背诵篇章 Botany, the study of plants, occupies a peculiar position in the history of human knowledge. For many thousands of years it was the one field of awareness about which humans had anything more than the vaguest of insights. It is impossible to know today just what our Stone Age ancestors knew about plants, but form what we can observe of pre-industrial societies that still exist a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things even for other plants. They have always been enormously important to the welfare of people not only for food, but also for clothing, weapons, tools, dyes, medicines, shelter, and a great many other purposes. Tribes living today in the jungles of the Amazon recognize literally hundreds of plants and know many properties of each. To them, botany, as such, has no name and is probably not even recognized as a special branch of" knowledge at all Unfortunately, the more industrialized we become the farther away we move from direct contact with plants, and the less unconsciously e, an apple, or an orchid. When our Neolithic ancestors, living in the Middle East about L0, 000 years ago, discovered that certain grasses could be harvested and their seeds plan ted for richer yields the next season the first great step in a new association of plants and humans was taken Grains were discovered and from them flowed the marvel of agriculture: cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a littile there from many varieties that grew wild-and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away ton浮游生物/' punkt Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carl es each yea, the seas plankton gener more than twice as much Despite its enormous food potential, little effect was made until recently to farm plankto ve farm grasses on land. Nov marine scientists have at last begun to study this possbility, especially as the seas resources loom even more important as a means of feeding an expanding world population. No one yet has seriously suggested that"plankton-burgers" may soon become popular around the world. As a possible farmed pplementary food source, however, plankton is gaining considerable interest among marine scientists One type of plankton that seems to have great harvest possibilities is a tiny shrimp-like creature called krill. Growing to two or three inches long krill provides the major food for the great blue whale, the largest animal to ever inhabit the Earth. Real izing that this whale may grow to 100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily. In the oysters were raised in much the same way as dirt farmers raised tomatoes-by transplanting them. First, far mers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about. Next, they "planted fertilized oyster eggs, which within two or three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on the bottom. There they remained and in time grew into baby oysters called seed or spat The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long, farmers gathered the baby oysters, transplanted them once more into another body of water to fatten them ntil recently the supply of wild oysters and farmed were more than enough to satisfy peoples needs. But today the delectable seafood is no longer available in abundance. the problem has become so serious that some oyster beds have背 诵 篇 章 14 32 Botany Botany, the study of plants, occupies a peculiar position in the history of human knowledge. For many thousands of years it was the one field of awareness about which humans had anything more than the vaguest of insights. It is impossible to know today just what our Stone Age ancestors knew about plants, but form what we can observe of pre-industrial societies that still exist a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things even for other plants. They have always been enormously important to the welfare of people not only for food, but also for clothing, weapons, tools, dyes, medicines, shelter, and a great many other purposes. Tribes living today in the jungles of the Amazon recognize literally hundreds of plants and know many properties of each. To them, botany, as such, has no name and is probably not even recognized as a special branch of “ knowledge” at all. Unfortunately, the more industrialized we become the farther away we move from direct contact with plants, and the less distinct our knowledge of botany grows. Yet everyone comes unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize a rose, an apple, or an orchid. When our Neolithic ancestors, living in the Middle East about 10,000 years ago, discovered that certain grasses could be harvested and their seeds planted for richer yields the next season the first great step in a new association of plants and humans was taken. Grains were discovered and from them flowed the marvel of agriculture: cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a little there from many varieties that grew wild - and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away. 33 Plankton 浮游生物. / 'plжηktэn; `plжηktэn/ Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals. Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the sea’s plankton generates more than twice as much. Despite its enormous food potential, little effect was made until recently to farm plankton as we farm grasses on land. Now marine scientists have at last begun to study this possibility, especially as the sea’s resources loom even more important as a means of feeding an expanding world population. No one yet has seriously suggested that “ plankton-burgers” may soon become popular around the world. As a possible farmed supplementary food source, however, plankton is gaining considerable interest among marine scientists. One type of plankton that seems to have great harvest possibilities is a tiny shrimp-like creature called krill. Growing to two or three inches long, krill provides the major food for the great blue whale, the largest animal to ever inhabit the Earth. Real izing that this whale may grow to 100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily. 34 Raising Oysters In the oysters were raised in much the same way as dirt farmers raised tomatoes - by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about. Next, they ”planted” fertilized oyster eggs, which within two or three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on the bottom. There they remained and in time grew into baby oysters called seed or spat. The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long, farmers gathered the baby oysters, transplanted them once more into another body of water to fatten them up. Until recently the supply of wild oysters and those crudely farmed were more than enough to satisfy people’s needs. But today the delectable seafood is no longer available in abundance. The problem has become so serious that some oyster beds have