Reading Test 17
Ensuring our future food supply
Climate change and new diseases threaten the limited varieties of seeds we depend on for food. Luckily, we still have many of the seeds used in the past—but we must take steps to save them.
Six miles outside the town of Decorah, Iowa in the USA, an 890-acre stretch of rolling fields and woods called Heritage Farm is letting its crops go to seed. Everything about Heritage Farm is in sharp contrast to the surrounding acres of intensively farmed fields of corn and soybean that are typical of modern agriculture. Heritage Farm is devoted to collecting rather than growing seeds. It is home to the Seed Savers Exchange, one of the largest non-government-owned seed banks in the United States.
In 1975 Diane Ott Whealy was given the seedlings of two plant varieties that her great grandfather had brought to America from Bavaria in 1870: Grandpa Ott’s morning glory and his German Pink tomato. Wanting to preserve similar traditional varieties, known as heirloom plants, Diane and her husband, Kent, decided to establish a place where the seeds of the past could be kept and traded. The exchange now has more than 13,000 members, and the many thousands of heirloom varieties they have donated are kept in its walk-in coolers, freezers, and root cellars. The seeds of many thousands of heirloom varieties and, as you walk around, an old red barn that is covered in Grandpa Ott’s beautiful morning glory blossoms, you come across the different vegetables, herbs, and flowers they have planted there.
“Each year our members list their seeds in this,” Diane Ott Whealy says, handing over a copy of the Seed Savers Exchange 2010 Yearbook. It is as thick as a big-city telephone directory, with page after page of exotic beans, garlic, potatoes, peppers, apples, pears, and plums—each with its own name and personal history. For example, there’s an Estonian Yellow Cherry tomato, which was brought to the seed bank by “an elderly Russian lady” who lived in Tallinn, and a Persian Star garlic from “a bazaar in Samarkand.” There is also a bean donated by archaeologists searching for pygmy elephant fossils in New Mexico.
Heirloom vegetables have become fashionable in the United States and Europe over the past decade, prized by a food movement that emphasizes eating locally and preserving the flavor and uniqueness of heirloom varieties. Found mostly in farmers’ markets and boutique groceries, heirloom varieties have been squeezed out of supermarkets in favor of modern single-variety fruits and vegetables bred to ship well and have a uniform appearance, not to enhance flavor. But the movement to preserve heirloom varieties goes beyond the current interest in North America and Europe in tasty, locally grown food. It’s also a campaign to protect the world’s future food supply. Most people in the well-fed world give little thought to where their food comes from or how it’s grown. They wander through well-stocked supermarkets without realizing that there may be problems ahead. We’ve been hearing for some time about the loss of flora and fauna in rainforests. Very little, by contrast, is being said or done about the parallel decline in the diversity of the foods we eat.
Food variety extinction is happening all over the world—and it’s happening fast. In the United States, an estimated 90 percent of the historic fruit and vegetable varieties have disappeared. In China, of the 7,000 different apple varieties that were grown in the 1800s, fewer than a hundred remain. In the Philippines, thousands of rice varieties once grown and eaten are no longer cultivated. Experts estimate that in total we have lost more than 50 percent of the world’s food varieties over the past century.
Why is this a problem? Because if disease or future climate change affects one of the handful of plants we’ve let become the dominant source of food, we may desperately need one of those varieties that we have let become extinct or discarded. The loss of the world’s cereal diversity is a particular cause for concern: a fungus called Ug99, which was first identified in Uganda in 1999, is spreading across the world’s crops. From Uganda it moved to Kenya, Ethiopia, Sudan, and Yemen. By 2007 it had jumped the Persian Gulf into Iran. Scientists predict that the fungus will soon make its way into India and Pakistan, then spread to Russia and China, and eventually the USA.
Roughly 90 percent of the world’s wheat has no defense against this particular fungus. If it reached the USA, an estimated one billion dollars’ worth of crops would be at risk. Scientists believe that in Asia and Africa alone, the portion currently in danger could leave one billion people without their primary food source. A famine with significant humanitarian consequences could follow, according to Rick Ward of Cornell University.
