1663 본문읽기 10
카테고리 없음2023. 5. 22. 14:57
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1663-23
Savannas pose a bit of a problem for ecologists. There is an axiom in ecology that 'complete competitors cannot coexist': in other words, where two populations of organisms use exactly the same resources, one would be expected to do so slightly more efficiently than the other and therefore come to dominate in the long term. In temperate parts of the world, either trees dominate (in forests) or grasses dominate (in grasslands). Yet, in savannas grasses and trees coexist. The classic explanation proposes that trees have deep roots while grasses have shallow roots. The two plant types are therefore able to coexist because they are not in fact competitors: the trees increase in wetter climates and on sandier soils because more water is able to penetrate to the deep roots. Trees do indeed have a few small roots which penetrate to great depth, but most of their roots are in the top half-metre of the soil, just where the grass roots are.
1663-25
Sequoyah, a Cherokee Indian, was born in about 1770 in Taskigi, now in Tennessee. Raised by his Cherokee mother, the young Sequoyah never learned to read or write English. While interacting with English speakers, he realized the necessity of a writing system for the Cherokee people. In about 1809, Sequoyah began developing a system of writing, adapting letters from English, Greek, and Hebrew. By 1821, he had created a system of 86 symbols, representing all the syllables of the Cherokee language. The Cherokee people began to use the system in their schools and publish books and newspapers in their language. In 1824, the General Council of the Eastern Cherokees awarded Sequoyah a medal in honor of his accomplishment. Sequoyah moved to Oklahoma some years later and died in what is now Texas in 1843. And later, people remembered him by naming a certain tree species "Sequoia."
1663-28
If an animal is innately programmed for some type of behaviour, then there are likely to be biological clues. It is no accident that fish have bodies which are streamlined and smooth, with fins and a powerful tail. Their bodies are structurally adapted for moving fast through the water. Similarly, if you found a dead bird or mosquito, you could guess by looking at its wings that flying was its normal mode of transport. However, we must not be over-optimistic. Biological clues are not essential. The extent to which they are found varies from animal to animal and from activity to activity. For example, it is impossible to guess from their bodies that birds make nests, and, sometimes, animals behave in a way quite contrary to what might be expected from their physical form: ghost spiders have tremendously long legs, yet they weave webs out of very short threads. To a human observer, their legs seem a great hindrance as they spin and move about the web.
1663-29
In 2001, researchers at Wayne State University asked a group of college volunteers to exercise for twenty minutes at a self-selected pace on each of three machines: a treadmill, a stationary bike, and a stair climber. Measurements of heart rate, oxygen consumption, and perceived effort were taken throughout all three workouts. The researchers expected to find that the subjects unconsciously targeted the same relative physiological intensity in each activity. Perhaps they would automatically exercise at 65 percent of their maximum heart rate regardless of which machine they were using. Or maybe they would instinctively settle into rhythm at 70 percent of their maximum rate of oxygen consumption in all three workouts. But that's not what happened. There was, in fact, no consistency in measurements of heart rate and oxygen consumption across the three disciplines. Instead, the subjects were found to have chosen the same level of perceived effort on the treadmill, the bike, and the stair climber.
1663-30
In the summer of 1972, the actor Anthony Hopkins was signed to play a leading role in a film based on George Feifer's novel The Girl from Petrovka. That is why he traveled to London to buy a copy of the book. Unfortunately, none of the main London bookstores had a copy. Then, on his way home, waiting for an underground train at Leicester Square tube station, he saw a discarded book lying on the seat next to him. It was a copy of The Girl from Petrovka. As if that was not coincidence enough, more was to follow. Later, when he had a chance to meet the author, Hopkins told him about this strange occurrence. Feifer was interested. He said to him that in November 1971 he had lent a friend a copy of the book—a unique copy in which he had made notes on turning the British English into American English for the publication of an American version—but his friend had lost the copy in London. A quick check of the copy Hopkins had found showed that it was the very same copy that his friend had mislaid.
