Answer explanation for Academic Reading Passage Sample 1 Population Viability Analysis.

Go to the Reading Passage - Population Viability Analysis.

 

Answer Explanation:

Question 28: Scientists are interested in the effect of forestry on native animals.
Answer: Yes.

Explanation: This is the most confusing question in this reading passage. The techniques and strategies that you have learned so far to find answers from a reading passage would easily assist you to decide that the right answer is 'Not Given'. Believe me, this was my first instinct as well. However, the right answer is 'Yes'. But why?

The first point to notice is that you have to find evidence for the answer from Part A, as mentioned in the reading passage. So even if any evidence is given otherwise in Part B or C, would not be applicable here. If you are still confused, read the question instruction again, which says 'Do the following statements agree with the views of the writer in Part A of Reading Passage 1?'.

Now we only have to search the proof within Part A of the paragraph and that has become a bit easier for us.

Look at the beginning of the Part A that says:

"To make political decisions about the extent and type of forestry in a region it is important to understand the consequences of those decisions. One tool for assessing the impact of forestry on the ecosystem is population viability analysis (PVA). This is a tool for predicting the probability that a species will become extinct in a particular region over a specific period."

It is certain that someone is interested in the effect of forestry on native animals but we are still not convinced if this "someone" is a scientist or not?

Don't be confused about the word 'political' as it does not mean only politicians are involved. In this reading passage 'to make political decisions' indicates the 'decision-making process' and the writer implies that the decision-making process leads directly to consequences.
 
The Part A of the reading passage includes:

"One tool for assessing the impact of forestry on the ecosystem is population viability analysis (PVA)." It should be obvious that the tool (PVA) is being used by scientists and ecosystems include the native animals."

Still not convinced? Let me try for one more time-

What group of people are interested to know about the impact of forestry on the ecosystem and who would use tools to measure/assess that? Scientists.

Still convinced that the answer is 'Not Given'? Let us know your logic in the comment section.

 

Question 29.  PVA has been used in Australia for many years.
Answer: No.

Explanation: The Part A of the reading passage indicates that-

"It (PVA) has been successfully used in the United States... ...and there is now an enormous potential for using population viability to assist wildlife management in Australia’s forests.  "

It should be clear that PVA is yet to be used in Australia but it has a potential to become handy to assist wildlife managements in Australia's forests. Potential means 'possible, likely, prospective, future, and probable' which clearly explains that it might be used in the future and has not been used and tested.  

 

Question 30: A species is said to be extinct when only one individual exists.
Answer: No.

Explanation: The sentence in Part A of the reading passage clearly mention that "A species becomes extinct when the last individual dies." So finding the answer to this question should be very easy for you and this is quite straight forward. 

 

Question 31: Extinction is a naturally occurring phenomenon.
Answer: Not Given.

Explanation: According to the question instruction, we have to find evidence from the Part A of this reading passage for question 31 as well.

Look at the last sentence of the Part A which states -

"To make a prediction about extinction we need to understand the processes that can contribute to it and these fall into four broad categories which are discussed below."

It makes it clear that the reasons why extinction occurs fall into four broad categories which we still don't know and would not want to know as they are not included in Part A of the reading passage. They might be a natural phenomenon or could be man-made.

Be aware: Do not apply your general knowledge or subject matter expertise while answering the IELTS reading passages. In reality, extinctions of different species might be a natural phenomenon. To answer this question you have to rely on the information given in this reading passage, not your previous knowledge or expertise.  

Tips: A group of questions (28 -31 in this case) in IELTS reading usually appears chronologically; i.e. follow the order in the text of the passage. Since you found the answer to the question 30 in the line "A species becomes extinct when the last individual dies, for the answer to the question 31 look the next line of this paragraph, NOT from the beginning of the paragraph.


Question 32- 35: Part B of the reading passage has four paragraphs namely a), b), c) and d). We need to find suitable processes that are listed in the table, i.e. i-vi. Do not write process name in your answer sheet. Rather write the roman numbers i - vi. Notice that there are six processes while you need to pick four out of these to match with the 4 paragraphs given. 

