Population Viability Analysis Reading Answers
The Population Viability Analysis Reading Answers consist of a total of 40 questions, that need to be answered within 60 minutes. IELTS Population Viability Analysis Reading Answers are taken from IELTS Academic Reading Cambridge 1, Reading Passage 3. IELTS Reading topic Population Viability Analysis Reading Answers discusses the factors on which the extinction and survival of different animal species depend, why variation in a population is necessary for evolution and survival. IELTS Reading Practice Papers help candidates with different types of reading passages.
The IELTS reading sample questions and answers on Population Viability Analysis contains four types of questions:
- True/False/Not given
- Matching list contents
- Complete the sentence with NOT MORE THAN THREE WORDS
- Give a heading for the passage
Check: Get 10 Free IELTS Sample Papers
Check: Register for IELTS Coaching - Join for Free Trial Class Now
Section 1
Read the Passage to Answer the Following Questions
Population Viability Analysis Reading Answers
- 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 has been successfully used in the United States to provide input into resource exploitation decisions and assist wildlife managers and there is now enormous potential for using population viability to assist wildlife management in Australia’s forests. A species becomes extinct when the last individual dies. This observation is a useful starting point for any discussion of extinction as it highlights the role of luck and chance in the extinction process. 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.
- A) Early attempts to predict population viability were based on demographic uncertainty whether an individual survives from one year to the next will largely be a matter of chance. Some pairs may produce several young in a single year while others may produce none in that same year. 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.
B) Small populations cannot avoid a certain amount of inbreeding. 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.
C) Variation within a species is the raw material upon which natural selection acts. 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.
D) 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. When allowance is made for these two additional elements of uncertainty the population size necessary to be confident of persistence for a few hundred years may increase to several thousand. - Besides these processes, we need to bear in mind the distribution of a 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. 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 that 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. Regardless of the theory or model that we choose, a reduction in population size decreases the genetic diversity of a population and increases the probability of extinction because of any or all of the processes listed above. It is, therefore, a scientific fact that increasing the area that is loaded in any region will increase the probability that forest-dependent animals will become extinct.
Questions 1-4: Do the following statements agree with the views of the writer in Part A of Reading Passage 1?
YES, if the statement agrees with the writer
NO, if the statement contradicts the writer
NOT GIVEN, if it is impossible to say what the writer thinks about this
- Scientists are interested in the effect of forestry on native animals.
- PVA has been used in Australia for many years.
- A species is said to be extinct when only one individual exists.
- Extinction is a naturally occurring phenomenon.
(Guide: To answer the true or false IELTS reading type questions, you need to read the passage and identify specific information. You need to understand the opinion of the author and understand the given information.
Tip: Use paraphrasing of the given information and the answer options. If you find a supporting sentence, the answer is YES; if you find an opposing sentence, the answer is NO; and if there is no relevant information, the answer is NOT GIVEN. The answers usually come in order. )
Answer 1: YES
Keyword Location: Paragraph A
Supporting Sentence: "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."
Explanation: A link exists between the consequences of decisions and the decision-making process itself.
Read More IELTS Reading Related Articles
Answer 2: NO
Keyword Location: Paragraph A
Supporting Sentence: "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."
Explanation: The statement directly contradicts the writer. It is stated in the paragraph that PVA has been successfully used in the USA.
Answer 3: NO
Keyword Location: Paragraph A
Supporting Sentence: "A species becomes extinct when the last individual dies."
Explanation: The statement contradicts the writer. The question says that a species is said to be extinct when only one individual, male or female, is alive. But the line from the passage directly contradicts this. In the passage, the author says a species is said to be extinct when all of its individuals have died.
Answer 4: NOT GIVEN
Questions 5-8: These questions are based on Part B of Reading Passage 1.
In paragraphs A to D the author describes four processes that may contribute to the extinction of a species.
Match the list of processes (i-vi) to the paragraphs.