The population of the world is expected to reach nine billion by 2045. Some experts say we’ll need to double our food production to keep up with this growth. Given the added challenge of climate change and disease, it is becoming even more urgent to find ways to increase food yield. The world has become increasingly dependent upon a technology-driven, one-size-fits-all approach to food supply. Yet the best hope for securing our food’s future may depend on our ability to preserve the locally cultivated foods of the past.
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Australian parrots and their adaptation to habitat change
A.
Parrots are found across the tropics and in all southern hemisphere continents except Antarctica, but nowhere do they display such a richness of diversity and form as in Australia. One-sixth of the world’s 345 parrot species are found there, and Australia has long been renowned for the number and variety of its parrots.
B.
In the 16th century, the German cartographer Mercator made a world map that included a place, somewhere near present-day Australia, that he named Terra Psittacorum – the Land of Parrots – and the first European settlers in Australia often referred to the country as Parrot Land. In 1865, the celebrated British naturalist and wildlife artist John Gould said: “No group of birds gives Australia so tropical and benign an air as the numerous species of this great family by which it is tenanted.”
C.
Parrots are descendants of an ancient line. Due to their great diversity, and since most species inhabit Africa, Australia and South America, it seems almost certain that parrots originated millions of years ago on the ancient southern continent of Gondwana, before it broke up into the separate southern hemisphere continents we know today. Much of Gondwana comprised vast rainforests intersected by huge slow-flowing rivers and expansive lakes, but by eight million years ago, great changes were underway. The center of the continent of Australia had begun to dry out, and the rainforest that once covered it gradually contracted to the continental margins, where, to a limited extent, they still exist today.
D.
The creatures that remained in those shrinking rainforests had to adapt to the drier conditions or face extinction. Reacting to these desperate circumstances, the parrot family, typically found in jungles in other parts of the world, has populated some of Australia’s harshest environments. The parrots spread from ancestral forests through eucalypt woodlands to colonies in the central deserts of Australia, and as a consequence they diversified into a wide range of species with adaptations that reflect the many changes animals and plants had to make to survive in these areas.
E.
These evolutionary pressures helped mould keratin, the substance from which breaks are made, into a range of tools capable of gathering the new food types favored by various species of parrot. The size of a parrot’s short, blunt beak and the length of that beak’s upper curved section are related to the type of food each species eats. Some have comparatively long beaks that are perfect for extracting seeds from fruit; others have broader and stronger beaks that are designed for cracking hard seeds.
F.
Differently shaped beaks are not the only adaptations that have been made during the developing relationship between parrots and their food plants. Like all of Australia’s many honey-eating birds, the rainbow-coloured lorikeets and the flowers on which they feed have long co-evolved with features such as the shape and colour of the flowers adapted to the bird’s particular needs, and physical appearance, so it is the most attractive to birds, and thus flowers dependent on birds for pollination are more often fed on, and lorikeets’ tongues have bristled tips which help them to collect as much pollen as possible.
G.
Today, most of Australia’s parrots inhabit woodland and open forest, and their movements are directed towards both deserts and wetter areas. The majority are nomadic to some degree, moving around to take advantage of feeding and water resources. The red-tailed black cockatoo, the galah, the corella, the cockatiel, the budgerigar and the masked lovebird have expanded their ranges in recent years. They are among the species that have adapted well to the changes brought about by European settlement: forest felling created grasslands where galahs and corellas thrive.
H.
But other parrot species did not fare so well when their environments were altered. The clearing of large areas of rainforest is probably responsible for the disappearance of the double-eyed fig parrot, and numbers of ground parrots declined when a great part of their habitat was destroyed by the draining of coastal swamps. Even some parrot species that benefited from forest clearing at first are now confronted by a shortage of nesting sites due to further man-made changes.
I.
New conditions also sometimes favour an incoming species over one that originally inhabited the area. For example, after farmers cleared large areas of forest on Kangaroo Island off the coast of South Australia, the island was colonised by galahs. They were soon going down holes and destroying black cockatoo eggs in order to take the hole for their own use. Their success precipitated a partial collapse in the black cockatoo population when the latter lost the struggle for scarce nesting hollows.
J.
