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BIODIVERSITY-WHAT IS IT EXACTLY
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A
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It seems
biodiversity has become a buzzword beloved of politicians,
conservationists, protesters and scientists alike. But what exactly is it?
The Convention on Biological Diversity, an international agreement to
conserve and share the planet’s biological riches, provides a good working definition:
biodiversity comprises every form of life, from the smallest microbe to the
largest animal or plant, the genes that give them their specific
characteristics and the ecosystems of which they are apart.
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B
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In October, the World
Conservation Union (also known as the IUCN) published its updated Red List
of Threatened Species, a roll call of 11,167 creatures facing extinction –
121 more than when the list was last published in 2000. But the new figures
almost certainly underestimate the crisis. Some 1.2 million species of
animals and 270,000 species of plants have been classified, but the
well-being of only a fraction has been assessed. The resources are simply
not available. The RJCN reports that 5714 plants are threatened, for
example, but admits that only 4 per cent of known plants have been
assessed. And, of course, there are thousands of species that we have yet
to discover. Many of these could also be facing extinction.
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C
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It is
important to develop a picture of the diversity of life on Earth now so
that comparisons can be made in the future and trends identified. But it
isn’t necessary to observe every single type of organism in an area to get
a snapshot of the health of the ecosystem. In many habitats, there are
species that are particularly susceptible to shifting conditions, and these
can be used as indicator species.
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D
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In the media, it is usually
large, charismatic animals such as pandas, elephants, tigers and whales
that get all the attention when the loss of biodiversity is discussed.
However, animals or plants far lower down the food chain are often the ones
vital for preserving habitats – in the process saving the skins of those
more glamorous species. These are known as keystone species.
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E
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By studying
the complex feeding relationships within habitats, species can be
identified that have a particularly important impact on the environment.
For example, the members of the fig family are the staple food for hundreds
of different species in many different countries, so important that
scientists sometimes call figs “jungle burgers”. A whole range of animals,
from tiny insects to birds and large mammals, feed on everything from the
tree’s bark and leaves to its flowers and fruits. Many fig species have
very specific pollinators. There are several dozen species of fig trees in
Costa Rica, and a different type of wasp has evolved to pollinate each one.
Chris Lyle of the Natural History Museum in London – who is also involved
in the Global Taxonomy Initiative of the Convention on Biological Diversity
– points out that if fig trees are affected by global warming, pollution,
disease or any other catastrophe, the loss of biodiversity will be
enormous.
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F
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Similarly, sea otters play a
major role in the survival of giant kelp forests along the coasts of
California and Alaska. These “marine rainforests” provide a home for a wide
range of other species. The kelp itself is the main food of purple and red
sea urchins and in turn, the urchins are eaten by predators, particularly
sea otters. They detach an urchin from the seabed then float to the surface
and lie on their backs with the urchin shell on their tummy, smashing it
open with a stone before eating the contents. Urchins that are not eaten
tend to spend their time in rock crevices to avoid the predators. This
allows the kelp to grow – and it can grow many centimeters in a day. As the
forests form, bits of kelp break off and fall to the bottom to provide food
for the urchins in their crevices. The sea otters thrive hunting for sea
urchins in the kelp, and many other fish and invertebrates live among the
fronds. The problems start when the sea otter population declines. As large
predators they are vulnerable – their numbers are relatively small so
disease or human hunters can wipe them out. The result is that the sea
urchin population grows unchecked and they roam the seafloor eating young
kelp fronds. This tends to keep the kelp very short and stops forests
developing, which has a huge impact on biodiversity.
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G
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Conversely,
keystone species can also make dangerous alien species: they can wreak
havoc if they end up in the wrong ecosystem. The cactus moth, whose
caterpillar is a voracious eater of prickly pear was introduced to
Australia to control the rampant cacti. It was so successful that someone
thought it would be a good idea to introduce it to the Caribbean islands
that had the same problem. It solved the cactus menace, but unfortunately,
some of the moths have now reached the US mainland – borne on winds and in
tourists’ luggage – where they are devastating the native cactus
populations of Florida.
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H
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Organizations like the
Convention on Biological Diversity work with groups such as the UN and with
governments and scientists to raise awareness and fund research. A number
of major international meetings – including the World Summit on Sustainable
Development in Johannesburg this year – have set targets for governments
around the world to slow the loss of biodiversity. And the CITES meeting in
Santiago last month added several more names to its list of endangered
species for which trade is controlled. Of course, these agreements will
prove of limited value if some countries refuse to implement them.
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I
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There is
cause for optimism, however. There seems to be a growing understanding of
the need for sustainable agriculture and sustainable tourism to conserve
biodiversity. Problems such as illegal logging are being tackled through
sustainable forestry programs, with the emphasis on minimizing the use of
rainforest hardwoods in the developed world and on rigorous replanting of
whatever trees are harvested. CITES is playing its part by controlling
trade in wood from endangered tree species. In the same way, sustainable
farming techniques that minimize environmental damage and avoid
monoculture.
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J
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Action at a national level
often means investing in public education and awareness. Getting people
like you and me involved can be very effective. Australia and many European
countries are becoming increasingly efficient at recycling much of their
domestic waste, for example, preserving natural resources and reducing the
use of fossil fuels. This, in turn, has a direct effect on biodiversity by
minimizing pollution, and an indirect effect by reducing the number of
greenhouse gases emitted from incinerators and landfill sites. Preserving
ecosystems intact for future generations to enjoy is obviously important,
but biodiversity is not some kind of optional extra. Variety may be “the
spice of life”, but biological variety is also our life-support system.
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Questions 27-33
Do the following statements agree with
the information given in Reading Passage 2
In boxes 27-33 on your answer sheet,
write
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TRUE
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if the
statement is true
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FALSE
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if the
statement is false
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NOT GIVEN
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if the information is not
given in the passage
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27
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The term “biodiversity” consists of living creatures and the
environment that they live in.
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28
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There are species that have not been researched because it’s
unnecessary to study all creatures.
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29
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It is not
necessary to investigate all creatures in a certain place.
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30
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The press more often than not focuses on animals well-known.
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31
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There is a
successful case that cactus moth plays a positive role in the US.
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32
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Usage of hardwoods is forbidden in some European countries.
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33
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Agriculture
experts advise farmers to plant single crops in the field in terms of
sustainable farming
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Questions 34-39
Summary
Complete
the following summary of the paragraphs of Reading Passage, using no more
than two words from the Reading Passage for each answer.
Write
your answers in boxes 34-39 on your answer sheet.
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Because of the ignorance brought by media, people tend to neglect
significant creatures called 34………………..Every creature has diet connections
with others, such as 35………………. which provide a majority of foods for other
species. In some states of America, the decline in the number of sea otters
leads to the boom of 36 ………………. An impressing case is that imported 37 ………………..successfully
tackles the plant cacti in 38 ………………. However, the operation is needed for
the government to increase its financial support in 39………………..
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