Today, we have a Population Viability Analysis reading answers topic for your IELTS reading preparation. So, what is PVA?

Population viability analysis or PVA refers to the acquisition of concepts, theoretical frameworks, conceptual and quantitative tools that ecologists employ to assess extinction risk and estimate future scenarios of population increase and decrease.

To read more about it, check out the sections below. Learn how to answer the questions which will come in your reading exam.

Population Viability Analysis Reading Answers

This article contains a reading passage topic with two sets of questionnaires for your upcoming IELTS examination. We have solved them for you to help you understand how to come up with the answer.

Population Viability Analysis IELTS Reading Answers Section A

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.

यह भी पढ़ें: पुरातत्व की प्रकृति और उद्देश्य: आईईएलटीएस रीडिंग टेस्ट के लिए रीडिंग उत्तर खोजें

Population Viability Analysis IELTS Reading Answers Section B

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.


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.


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.


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.

Population Viability Analysis IELTS Reading Answers Section C

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.

यह भी पढ़ें: आईईएलटीएस रीडिंग परीक्षा में एमसीक्यू प्रकार के प्रश्न: इसे कैसे करें, यहां बताया गया है

Population Viability Analysis Reading Questions & Answer for IELTS Exam

आईईएलटीएस परीक्षा प्रश्न: शब्दावली

Q. Synonym of sensitive

Ans. Delicate

Q. Synonym of limit

Ans. Cap

Q. Antonym of beneficial

Ans. Detrimental

Q. Antonym of distinct

Ans. Indistinct

आईईएलटीएस Exam Questions: Fill in the Gaps

Q. While some _____ have already been completed, the results have only been used for conservation choices in a small number of cases.

Ans. extensive PVAs.

Q. The ecology in _____ varies greatly from year to year.

Ans. Australia.

Q. _____ will continue to shrink as more forests are logged.

Ans. Animal population numbers.

यह भी पढ़ें: दुर्लभ संसाधनों की समस्या: उत्तर पढ़ने के साथ एक आईईएलटीएस विषय

सुझावों for IELTS Reading Passages

Prior Knowledge Should be Integrated

Consider what you have already known about the topic you’ll be reading before reading the text. Consider how the reading links to other course themes, and inquire as to why your lecturer chose the material. Identify any relevant personal experiences or second-hand expertise. Focus on the things you’d like to know about the book or questions you’d want to attempt to address while you read.

परीक्षण करना The Text

Don’t dive in headfirst. Take a quick look through the material, noticing headers, graphs, tables, illustrations, bolded terms, summaries, and crucial questions. Try reading the introduction and conclusion to get a sense of the important points. Predict what the segment or page will be about and what the major topics will be after previewing it.

Monitor Your Own Progress

You are the only one who can ensure that you are engaged while reading! You are not paying much attention if you can think about what you could eat for supper or what will happen next on your favourite Netflix show!


After reading a few paragraphs, a page, or a piece of material divided by a header or subheading, describe the major themes and two or three significant facts in your own words. These highlights can be used as the foundation for your reading notes.


The reading passages can be tricky and complex at the same time. Many candidates find this section head-scratching. But it is all about practice and knowledge. You can easily pass this segment if you go with the right approach. Follow the tips given in this article to see if it helps in solving these passages.

For more reading passages, go to the blog section of आईईएलटीएस निंजा.

यह भी पढ़ें: आईईएलटीएस रीडिंग में प्रश्नों के मिलान शीर्षक प्रकार: इसे कैसे करें यहां बताया गया है

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