Savannas pose a bit of a problem for ecologists. There is an axiom in ecology that 'complete competitors cannot coexist': in other words, where two populations of organisms use exactly the same resources, one would be expected to do so slightly more efficiently than the other and therefore come to dominate in the long term. In temperate parts of the world, either trees dominate (in forests) or grasses dominate (in grasslands). Yet, in savannas grasses and trees coexist. The classic explanation proposes that trees have deep roots while grasses have shallow roots. The two plant types are therefore able to coexist because they are not in fact competitors: the trees increase in wetter climates and on sandier soils because more water is able to penetrate to the deep roots. Trees do indeed have a few small roots which penetrate to great depth, but most of their roots are in the top half-metre of the soil, just where the grass roots are.
1663-25
Sequoyah, a Cherokee Indian, was born in about 1770 in Taskigi, now in Tennessee. Raised by his Cherokee mother, the young Sequoyah never learned to read or write English. While interacting with English speakers, he realized the necessity of a writing system for the Cherokee people. In about 1809, Sequoyah began developing a system of writing, adapting letters from English, Greek, and Hebrew. By 1821, he had created a system of 86 symbols, representing all the syllables of the Cherokee language. The Cherokee people began to use the system in their schools and publish books and newspapers in their language. In 1824, the General Council of the Eastern Cherokees awarded Sequoyah a medal in honor of his accomplishment. Sequoyah moved to Oklahoma some years later and died in what is now Texas in 1843. And later, people remembered him by naming a certain tree species "Sequoia."
1663-28
If an animal is innately programmed for some type of behaviour, then there are likely to be biological clues. It is no accident that fish have bodies which are streamlined and smooth, with fins and a powerful tail. Their bodies are structurally adapted for moving fast through the water. Similarly, if you found a dead bird or mosquito, you could guess by looking at its wings that flying was its normal mode of transport. However, we must not be over-optimistic. Biological clues are not essential. The extent to which they are found varies from animal to animal and from activity to activity. For example, it is impossible to guess from their bodies that birds make nests, and, sometimes, animals behave in a way quite contrary to what might be expected from their physical form: ghost spiders have tremendously long legs, yet they weave webs out of very short threads. To a human observer, their legs seem a great hindrance as they spin and move about the web.
1663-29
In 2001, researchers at Wayne State University asked a group of college volunteers to exercise for twenty minutes at a self-selected pace on each of three machines: a treadmill, a stationary bike, and a stair climber. Measurements of heart rate, oxygen consumption, and perceived effort were taken throughout all three workouts. The researchers expected to find that the subjects unconsciously targeted the same relative physiological intensity in each activity. Perhaps they would automatically exercise at 65 percent of their maximum heart rate regardless of which machine they were using. Or maybe they would instinctively settle into rhythm at 70 percent of their maximum rate of oxygen consumption in all three workouts. But that's not what happened. There was, in fact, no consistency in measurements of heart rate and oxygen consumption across the three disciplines. Instead, the subjects were found to have chosen the same level of perceived effort on the treadmill, the bike, and the stair climber.
1663-30
In the summer of 1972, the actor Anthony Hopkins was signed to play a leading role in a film based on George Feifer's novel The Girl from Petrovka. That is why he traveled to London to buy a copy of the book. Unfortunately, none of the main London bookstores had a copy. Then, on his way home, waiting for an underground train at Leicester Square tube station, he saw a discarded book lying on the seat next to him. It was a copy of The Girl from Petrovka. As if that was not coincidence enough, more was to follow. Later, when he had a chance to meet the author, Hopkins told him about this strange occurrence. Feifer was interested. He said to him that in November 1971 he had lent a friend a copy of the book—a unique copy in which he had made notes on turning the British English into American English for the publication of an American version—but his friend had lost the copy in London. A quick check of the copy Hopkins had found showed that it was the very same copy that his friend had mislaid.
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