高中英语人教版必修第三册07

[00:06.35]READING

[00:07.58]THE BIRTH OF A SCIENCE

[00:10.19]Before the eighteenth century, botany was merely a branch of medicine.

[00:13.90]Unit then, mostly doctors and surgeons studied herbs.

[00:17.97]Attempts had been made by others to classify 1 plant species 2 into groups,

[00:21.81]but the breakthrough came with the work of Carl Linnaeus.

[00:24.56]Showing how plants were related 3 was a complex and strange thing before Linnaeus developed his system.

[00:29.96]The idea to give each species two names was not new, but names were not truly fixed 4 and accepted.

[00:35.89]Some scientists classified 5 plants into herbs and trees,

[00:39.65]or according to the shape of the fruit, or whether they had flowers or not.

[00:43.10]But Linnaeus’ idea of grouping plants in families was unique.

[00:47.28]In his system the identification 6 of different species was based on the arrangement of the male and female 7 organs in the flowers.

[00:54.65]As a result, fruits such as peaches and pears are in fact related, although they are different at first sight.

[01:01.31]Linnaeus’ system soon conquered 8 the world.

[01:04.42]In 1759, Linnaeus’ student, Daniel Solander, traveled to England to promote the new system.

[01:10.11]In London, Solander developed a lifelong friendship with Joseph Banks,

[01:09.11]who would late ask him to join his team of botanical explorers on the Endeavour in 1768.

[01:14.76]Born into a life of privilege 9, Joseph Banks was the son of wealthy family.

[01:18.96]When his father died in 1761, Banks was only eighteen years old.

[01:23.53]Many young men in his position would lead a cosy 10 life, but young Banks had an appetite for knowledge.

[01:28.81]Despite his wealth, he worked to make a career in science.

[01:32.60]He made a first journey to study wild plants in 1766.

[01:36.54]His next expedition was the great voyage with James Cook to Oceania.

[01:35.54]In 1768, the Royal Navy 11 appointed James Cook as the commander of the Endeavour to take members of the Royal Society on an expedition to Tahiti.

[01:44.66]According to the instructions given to Captain Cook,

[01:47.35]the expedition had three goals.

[01:48.89]The primary goal was to study the passing of the planet 12 Venus across the sun.

[01:53.23]This would give astronomers 13 a change to calculate 14 the distance between the earth and the sun.

[01:57.61]Secondly the purpose of the expedition was to record, classify and describe all plant and animal life observed during the trip.

[02:01.14]Thirdly, Captain Cook received secret instructions to search for an unknown southern continent.

[02:06.55]As astronomy 15 was one of the most important branches of science,

[02:10.57]it was the British government that paid for all the equipment and expenses for that of the expedition.

[02:14.94]Since the government would not pay for such a new field of science as botany, Joseph Banks,

[02:20.11]at the age of 25, had to supply about￡10,000 of his own money to equip the expedition.

[02:25.85]On their three-year voyage, Joseph Banks did not only study and describe new plants he found,

[02:43.36]but also looked out new economic species: plans that could be grown in England or other parts of the world to produce crops that could be sold.

[02:50.96]Banks was the first to move crops from one continent to another on a large scale,

[02:55.66]helping to develop local economies with these new imports.

[02:58.85]Some plants that were spread over the globe in this way include cocoa, hemp 16 and tea.

[03:03.97]The Endeavour, returned to England in 1771.

[03:07.42]The voyage had been a great success.

[03:09.56]Wonderful discoveries had been made of strange new lands, cultures, animals and plants.

[03:14.26]After that Captain Cook made two more voyages around the world, but Joseph Banks never undertook another.

[03:20.08]From behind his desk, however, he was involved in enterprises 17 such as the exploration of Africa and the settlement of Australia.

[03:27.16]In 1778, Banks was elected president of the Royal Society, a position he held for 42 years

[03:33.83]During these years Banks helped to develop the royal gardens at Kew into one of the greatest botanical gardens in the world.

[03:40.25]He accumulated 18 a great deal of knowledge about plants and agriculture.

