When you consider it from a human perspective, and clearly it would be
difficult for us to do otherwise, life is an odd thing. It couldn't
wait to get going, but then, having got going, it seemed in very
little hurry to move on.
Consider the lichen. Lichens are just about the hardiest visible
organisms on Earth, but among the least ambitious. They will grow
happily enough in a sunny churchyard, but they particularly thrive in
environments where no other organism would go - on blowy mountaintops
and Arctic wastes, wherever there is little but rock and rain and
cold, and almost no competition. In areas of Antarctica where
virtually nothing else will grow, you can find vast expanses of lichen
- 400 types of them - adhering devotedly to every wind-whipped rock.
For a long time, people couldn't understand how they did it. Because
lichens grew on bare rock without evident nourishment or the
production of seeds, many people - educated people - believed they
were stones caught in the process of becoming plants. 'Spontaneously,
inorganic stone becomes living plant!' rejoiced one observer, a Dr
Hornschuch, in 1819.
Closer inspection showed that lichens were more interesting than
magical. They are in fact a partnership between fungi and algae. The
fungi excrete acids which dissolve the surface of the rock, freeing
minerals that the algae convert into food sufficient to sustain both.
It is not a very exciting arrangement, but it is a conspicuously
successful one. The world has more than twenty thousand species of
lichens.
Like most things that thrive in harsh environments, lichens are
slow-growing. It may take a lichen more than half a century to attain
the dimensions of a shirt button. Those the size of dinner plates,
writes David Attenborough, are therefore 'likely to be hundreds if not
thousands of years old'. It would be hard to imagine a less fulfilling
existence. 'They simply exist,' Attenborough adds, 'testifying to the
moving fact that life even at its simplest level occurs, apparently,
just for its own sake.'
It is easy to overlook this thought that life just is. As humans we
are inclined to feel that life must have a point. We have plans and
aspirations and desires. We want to take constant advantage of all the
intoxicating existence we've been endowed with. But what's life to a
lichen? Yet its impulse to exist, to be, is every bit as strong as
ours - arguably even stronger. If I were told that I had to spend
decades being a furry growth on a rock in the woods, I believe I would
lose the will to go on. Lichens don't. Life, in short, just wants to
be. But - and here's an interesting point - for the most part it
doesn't want to be much.
This is perhaps a little odd, because life has had plenty of time to
develop ambitions. If you imagine the 4,500 million years of Earth's
history compressed into a normal earthly day, then life begins very
early, about 4:00 a.m., with the rise of the first simple,
single-celled organisms, but then advances no further for the next
sixteen hours. Not until almost eight-thirty in the evening, with the
day five-sixths over, has the Earth anything to show the universe but
a restless skin of microbes. Then, finally, the first sea plants
appear, followed twenty minutes later by the first jellyfish and the
enigmatic Ediacaran fauna first seen by Reginald Sprigg in Australia.
At 9:04 p.m. trilobites swim onto the scene, followed more or less
immediately by the shapely creatures of the Burgess Shale. Just before
10:00 p.m. plants begin to pop up to the land. Soon after, with less
than two hours left in the day, the first land creatures follow.
Thanks to ten minutes or so of balmy weather, by 10.24 the Earth is
covered in the great carboniferous forests whose residues give us all
our coal, and the first winged insects are evident. Dinosaurs plod
onto the scene just before 11:00 p.m. and hold sway for about
three-quarters of an hour. At twenty-one minutes to midnight they
vanish and the age of mammals begins. Humans emerge one minute and
seventeen seconds before midnight. The whole of our recorded history,
on this scale, would be no more than a few seconds, a single human
lifetime barely an instant. Throughout this greatly speeded-up day,
continents slide about and bang together at a clip that seems
positively reckless. Mountains rise and melt away, ocean basins come
and go, ice sheets advance and withdraw. And throughout the whole,
about three minute, somewhere on the planet there is a flashbulb pop
of light marking the impact of a Manson-sized meteor or larger. It's a
wonder that anything at all can survive in such a pummeled and
unsettled environment. In fact, not many things do for long.
Perhaps an even more effective way of grasping our extreme recentness
as a part of this 4.5-billion-year-old picture is to stretch your arms
to their fullest extent and imagine that width as the entire history
of the Earth. On this scale, according to John McPhee in Basin and
Range, the distance from the fingertips of one hand to the wrist of
the other is Precambrian. All of complex life is in one hand, 'and in
a single stroke with a medium-grained nail file you could eradicate
human history'.
Fortunately, that moment hasn't happened, but the chances are good
that it will. I don't wish to interject a note of gloom just at this
point, but the fact is that there is one other extremely pertinent
quality about life on Earth: it goes extinct. Quite regularly. For all
the trouble they take to assemble and preserve themselves, species
crumple and die remarkably routinely. And the more complex they get,
the more quickly they appear to go extinct. Which is perhaps one
reason why so much of life isn't terribly ambitious.
1.The author compresses four and half billion years to a day
a)
to help us comprehend the changes and their relative duration in
earth's history.
b)
to show that man has existed for only a minute or so on a day scale.
c)
to enable us to visualise the geological changes in their true perspective.
d)
to make us realize how worthless an individual life is.
2
Lichens are 'more interesting than magical' because of
a)
the symbiotic relationship by which they exist.
b)
their being thought to be transformed forms of stones.
c)
the prosaic down-to-earth explanation of their existence.
d)
a mind-boggling 20,000 species of lichens have survived the test of time.
3
The image of a nailfile eradicating human history is used to
a)
explain why life isn't ambitious.
b)
argue in favour of simple life forms.
c)
indicate the extreme fragility of our existence.
d)
make man realise that he is far too insignificant in the larger scheme
of God and destiny.
4
The tone of the author in the last para of the passage is
a)
pessimistic
b)
speculative
c)
evocative
d)
despondent
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