There may be no final answer to ensuring an equitable balance between parrot species. Nest box programmers help ease the shortage of nesting sites in some places, but there are not enough, they are expensive and they are not an adequate substitute for large, old trees, such as the habitat they represent and nectar, pollen and seeds they provide. Competition between parrots for nest sites is a result of the changes we humans have made to the Earth. We are the most widespread and dangerous competitors that parrots have ever had to face, but we also have the knowledge and skill to maintain the wonderfully rich diversity of Australia’s parrots. All we need is the will to do so.
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When people are deaf’ to music
Music has long been considered a uniquely human concept. In fact, most psychologists agree that music is a universal human instinct. Like any ability, however, there is great variation in people’s musical competence. For every brilliant pianist in the world, there are several people we refer to as “tone deaf”. It is not simply that people with tone deafness (or amusia) are unable to sing in tune; they are also unable to discriminate between tones or recognize familiar melodies. Such a “disorder” can occur either due to brain damage, but recent research has been undertaken in an attempt to discover the cause of congenital amusia (when people are born with the condition), which is not associated with any brain damage, hearing problems, or lack of exposure to music.
According to the research of Dr. Isabelle Peretz of the University of Montreal, amusia is more complicated than the inability to distinguish pitches. An amusic (a person who has the condition of amusia) can distinguish between two pitches that are far apart, but cannot tell the difference between intervals smaller than a half step on the Western diatonic scale, while most people can easily distinguish differences smaller than that. When listening to melodies which have had a single note altered so that it is out of key with the rest of the melody, they often do not notice a problem. As would be expected, amusics perform significantly worse at singing and tapping a rhythm along with a melody than do non-amusics.
The most fascinating aspect of amusia is how specific it is. Because of music’s close ties to language, it might be expected that a musical impairment may be caused by a language impairment. Studies suggest, however, that language and music ability are independent of one another. People with brain damage in areas critical to language are often still able to sing, despite being unable to communicate through speech. Moreover, while amusics show deficiencies in their recognition of pitch differences in melodies, they show no impairment in tonal languages, such as Chinese, nor do they report having any difficulty discriminating between words that differ only in their intonation. The linguistic cues inherent in speech make discrimination of meaning much easier for amusics. Amusics are also successful most of the time at detecting the mood of a melody, can identify a speaker based on his or her voice, and can discriminate and identify environmental sounds.
Recent work has been focused on locating the part of the brain that is responsible for amusia. The temporal lobes of the brain, the location of the primary auditory cortex, have been considered. It has long been believed that the temporal lobes, especially the right temporal lobe, are most active when listening, so any musical disability should logically stem from here as well. Because it has been shown that there is no hearing deficit in amusia, researchers moved on to the temporal neocortex, which is where more sophisticated processing of musical cues was thought to take place. New studies, however, have indicated that deficits in amusics are located outside the auditory cortex. Brain scans of amusics do not show any reaction at all to differences smaller than half a step, whereas in tones one large, their brains react, showing twice as much activity on the right side of the brain as a normal brain would—often at the same time. These differences do not occur in the auditory cortex, indicating again that the deficits of amusia lie mostly in higher processing of melodies.
So what does this all mean? Looking only at the research of Peretz in the field of neuropsychology of music, it would appear that amusia is some sort of disorder. As a student of neurobiology, however, I am skeptical. Certainly the studies by Peretz that have found significant differences between the brains of so-called amusics and normal brains are legitimate. The more important question now becomes one of normality. Every trait from skin color to intelligence to mood exists on a continuum—there is a great idea of variation from one extreme to the other. Just because we recognize that basic musical ability is something that the vast majority of people have, this doesn’t mean that the lack of it is abnormal.
What makes an amusic worse off than a musical prodigy? Musical ability is culturally valued and may have been a factor in survival at one point in human history, but it does not seem likely that it is being selected for on an evolutionary scale any longer. Darwin believed that music was adaptive as a way of finding a mate, but who needs to be able to sing to find a partner in an age when it is possible to express your emotions through a song on your iPod?
While the idea of amusia is interesting, it seems to be just one end of the continuum of innate musical ability. Comparing this “disorder” to learning disorders like specific language impairment seems to be going too far. Before amusia can be declared a disability, further research must be done to determine whether lack of musical ability is actually detrimental in any way. If no disadvantages can be found of having amusia, then it is no more a disability than having poor fashion sense or bad handwriting.
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