 

Question 32: Paragraph A

Answer: vi  (The haphazard nature of reproduction) [ In your answer sheet write only vi, we have included the answer in the () for the purpose of explaining it. ]

Explanation: According to the paragraph A) of Part B) -

"Small populations will fluctuate enormously because of the random nature of birth and death and these chance fluctuations can cause species extinctions even if, on average, the population size should increase. Taking only this uncertainty of ability to reproduce into account, extinction is unlikely if the number of individuals in a population is above about 50 and the population is growing. "

Main points/ keywords/ keyphrases to notice here - random nature of birth and death, uncertainty of ability to reproduce into account. 

Thus "The haphazard nature of reproduction" is the most suitable process that the writer has described here. 

 

Question 33: Paragraph B

Answer: iii (An imbalance of the sexes) [ In your answer sheet write only iii, we have included the answer in the () for the purpose of explaining it. ]

Explanation: According to the paragraph B) of Part B) -

"This is particularly true if there is a very small number of one sex. For example, if there are only 20 individuals of a species and only one is a male, all future individuals in the species must be descended from that one male. For most animal species such individuals are less likely to survive and reproduce. Inbreeding increases the chance of extinction."

Thus "An imbalance of the sexes" is the process the writer has described in this paragraph.

 

Question 34: Paragraph C

Answer: i (Loss of ability to adapt) [ In your answer sheet write only i, we have included the answer in the () for the purpose of explaining it. ]

Explanation: According to the paragraph C) of Part B -

"Without genetic variability, a species lacks the capacity to evolve and cannot adapt to changes in its environment or to new predators and new diseases. The loss of genetic diversity associated with reductions in population size will contribute to the likelihood of extinction. "

Thus the "Loss of ability to adapt" is the process the writer has described in this paragraph.

Be aware that it is tempting to pick "Evolution" as the answer to this question if you do not understand the paragraph. It is talking about a process which lets a species extinct and the lack/loss of adaptability is the right answer here, NOT the evaluation.

 

Question 35: Paragraph D

Answer: ii (Natural disasters) [ In your answer sheet write only ii, we have included the answer in the () for the purpose of explaining it. ]

Explanation: According to the paragraph D) of Part B -

"Recent research has shown that other factors need to be considered. Australia’s environment fluctuates enormously from year to year. These fluctuations add yet another degree of uncertainty to the survival of many species. Catastrophes such as fire, flood, drought or epidemic may reduce population sizes to a small fraction of their average level..."

Note that - Environmental fluctuations, catastrophes like flood, drought or epidemic are all natural disasters.

Thus "Natural Disaster" is the process the writer has described in this paragraph.


Questions 36-38: Note that you have to answer the questions 36 to 38 based on Part C of the paragraph. You need to fill the gaps with word(s) that are TAKEN FROM THE PASSAGE and DO NOT use more than three words to fill a single gap. Also, the sentence must make sense and become grammatically accurate when you use your words to fill the gaps.

Question 36: While the population of a species may be on the increase, there is always a chance that small isolated groups .......... (36) ..........

Answer: (either one of the following) 

  • become extinct
  • will become extinct
  • may become extinct
  • could become extinct
  • will not survive
  • may not survive

Explanation: You have to pick three or fewer than three words to fill this gap. Make sure you use word(s) that has appeared in the reading passage. In this case extinct and survive are both accurate as they both come from the reading passage. However, you have to use become, may become... will not survive or any of the right answer to make the sentence grammatically correct. 

You could be sure of this answer from the excerpt -

"A species that occurs in five isolated places each containing 20 individuals will not have the same probability of extinction as a species with a single population of 100 individuals in a single locality."

 

Question 37: Survival of a species depends on a balance between the size of a population and its .......... (37) .........

Answer: (either one of the following) 

  • distribution
  • locality

Explanation: You must not use more than three words to fill this gap. Make sure you use word(s) that has appeared in the reading passage. In this case extinct and survive are both accurate as they both come from the reading passage.

You could be sure of this answer from the line(s) -

"Besides these processes, we need to bear in mind the distribution of a population... ...Where logging occurs (that is, the cutting down of forests for timber) forest-dependent creatures in that area will be forced to leave. Ground-dwelling herbivores may return within a decade. However, arboreal marsupials (that is animals which live in trees) may not recover to pre-logging densities for over a century. As more forests are logged, animal population sizes will be reduced further. "

 

Question 38: The likelihood that animals which live in forests will become extinct is increased when ..........  (38) ...........

