IELTS Reading Practice: Biodiversity (Full Answer Key & Detailed Analysis)

A lost sea otter can cause an entire “underwater rainforest” to collapse. A harmless caterpillar in Australia can become a devastating invasive species in the United States. The IELTS “Biodiversity” reading passage tells fascinating stories about the fragile balance of our ecosystems. This ECE article serves as a detailed guide to help you track these complex connections, understand the reasoning behind each answer, and build a solid foundation of knowledge on this topic.

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. These 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?

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

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 ________.

Summary of the Biodiversity Reading Passage

This passage defines and discusses the importance of “Biodiversity.”

• Definition & Crisis (A, B): “Biodiversity” encompasses every form of life, genes, and ecosystems. The article points out that the Red List of threatened species actually underestimates the crisis, as there are insufficient resources to assess all known species, and countless others remain undiscovered.
• Indicator & Keystone Species (C, D): It is not necessary to study every organism; instead, we can use “indicator species.” The media often focuses on “charismatic” animals, but “keystone species” lower down the food chain are the ones truly vital for habitat preservation.
• Examples of Keystone Species (E, F): The article provides two examples: (1) The fig family, the “jungle burgers” and staple food for hundreds of species. (2) Sea otters, which control the population of sea urchins, thereby protecting kelp forests.
• The Downside of Keystone Species (G): When placed in the wrong ecosystem, a keystone species can become invasive. For example, the cactus moth was introduced to Australia to control cacti but later spread to the US, devastating native cactus populations.
• Action & Optimism (H, I, J): International organizations are working toward conservation. There is reason for optimism, such as growing awareness of sustainable agriculture and tourism, reforestation programs, and individual actions like recycling. Biodiversity is not an “optional extra” but our life-support system.

Key Vocabulary from the Passage

1. buzzword (n) (Paragraph A): a trendy or popular word or phrase.
2. underestimate (v) (Paragraph B): to estimate something as being smaller or less important than it actually is.
3. a fraction of (phrase) (Paragraph B): a small part of something.
4. susceptible to (adj) (Paragraph C): likely to be influenced or harmed by something.
   • Example: “…particularly susceptible to shifting conditions…”
5. charismatic (adj) (Paragraph D): having a compelling charm or appeal.
   • Example: “…large, charismatic animals such as pandas…”
6. keystone species (n.p) (Paragraph D): a species that has a disproportionately large effect on its environment.
7. pollinators (n) (Paragraph E): animals that transfer pollen between plants.
8. crevices (n) (Paragraph F): narrow openings or cracks, typically in rock.
9. wreak havoc (phrase) (Paragraph G): to cause great destruction or chaos.
   • Example: “…they can wreak havoc if they end up in the wrong ecosystem.”
10. voracious (adj) (Paragraph G): having a huge appetite; devouring large quantities.
    • Example: “…a voracious eater of prickly pear.”
11. rampant (adj) (Paragraph G): flourishing or spreading unchecked.
12. sustainable agriculture (n.p) (Paragraph I): farming in a way that meets current needs without compromising the future.
13. monoculture (n) (Paragraph I): the cultivation of a single crop in a given area.
14. life-support system (n.p) (Paragraph J): a system that provides the essential conditions for life.

Answer Key and Detailed Explanations

1. TRUE

• Question: The term “biodiversity” consists of living creatures and the environment that they live in.
• Evidence (Paragraph A): “…biodiversity comprises every form of life… and the ecosystems of which they are a part.”
• Explanation: “Living creatures” corresponds to “every form of life,” and “the environment that they live in” corresponds to “ecosystems.”

2. FALSE

• Question: There are species that have not been researched because it’s unnecessary to study all creatures.
• Evidence (Paragraph B): “…the well-being of only a fraction has been assessed. The resources are simply not available.”
• Explanation: The passage states that species remain unresearched because “resources are simply not available,” not because it is “unnecessary.” This contradicts the premise of the question.

3. TRUE

• Question: It is not necessary to investigate all creatures in a certain place.
• Evidence (Paragraph C): “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.”
• Explanation: “Investigate all creatures” is synonymous with “observe every single type of organism.” This matches the passage perfectly.

4. TRUE

• Question: The press more often than not focuses on animals well-known.
• Evidence (Paragraph D): “In the media, it is usually large, charismatic animals such as pandas, elephants, tigers, and whales that get all the attention…”
• Explanation: “The press” is synonymous with “the media.” “Animals well-known” corresponds to “large, charismatic animals.” “Focuses on” is synonymous with “get all the attention.”

5. FALSE

• Question: There is a successful case where the cactus moth plays a positive role in the US.
• Evidence (Paragraph G): “…some of the moths have now reached the US mainland… where they are devastating the native cactus populations of Florida.”
• Explanation: The cactus moth was successful in Australia and the Caribbean, but in the US, it is “devastating” native populations. This contradicts the idea of it playing a “positive role.”

6. NOT GIVEN

• Question: Usage of hardwoods is forbidden in some European countries.
• Evidence (Paragraph I): “…with the emphasis on minimizing the use of rainforest hardwoods in the developed world…”
• Explanation: “Developed world” may include European countries, but the passage only mentions “minimizing” the use, not that it is “forbidden.”

7. FALSE

• Question: Agriculture experts advise farmers to plant single crops in the field in terms of sustainable farming.
• Evidence (Paragraph I): “…sustainable farming techniques that minimize environmental damage and avoid monoculture.”
• Explanation: Sustainable farming requires “avoiding monoculture.” This contradicts the advice to “plant single crops.”

8. keystone species

• Evidence (Paragraph D): “…animals or plants far lower down the food chain are often the ones vital… These are known as keystone species.”
• Explanation: The summary states that the media causes us to neglect significant creatures called “keystone species.”

9. fig family

• Evidence (Paragraph E): “For example, the members of the fig family are the staple food for hundreds of different species…”
• Explanation: The summary asks for an example of a species that provides food for many others. The “fig family” is the first example provided.

10. sea urchins

• Evidence (Paragraph F): “The problems start when the sea otter population declines… The result is that the sea urchin population grows unchecked…”
• Explanation: The decline of sea otters leads to the “boom” (grows unchecked) of “sea urchins.”

11. cactus moth

• Evidence (Paragraph G): “The cactus moth… was introduced to Australia to control the rampant cacti.”
• Explanation: The species imported to “tackle” the cactus problem is the “cactus moth.”

12. Australia

• Evidence (Paragraph G): “The cactus moth… was introduced to Australia to control the rampant cacti.”
• Explanation: The place where the moth successfully solved the cactus problem is “Australia.”

13. public education

• Evidence (Paragraph J): “Action at a national level often means investing in public education and awareness.”
• Explanation: The summary asks what the government needs to invest in. Paragraph J explicitly mentions “public education.”

Conclusion

The “Biodiversity” reading passage concludes with a powerful message: biodiversity is not an “optional extra,” but our very “life-support system.” Hopefully, by analyzing the answers and vocabulary in this passage, you have not only learned how to approach an IELTS Reading task but also gained a deeper understanding of the importance of every creature, no matter how small, in maintaining the fragile balance of our planet.