Write the appropriate number (i-vi) in boxes 5-8 on your answer sheet.
| Paragraphs | Processes |
|---|---|
|
5. Paragraph A 6. Paragraph B 7. Paragraph C 8. Paragraph D |
i. Loss of ability to adapt ii. Natural disasters iii. An imbalance of the sexes iv. Human disasters v. Evolution vi. The haphazard nature of reproduction |
(Guide: In this type of IELTS Reading question you need to match the answer options with the given information in the paragraphs. The paragraphs are usually numbered as A, B, C, D, and the list of answers as i, ii, iii, etc. You will need to understand the information given in the passage and relate the ideas in the paragraph and the question.
Tip: Paraphrasing would be of great help to get the correct answer. Identify the necessary keywords to locate the answers. You may find the answers in order. )
Answer 5: vi. The haphazard nature of reproduction
Keyword Location: Paragraph B; Section A
Supporting Sentence: "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.
Explanation: A few pairs may produce many young in a year but others may not. Thus, the “haphazard nature of reproduction” is the fittest option for this paragraph.
Answer 6: iii. An imbalance of the sexes
Keyword Location: Paragraph B; Section B
Supporting Sentence: "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."
Explanation: Small populations fail to avoid inbreeding. This paragraph talks about the disparity in the number of males and females in a species, how that leads to inbreeding. The individuals born from inbreeding are unfit for survival and thus the species may get extinct.
Answer 7: i. Loss of ability to adapt
Keyword Location: Paragraph B; Section C
Supporting Sentence: "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. "
Explanation: Variation of a species decides natural selection - a species may lack the capacity to evolve and fail to adapt to the changes in its environment or to new predators and new diseases.
Answer 8: ii. Natural disasters
Keyword Location: Paragraph B; Section D
Supporting Sentence: "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..."
Explanation: Disasters like fire, flood, drought, or epidemic often reduce the population sizes. Thus it is clear that this paragraph talks about natural disasters and their effect on population sizes.
Questions 9-11: Based on your reading of Part C, complete the sentences below.
Use NO MORE THAN THREE WORDS for each answer.
Write your answers in boxes 9-11 on your answer sheet.
While the population of a species may be on the increase, there is always a chance that small isolated groups .......... (9) .......... Survival of a species depends on a balance between the size of a population and its .......... (10) ......... The likelihood that animals that live in forests will become extinct is increased when .......... (11) ...........
(Guide: To answer this type of IELTS reading question, you need to go through the passage and find the necessary keywords. You can use a maximum of three words to fill up the gaps.
Tip: Focus on proper nouns, numbers, capital letters, or special characters inside the passage. Scanning the passage for keywords is the best technique to find correct answers. )
Answer 9: will(/may) not survive, or, [will (/ may/ could) become extinct]
Keyword Location: Paragraph C
Supporting Sentence: "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."
Explanation: A species, found in five isolated places and each of these contains 20 individuals will not have this probability of extinction as a species with a single population of 100 individuals in a single locality.
Answer 10: locality/ distribution
Keyword Location: Paragraph C
Supporting Sentence: "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. "
Explanation: Besides these processes, we need to bear in mind the distribution of a population, where they are living, and how many individuals are living together. Paragraph C informs that animals living in forests are forced to leave due to human activities and this affects their population growth.
Answer 11: logging takes place/ logging occurs
Keyword Location: Paragraph C
Supporting Sentence: "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 that 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. "
Explanation: Where logging occurs (that is, the cutting down of forests for timber) forest-dependent creatures in that area will be forced to leave.
Question 12: Choose the appropriate letter A-D and write it in box 12 on your answer sheet.
- An alternative heading for the passage could be:
- The protection of native flora and fauna.
- Influential factors in assessing survival probability
- An economic rationale for the logging of forests
- Preventive measures for the extinction of a species
(Guide: Identify the main idea of the reading passage and distinguish between the main and supporting details. It carries only one point, so invest as little time as possible.
Tip: Read and understand the meaning of the given title options. Read the starting and the ending of the paragraphs carefully. )
Answer 12: B. Influential factors in assessing survival probability
Keyword Location: Entire passage
Supporting Sentence: The entire passage.
Explanation: Different factors depicting the survival probability are mentioned in the IELTS Reading passage, how human activities disrupt their natural habitat and force them to leave, endangering their survival.
Comments