling as she waits for her brother? "Babies have to learn everything, but as Piaget was saying, they start with a few primitive reflexes that get things going," said Sirois. For example, hardwired in the brain is an instinct that draws a baby's eyes to a human face. From brain imaging studies we also know that the brain has some sort of visual buffer that continues to represent objects after they have been removed-a lingering perception rather than conceptual understanding. So when babies encounter novel or unexpected events, Sirois explains, "there's a mismatch between the buffer and the information they're getting at that moment. And what you do when you've got a mismatch is you try to clear the buffer. And that takes attention." So learning, says Sirois, is essentially the laborious business of resolving mismatches. "The thing is, you can do a lot of it with this wet sticky thing called a brain. It's a fantastic, statistical-learning machine". Daniel, exams ended, picks up a plastic tiger and, chewing thoughtfully upon its heat, smiles as if to agree.
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