Answer: (either one of the following) 

  • logging occurs
  • logging takes place

Explanation: You must not use more than three words to fill this gap. Make sure you use word(s) that has appeared in the reading passage. In this case extinct and survive are both accurate as they both come from the reading passage.

You could be sure of this answer from the excerpt -

"Where logging occurs (that is, the cutting down of forests for timber) forest-dependent creatures in that area will be forced to leave. Ground-dwelling herbivores may return within a decade. However, arboreal marsupials (that is animals which live in trees) may not recover to pre-logging densities for over a century. As more forests are logged, animal population sizes will be reduced further. "

Caution: "logging occur/ logging take place" are grammatically inaccurate and hence if you write either of that, your answer would be treated as a wrong answer. The same rule applies for the spelling mistakes. Even if your answer is correct, you won't get any mark for a spelling mistake. Thus 'logging occurs' would not be treated as a correct answer as 'loggin' is not the correct spelling.

 

Question 39: An alternative heading for the passage could be:

Answer: B.

Explanation: The right answer here would be "Influential factors in assessing survival probability" (i.e. B). The reading passage already has a heading, which is 'Population Viability Analysis'. This question now asks you to find an alternative and suitable heading for this same reading passage and the four options are given. By the time you have reached the question 39, you already have a fair idea of what the reading passage is about. 

Option A) The protection of native flora and fauna - as an alternative heading is not at all suitable as the reading passage has not talked about how to protect the trees and animals. In the same way, option C) 'An economic rationale for the logging of forests' is totally off-topic. Option D) includes 'Preventive measures for the extinction of a species' which is also off topic as the reading passage is about the four main factors that could be used to assess the survival probability of a species.

Thus the most obvious choice is B) "Influential factors in assessing survival probability". 

This is the end of the answers explanation for the reading passage "Population Viability Analysis".

Have any question? Why don't you leave a comment and let us know!

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0 # Asma Khan 2017-09-17 19:05
I'm very grateful to you that you incorporate the explanation of the answers. It's assisting me to rectify the confusing answers of the questions.
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0 # Ayan 2017-08-30 17:39
Sir, as per my knowledge in any format of T/F/NG or Y/N/NG, we are not allowed to assume our answers. We just have to stick to the content provided there. So in which way we have to take that the statement was given by scientist.? Please clear me.! Thank you.
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0 # Maria 2017-08-26 10:29
Dear Sir,
One more thing to discuss herewith, please; My answer to question 36 and 37 are: will survive and genetic diversity, respectively. I do not fully agree with the answers given on this website and not completely sure about my own answers. Please guide.
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0 # Maria 2017-08-26 09:16
Hello Sir, we have been told that in T/F/NG and Y/N/NG types of questions, we cannot guess the answers, they have to be confirmed, while in paragraph A, there is an implication that PVA is used by the scientists, but not made clear. Could you please share the trick of solving such question types in which implication is the answer?
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0 # Debra 2017-08-23 17:26
Thank you.
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0 # Carolyn Kaira 2017-07-24 11:49
Thank you for this website. I am learning new things.
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0 # Sathia N Mannath 2017-06-25 08:02
For Q. 36= While the population of a species may be on the increase, there is always a chance that small isolated groups .......... (36) .......... may survive or may not extinct is the answer (in paragraph 'C', it is mentioned that small isolated groups will not have the same probability of extinction as compared to single locality large population).

A species that occurs in five isolated places each containing 20 individuals will not have the same probability of extinction as a species with a single population of 100 individuals in a single locality."

Please guide me if I am wrong.
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0 # Sumam 2017-06-08 06:31
Very well explained. Awesome act.
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0 # IELTS Mentor 2017-06-10 18:17
Thanks a lot, Suman.
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0 # Nayerm Hossain 2017-05-21 08:31
Yes, it's a good website to improve your reading module from here & get a good mark and also a well exploration of each passage.
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+4 # Giulia 2017-03-23 10:03
About the question 37, could be "genetic diversity" correct? "...a reduction in population size decreases the genetic diversity of a population and increases the probability of extinction ..." So there should be a balance. Thank you.
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+7 # Deep 2017-01-23 14:52
For question 28, What if the Forest Officials or Environmentalists or Nature Conservationists are interested in studying the effects? How can this still referred to "scientists"?
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