Reading Passage: Biodiversity

A
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 a part.

B
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 IUCN reports that 5,714 plants are threatened, for example, but admits that only 4% 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.

C
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.

D
In the media, it is usually large, charismatic animals such as pandas, elephants, tigers, and whales that get all the attention when a 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. There are known as keystone species.

E
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 the fig tree 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.

F
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 from developing, which has a huge impact on biodiversity.

G
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 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.

H
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.

I
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.

J
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.

Questions 1–7

Do the following statements agree with the information given in the Reading Passage?
In boxes 1–7 on your answer sheet, write:

• TRUE if the statement is true
• FALSE if the statement is false
• NOT GIVEN if the information is not given

1. The term “biodiversity” consists of living creatures and the environment that they live in.
2. There are species that have not been researched because it’s unnecessary to study all creatures.
3. It is not necessary to investigate all creatures in a certain place.
4. The press more often than not focuses on animals well-known.
5. There is a successful case where the cactus moth plays a positive role in the US.
6. Usage of hardwoods is forbidden in some European countries.
7. Agriculture experts advise farmers to plant single crops in the field in terms of sustainable farming.

Questions 8–13

Complete the following summary using NO MORE THAN TWO WORDS from the Reading Passage for each answer.

Because of the ignorance brought by media, people tend to neglect significant creatures called 8 ________. Every creature has diet connections with others, such as 9 ________, 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 10 ________. An impressive case is that imported 11 ________ successfully tackles the plant cacti in 12 ________. However, the operation is needed for the government to increase its financial support in 13 ________.

1. Biodiversity

• Definition: The variety of life in the world, including different species of plants, animals, and ecosystems.
• Vietnamese: Đa dạng sinh học
• IELTS TUTOR xét ví dụ từ bài đọc: Biodiversity comprises every form of life, from the smallest microbe to the largest animal or plant.
• Vietnamese Example: Đa dạng sinh học bao gồm mọi dạng sống, từ vi sinh vật nhỏ nhất đến động vật hoặc thực vật lớn nhất.

2. Ecosystem

• Definition: A biological community of interacting organisms and their physical environment.
• Vietnamese: Hệ sinh thái
• IELTS TUTOR xét ví dụ từ bài đọc: The genes that give them their specific characteristics and the ecosystems of which they are a part.
• Vietnamese Example: Các gen quyết định đặc điểm riêng biệt của chúng và hệ sinh thái mà chúng là một phần.

3. Extinction

• Definition: The state or process of a species, family, or larger group ceasing to exist.
• Vietnamese: Sự tuyệt chủng
• IELTS TUTOR xét ví dụ từ bài đọc: A roll call of 11,167 creatures facing extinction.
• Vietnamese Example: Danh sách gồm 11.167 sinh vật đối mặt với sự tuyệt chủng.

4. Indicator species

• Definition: Species that are particularly sensitive to environmental changes and can indicate the health of an ecosystem.
• Vietnamese: Loài chỉ thị
• IELTS TUTOR xét ví dụ từ bài đọc: In many habitats, there are species that are particularly susceptible to shifting conditions, and these can be used as indicator species.
• Vietnamese Example: Trong nhiều môi trường sống, có những loài đặc biệt nhạy cảm với điều kiện thay đổi và chúng có thể được sử dụng làm loài chỉ thị.

5. Keystone species

• Definition: Species that have a disproportionately large impact on their ecosystem compared to their abundance.
• Vietnamese: Loài chủ chốt
• IELTS TUTOR xét ví dụ từ bài đọc: 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.
• Vietnamese Example: Những loài động thực vật ở vị trí thấp hơn trong chuỗi thức ăn thường là những loài quan trọng để bảo tồn môi trường sống – và chúng được gọi là loài chủ chốt.

6. Pollinators

• Definition: Animals or insects that transfer pollen from one flower to another, facilitating plant reproduction.
• Vietnamese: Các loài thụ phấn
• IELTS TUTOR xét ví dụ từ bài đọc: Many fig species have very specific pollinators.
• Vietnamese Example: Nhiều loài sung có các loài thụ phấn rất đặc biệt.

7. Kelp

• Definition: Large brown seaweed that grows in underwater forests in shallow oceans.
• Vietnamese: Tảo bẹ
• IELTS TUTOR xét ví dụ từ bài đọc: Sea otters play a major role in the survival of giant kelp forests along the coasts of California and Alaska.
• Vietnamese Example: Rái cá biển đóng vai trò quan trọng trong việc tồn tại của các rừng tảo bẹ khổng lồ dọc theo bờ biển California và Alaska.

8. Crevices

• Definition: Narrow cracks or openings, especially in rock or the ground.
• Vietnamese: Kẽ hở, khe nứt
• IELTS TUTOR xét ví dụ từ bài đọc: Urchins that are not eaten tend to spend their time in rock crevices to avoid the predators.
• Vietnamese Example: Những con nhím biển không bị ăn thường dành thời gian trong các khe đá để tránh kẻ săn mồi.

9. Voracious

• Definition: Very eager for something, especially for food.
• Vietnamese: Phàm ăn, tham lam
• IELTS TUTOR xét ví dụ từ bài đọc: The cactus moth, whose caterpillar is a voracious eater of prickly pear.
• Vietnamese Example: Sâu của loài bướm xương rồng là những kẻ tham ăn quả lê gai.

10. Prickly pear

• Definition: A type of cactus with spiny pads and edible fruit.
• Vietnamese: Lê gai
• IELTS TUTOR xét ví dụ từ bài đọc: The cactus moth, whose caterpillar is a voracious eater of prickly pear.
• Vietnamese Example: Bướm xương rồng có sâu là loài tham ăn quả lê gai.

11. Sustainable

• Definition: Able to be maintained at a certain level without depleting resources.
• Vietnamese: Bền vững
• IELTS TUTOR xét ví dụ từ bài đọc: There seems to be a growing understanding of the need for sustainable agriculture and sustainable tourism to conserve biodiversity.
• Vietnamese Example: Có vẻ như sự hiểu biết ngày càng tăng về nhu cầu nông nghiệp và du lịch bền vững để bảo tồn đa dạng sinh học.

12. Recycling

• Definition: The process of converting waste into reusable material.
• Vietnamese: Tái chế
• IELTS TUTOR xét ví dụ từ bài đọc: Australia and many European countries are becoming increasingly efficient at recycling much of their domestic waste.
• Vietnamese Example: Úc và nhiều quốc gia châu Âu ngày càng trở nên hiệu quả trong việc tái chế phần lớn rác thải sinh hoạt của họ.

13. Greenhouse gases

• Definition: Gases that trap heat in the atmosphere and contribute to global warming.
• Vietnamese: Khí nhà kính
• IELTS TUTOR xét ví dụ từ bài đọc: Reducing the number of greenhouse gases emitted from incinerators and landfill sites.
• Vietnamese Example: Giảm số lượng khí nhà kính phát thải từ các lò đốt rác và bãi chôn lấp.

1. TRUE
2. FALSE
3. TRUE
4. TRUE
5. FALSE
6. NOT GIVEN
7. NOT GIVEN
8. keystone
9. fig family
10. sea urchins
11. cactus moth
12. Australia
13. Public education