[03:43.54]In growing strawberries Banks went back to the abandoned practice of spreading straw under the fruit to reduce the necessary amount of watering.

[03:50.73]He also built a greenhouse 19 to experiment with growing pineapples.

[03:55.01]It was Joseph Banks who made Kew a centre of scientific and economic research.

[03:59.32]INTEGRATING SKILLS

[04:03.06]Reading

[04:04.21]WILDLIEF AND GRARDEN ROSES

[04:06.87]In his youth Charles Darwin enjoyed all the freedom to experiment and do whatever he liked.

[04:12.70]The study of physics, chemistry, and later botany, was his hobby

[04:16.38]At the age of 22, Darwin was invited to join the scientific expedition on the Beagle.

[04:21.63]During its five-year voyage, the Beagle followed almost the same route as Cook’s Endeavour sixty years earlier.

[04:27.59]Darwin’s observations on the voyage let him to write his famous book On the Origin of Species.

[04:33.12]It was Darwin’s visit on the beagle to the Galapagos Isles 20 that gave him the key to his new theory.

[04:38.69]Darwin soon realized that the wildlife of the Galapagos Isles was very curious and deserved 21 special attention.

[04:44.28]Most of the life forms could be found nowhere else.

[04:47.80]There were even difference between the species of the different islands;

[04:50.89]yet all showed a clear relationship with those of America,

[04:53.63]though separated from that continent by about 600 miles.

[04:56.87]Darwin counted 225 flowering plants, of which he collected and brought home 193.

[05:03.22]Of these 100 were new species which are only found in the Galapagos islands.

[05:08.34]Altogether the group of island formed a little world within itself.

[05:12.12]Darwin first understood the development of different plant species from developments in bird species that he observed in Galapagos.

[05:18.60]He found 13 kinds of finches, related to each other in the structure of their beaks 22, tails,shape of body and colour of their feathers.

[05:25.68]The most curious fact was the differences in the size of the beaks.

[05:29.21]This could only be explained by the difference in habitat and source of food.

[05:32.92]The birds with broad beaks would eat hard seeds, while the birds with smaller beaks would eat soft seed or insects.

[05:39.42]Back home, in England, Darwin realised that differences in habitat could lead to explaining differences between species.

[05:46.47]During the 1840s and 1850s Gregor Mendel conducted his experiments with flowers and peas Mendel’s attraction to research was based on his love of nature.

[05:59.75]Although his experiments. Were designed to support the ideas concerning 23 the influence of environment upon plants,

[06:05.54]he found that many characteristics were passed on from one generation to the next,

[06:09.20]without influence by the environment.

[06:11.32]His research gave birth to the science of genetics.

[06:14.01]As a result of Darwin and Mendel’s research, scientists of the nineteenth century formed the belief that the influence of the environment was behind the development of new species.

[06:23.67]Still, both Darwin and Mendel observed that within species, different varieties could occur.

[06:28.95]Darwin studied many varieties of garden roses.

[06:31.98]It would take a next generation of scientists to bring the importance of the environment on species back in view.

[06:37.36]In 1922, Gote Turesson found evidence for existence of stable varieties within species in nature.

[06:44.55]He showed that differences between plants of one species occurred as result of environmental conditions in their habitat.

[06:51.05]He made his discoveries by studying a wild plant found on the Swedish west coast.

[06:55.62]When growing on rocks, the plant grows to a bush, having broad leaves and large flowers.

[07:00.56]However, when growing on sand, the plant grows close to the ground, having narrow leaves and small flowers

[07:06.31]If plants from one habitat were moved to the other of habitat,

[07:09.86]they changed their appearance and adapted to the new environment.

[07:12.99]The research of Darwin, Mendel and Turesson shows that both genetics and the environment are important to plants.

[07:18.79]For the improvement 24 of crops Mendel’s genetics were long considered the most important.

[07:23.13]However, Tursson’s findings 25 show that habitat,

[07:26.03]such as soil conditions, is of equal importance to the output of crops