研究生英語下冊課文篇章分析PPT

1、part discourse analyze and summaryThe Man Who Discovered Mother NaturePart1(1-2) The introduction to James Lovelock and his work environment.Part2(3-8) The background of how Lovelock proposed his theory-the Gaia Hypothesis.Part3(9-13)The definition and content of Gaia Hypothesis.Part4(14-17)Peoples

2、responses to Gaia Hypothesis.Part5(18-19) A futuristic scheme proposed by Lovelock and his cooperator by use Gaia Hypothesis.Part1(1-2) The introduction to James Lovelock and his work environment. Why the author regards James Lovelock as a modern Ben Franklin?Benjamin Franklin Drawing Electricity fr

3、om the Sky c. 1816 at the Philadelphia Museum of ArtAs a scientist, he was a major figure in the American Enlightenment and the history of physics for his discoveries and theories regarding electricity. As an inventor, he is known for the lightning rod, bifocals, and the Franklin stove, among other

4、inventions.Benjamin Franklin was one of the Founding Fathers of the United States. A renowned polymath, Franklin was a leading author, printer, political theorist, politician, postmaster, scientist, inventor, civic activist, statesman, and diplomat.Part2(3-8) The background of how Lovelock proposed

5、his theory-the Gaia Hypothesis.Para.3 NASA asked Lovelock for help because he is an expert in analyzing chemical traces in the environment .Para.4 Lovelock predicted there is no life on Mars,and his prediction was proved later.Para.5 Lovelock began to study what conditions might help to initiate lif

6、e.Para.6 The old theory which explain earths “good luck” has a fatal flaw .Para.7 Lovelock came up with a new hypotheses to explain his idea.Para.8 Lovelocks neighbor named the new hypotheses Gaia.A physical basis for life detection experimentsNature Vol. 207, No. 4997, pp. 568-570, August 7, 1965 R

7、ecognition of Life:Life is one member of the class of phenomena which are open or continuous reaction systems able to decrease their entropy at the expense of substances or energy taken in from the environment and subsequently rejected in a degraded form.Detection of Life on MarsSearch for orderSear

8、ch for non-equilibrium.Thermodynamics and the recognition of alien biospheres Proceedings of the Royal Society B. 189, 167-181 (1975).The abundance of gases in the planetary atmospheres. Vertical scale logarithm to the base 10 of the abundances. Part2(3-8) The background of how Lovelock proposed his

9、 theory-the Gaia HypothesisPart3prooforganism living a like actsearth definitionGaia nameGaia HypothesisPart3(9-13) The definition and content of Gaia Hypothesis.Para.9 The Gaia Hypothesis has momentous current significance and far-reaching historical significance.98 percent carbon dioxideproduced a

10、 super greenhouse effect“The first bacteria consumed carbon dioxide, limiting the effect of this greenhouse gas.around 3.7 billion years ago,there is no food and oxygenon earth blue green algae began to use sunlight to make foodand produce oxygenIf weather warmed plankton emits more dimethylsulfidet

11、he resulting sulfur particles in the air might produce more abundant droplets and reflective clouds, to cool the environment.The rise of oxygen in Earths earlyocean and atmosphereNATURE VOL 506 p307-315 20 FEB.2014 Evidence for oxygen-producing photosynthesis before the GOEPhotosynthetic life requir

12、es both light and a source of reducing poweran electron donor. Because the ubiquitous H2O molecule is the electron donor for oxygenic photosynthesis, it is reasonable to expect that the initiation of oxygenic photosynthesis would supercharge carbon fluxes through the biosphere. Three alternative ele

13、ctron donors could powerdelivery of significant quantities of organic carbon tomarine sediments during the Archaean without releasing O2: hydrogen sulphide (H2S), ferrous iron (Fe2+) and molecular hydrogen (H2).Photosynthesis based on H2S is difficult to maintain at steady state without an external

14、carbon , and many organic-rich Archaean shales were deposited from Fe21-containing waters, arguing against an H2S-based pathway. Photosynthesis based on Fe2+ is another possibility, but this metabolismgenerates two physically associated particulate species (organic carbon and solid Fe-oxide minerals

15、) at a relatively constant ratio, and these will mutually annihilate throughmicrobial iron reduction at roughly the same ratio.The rise of oxygen in Earths earlyocean and atmosphereNATURE VOL 506 p307-315 20 FEB.2014The significance of organic carbon content in sedimentary rocks of Archaean age (2.5

16、Gyr old). H2-based photosynthesis is more difficult to assess. We can, however, obtain some estimates of the TOC values as a function of H2 fluxes to the photic zone. Even given the very conservative assumptions used here, it is difficult to explain typical Archaean TOC values by H2-based photosynth

17、esis, let alone themost elevated values fromthe record.We are thus left with oxygenic photosynthesis as themost likely explanation for organic-rich shales in the pre-GOE ocean.Part3(9-13)Anatomy of blue-green algae Oxygen-Dependent Proton Efflux in CyanobacteriaJOURNAL OF BACTERIOLOGY Vol 158 p. 609

18、-614 May 1984Hypotheses on the interaction and localization of photosynthetic and respiratory electron transport in blue-green algaePart4(14-17)Peoples responses to Gaia Hypothesis.Para.14 Some people like Gaia because of their own interests and or their own notions of Gaia. Para.15 Some scientists

19、and Lovelock hold different ideas on Gaia.Para.16 Gaia brings together scientists of different fields to ask profound questions about how living things and the planet interact.Para.17 Lovelock has done some work to answer to the critic. Its just too late for it, he says. Perhaps if wed gone along ro

20、utes like that in 1967, it might have helped. But we dont have time. All these standard green things, like sustainable development, I think these are just words that mean nothing. I get an awful lot of people coming to me saying you cant say that, because it gives us nothing to do. I say on the cont