was possible in the past = (Russian – возможно было); might is more unsure than may.
Study the sentences.
1.The development of DNA might have completely replaced any earlier form of life.
2.This might have been a remarkable coincidence.
Give Russian correspondence:
Yet (but), it is likely, it is unlikely, hardly, since (as, for, because), a number of (a set of, a range of), on (further), few (a small amount), thus (so, therefore), original (initial), as (shows an action in a process), to lead to (to result in, to give rise to), both … and, eventually (finally), dramatic (sudden and radical), ultimate (complete), the more ……, the less; the very, so (therefore)
HOW DID LIFE ORIGINATE ON EARTH?
Study the passage. Mind the underlined grammar points.
What follows is my personal attempt to answer this question. I don’t claim any great originality or depth, but it is the best I can do at the moment. My answer to this question is based on Darwin’s idea of natural selection. I think that some very primitive form of life arose spontaneously on earth from chance combinations of atoms. This early form of life was probably a large molecule. But it was probably not DNA, since the chances of forming a whole DNA molecule by random combinations are small. The early form of life would have reproduced itself.
The quantum uncertainty principle and the random thermal motions of the atoms would mean that there were a certain number of errors in the reproduction. Most of these errors would have been fatal to the survival of the organism or its ability to reproduce. Such errors would not be passed on to future generations but would die out. Very few errors would be beneficial, by pure chance. The organisms with the beneficial errors would be more likely to survive and reproduce. Thus, they would tend to replace the original organisms.
The development of the double helix structure of the DNA may have been a quantum jump in the early stages. This was probably such an advance that it completely replaced any earlier form of life, whatever that may have been. As evolution progressed, DNA would have led to the development of the central nervous system. Creatures that correctly
− 41 −
recognized the implications of the data gathered by their sense organs would be more likely to survive and reproduce.
The human race has carried this to another stage. We are very similar to higher apes, both in our body and in our DNA; but a slight variation in our DNA has enabled us to develop language. This has meant that we can hand down information and accumulated experience from generation to generation, in spoken and eventually in written form. The effect has been a dramatic speed-up of evolution. Previously, the results of experience could be handed down only by the slow process of encoding them into DNA through random errors in reproduction. It took more than three billion years to evolve up to the human race. But in the course of the last ten thousand years, we have developed written language This has enabled us to progress from cave dwellers to the point where we can ask about the ultimate theory of the universe.
Stephen Hawking
FYI
1.the quantum uncertainty principle − Heisenberg uncertainty principle states that one can’t measure simultaneously both the position and the velocity of a particle. The more accurately we measure the one, the less accurately we measure the other. This uncertainty is not very important at the present time, where things are far apart, so that a small uncertainty in position does not make much difference. But in the very early universe, everything was very close together, so there was quite a lot of uncertainty.
2.a quantum jump – a great change or advance
3.an evolution is a process of gradual change that takes place over many generations, during which animals, plants, insects, etc, slowly change some of their physical characteristics.
Vocabulary Notes
1.random – arbitrary – unplanned – chaotic
2.an error – a mistake
3.beneficial – useful – with a plus sign
4.tend to V – if something tends to happen, it happens.
5.an advance – progress
6.whatever – no matter what – any
7.an implication – a consequence – an effect
−42 −
8.to be similar to – to be like
9.to enable – to allow
10.previously – before
11.a cave-dweller – someone who lives in a cave
12.simultaneously – at the same time
13.to be apart – when things are apart, there is a distance between
them
POST-READING TASK
(To be done at home in writing)
I. Summarize the passage by answering the questions.
1.How did a very primitive form of life arise according to Darwin?
2.What was a very primitive form of life like?
3.Why wasn’t it DNA?
4.What caused errors in the reproduction?
5.What creatures would be more likely to survive and reproduce?
6.Are the DNA of a higher ape and that of a human being similar?
7.What did developing a language mean for humans?
II. Write out the statements which you find doubtful, if any. III. Put in the prepositions.
1.It is the best I can do … the moment.
2.My answer … this question is based … Darwin’s idea … natural selection.
3.The chances … forming a DNA molecule … random combinations
…atoms are very small.
4.There were a certain number … errors … the reproduction.
5.Very few errors would be beneficial, …pure chance.
6.The development …the double helix structure … the DNA may have been a quantum jump … the early stages.
7.DNA would have led … the development … the central nervous system.
8.Humans are very similar … higher apes: both … their body and … their DNA.
9.Humans can hand down information and accumulated experience
…generation … generation.
−43 −
IV. Give words close in meaning. |
|
1. because |
7. random |
2. original |
8. a mistake |
3. therefore |
9. a progress |
4. a set of |
10. to be like |
5. to lead to |
11. at the same time |
6. finally |
|
V. Formulate your arguments in favor or against Darwin’s idea. Use: I think (consider, believe, suppose, feel) that …; I don’t agree
that …..; I doubt that …; It’s incredible that …; It is disputable that … ; It’s unbelievable that ...; by pure chance
CLASS EXERCISES
Exercise 1 (in pairs)
Prefix a noun with the proper Adj. Put Adj. between an article and a noun. Follow the passage. Model: a fatal mistake
1. natural |
a the organism |
2. primitive |
b a form of life |
3. large |
c the uncertainty principle |
4. random |
d selection |
5. quantum |
e an error |
6. certain |
f chance |
7. future |
g combinations |
8. pure |
h a number of errors |
9. original |
i the structure |
10. double helix |
j a molecule |
11. fatal |
k a generation |
Exercise 2 (do it yourself) What do you think?
Study grammar point V and change the statements using may or might + have V3.
Remember: might is less sure than may.
1. Some very primitive form of life arose spontaneously on earth from chance combinations of atoms.
− 44 −
2.This early form of life was probably a large molecule.
3.There were a certain number of errors in the reproduction.
4.Such errors died out.
5.The development of the double structure of the DNA was probably such an advance that it completely replaced any earlier form of life.
Exercise 3 (do it yourself) What do you think?
Study grammar point IV and change the sentences using
S + is likely + have V3 S + is unlikely + have V3
Model: It was probably not DNA.
It is unlikely to have been DNA.
1.There were a certain number of errors in the reproduction.
2.Most of these errors were fatal to the survival of the organism.
3.Such errors were not passed on to future generations.
4.Such errors died out.
5.A very few errors were beneficial.
6.The organisms with these beneficial errors replaced the original, unimproved ones.
7.The development of DNA was one such improvement in the early stages.
8.That was probably such an advance that it completely replaced any earlier form of life.
9.Evolution led to the development of the nervous system.
− 45 −