PART 4 You will hear an interview with a scientist called Peter Crane, who is
talking about an ancient tree called the gingko. For questions 24 to 30,
choose the best answer (A, B or C).
Interviewer: Thank you for coming into our studio today, Peter, to tell us about your
research into an ancient species of tree called the gingko. First of all, how did
you develop an interest in it?
Peter: | think that anyone who's seriously interested in plants inevitably comes
across the gingko tree pretty early in their training, because very unusually,
it's a single plant species with no known living relatives; what particularly
fascinated me was the fact that it's been essentially unchanged for more than
two hundred million years. Other people are attracted by its distinctive leaf -
once you see it, you don't forget it.
Interviewer: When was the gingko first cultivated?
Peter: Our best estimate is about one thousand years ago in China, which is
somewhat late. There's a lot of Chinese literature from before that time, and
it doesn't mention the gingko, while it does mention a lot of other plants. The
evidence points to the fact that the gingko was probably always a rather rare
tree, until it first attracted the attention of people about a thousand years ago,
when they realised it could be cultivated as a source of nuts.
Interviewer: And does the gingko tree have medical uses?
Peter: The plant itself has long been valued for its healing properties. The medicinal
uses in the East and the West have gone in different directions, using two
different parts of the plant: mainly the seeds in the East, and mainly the leaves
in the West. In the West, work has been done on the leaves to see whether
they contain substances that might help improve people's memories. The
results, however, have shown no strong evidence for such powers.
Interviewer: What else do humans use the gingko tree for?
Peter: Well, it's a very popular tree in city streets all over the world. It's incredibly
tough, so can tolerate conditions that might kill other types of tree. It's hard to
know exactly why, but the leaves are particularly unattractive to insects that
harm other trees. And it seems to survive in a street setting: its roots aren't
getting much oxygen, they're getting a lot of salt and goodness knows what
else is getting poured on them, but it seems relatively resistant to that.
Interviewer: You're interested in the benefits of street trees in general, aren't you, Peter?
Peter: That's right, | am. They're important for a number of reasons. One advantage
is that trees along a street make it feel narrower and cause drivers to go more
slowly. And obviously they provide shade, making people feel a lot more
comfortable; they don't mind being outside if they can be in the shade. And
so trees help bring all the benefits that come from that: kids playing outside,
neighbours keeping an eye on each other's houses, people encouraged to
linger in a shopping area that they would otherwise walk right through.
Interviewer: Do you think there are lessons we can learn from the gingko about preserving
other plant species?
Peter: Well, because humans have distributed gingko around the planet, they have
helped ensure the species' long-term survival. There are probably a couple
of wild original populations of gingko tree still left in China, but even those
may have been aided by people. Obviously, we should try to preserve animals
and plants in their native habitats, but in the same way that we've used
other methods for conserving large mammals, | think conservation through
widespread cultivation is essential for preserving plant diversity for the future.
Interviewer: And finally, does working on such an ancient tree species affect your view of
the world?
Peter: Yes, as humans, one of our biggest shortcomings is that we can't see the
long term. So reflecting on a plant like gingko that was around in very different
ecosystems hundreds of millions of years ago, really makes our own species
seem very young.
Now you will hear Part Four again.
That is the end of Part Four.
There will now be a pause of five minutes for you to copy your answers
onto the separate answer sheet. Be sure to follow the numbering of all the
questions. I shall remind you when there is one minute left, so that you
are sure to finish in time.
That is the end of the test. Please stop now. Your supervisor will now collect
all the question papers and answer sheets.