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.
2017届高中英语第1轮总复习 part2 第7讲《情态动词与虚拟语气》新人教版
2017届高考英语一轮复习课时作业24:Unit 4《Making the news》(新人教版必修5陕西专用)
2017年高考英语一轮复习课时作业7:Unit 7《The Sea》(北师大版必修3通用版)
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2017届高三英语语法要点细讲(高考题+模拟) 专题04 名词性从句
2017年高考英语一轮复习课时作业详答28:Module 4《Carnival》(外研版选修5通用)
2017年高考英语一轮复习课时作业5:Unit 5《Rhythm》(北师大版必修2通用版)
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2017届高三英语语法要点细讲(高考题+模拟) 专题01 定语从句
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2017年高考英语一轮复习课时作业详答33:Module 3《Interpersonal Relationships—Friendship》(外研版选修6通用)
2017届高三英语语法要点细讲(高考题+模拟) 专题02 动词的时态及语态
2017届高中英语第1轮总复习 part2 第3讲《代词和it的用法》新人教版
2017年高考英语一轮复习课时作业详答36:Module 6《War and Peace》(外研版选修6通用)
2017届高中英语第1轮总复习 part2 第9讲《定语从句》新人教版
2017年高考英语一轮复习课时作业详答27:Module 3《Adventure in Literature and the Cinema》(外研版选修5通用)
2017届高中英语第1轮总复习 part2 第10讲《状语从句》新人教版
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2017届高考英语一轮复习课时作业25:Unit 5《First aid》(新人教版必修5陕西专用)
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2017届高中英语第1轮总复习 part2 第13讲《情景交际用语》新人教版
2017年高考英语一轮复习课时作业8:Unit 8《Adventure》(北师大版必修3通用版)
2017届高三英语语法要点细讲(高考题+模拟) 专题03 介词及介词短语
2017年高考英语一轮复习课时作业详答32:Module 2《Fantasy Literature》(外研版选修6通用)
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2017届高中英语第1轮总复习 part2 第5讲《介词》新人教版
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2017年高考英语一轮复习课时作业详答31:Module 1《Small Talk》(外研版选修6通用)
2017年高考英语一轮复习课时作业详答26:Module 2《A Job Worth Doing》(外研版选修5通用)