Q.How many species of organisms in the world are endangered?
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The IUCN (International Union for Conservation of Nature and Natural Resources) maintains the Red Data Book, or Red List, recording the conservation status of species worldwide across nine categories, arranged in increasing order of extinction risk once a species is assessed: Not Evaluated (NE, not yet assessed), Data Deficient (DD, insufficient data to judge risk), Least Concern (LC, widespread and abundant), Near Threatened (NT, close to qualifying as threatened), Vulnerable (VU, population decline of roughly 30-50%+ over ten years or three generations), Endangered (EN, decline of roughly 50-70%+ over the same period), Critically Endangered (CR, extremely high risk, often fewer than 50 individuals remaining), Extinct in the Wild (EW, surv …
Conservation bodies periodically assess how many species worldwide are currently at risk of extinction, and the figure reflects the scale of the ongoing biodiversity crisis. …
According to IUCN Red List data, more than 15,500 species worldwide are currently facing extinction, reflecting the ongoing loss of biodiversity due to human activities.
The IUCN (International Union for Conservation of Nature) periodically publishes a Red List documenting species by threat category. Alongside historically documented extinctions (784 species over the last 500 years, including well-known cases like the Dodo, Quagga, and three subspecies of tiger), the Red List (2004) identified more than …
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- CBSE 2026Set 57/2/11 markMCQQ.Assertion (A) : IUCN Red List helps in identifying and protecting endangered species worldwide. Reason (R) : The list includes the species facing risk of extinction. (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation for Assertion (A). (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not correct explanation for Assertion (A). (C) Assertion (A) is true, Reason (R) is false. (D) Assertion (A) is false, Reason (R) is true.
›Reveal solutionSolution
Both the assertion and reason are true, and the reason correctly explains why the IUCN Red List is effective in identifying and protecting endangered species — it works precisely because it catalogues species at risk of extinction.
The IUCN Red List, formally known as the International Union for Conservation of Nature's Red List of Threatened Species, stands as one of the most comprehensive global inventories of the conservation status of biological species. Its primary function is to assess and document which species face the threat of extinction, providing a scientific foundation for conservation priorities worldwide.
The assertion states that the IUCN Red List helps in identifying and protecting endangered species globally. This is accurate. The Red List serves as a critical tool for conservationists, policymakers, and researchers by systematically evaluating thousands of species and categorizing them according to their extinction risk. These categories range from "Least Concern" through "Near Threatened," "Vulnerable," "Endangered," and "Critically Endangered" to "Extinct in the Wild" and "Extinct." By making this information publicly accessible, the Red List enables governments to frame protective legislation, helps direct conservation funding to the most threatened species, and raises public awareness about biodiversity loss.
The reason given is that the list includes species facing risk of extinction. This statement is also true and, crucially, it explains why the Red List is effective at its job. The entire purpose of the Red List is to identify which species are threatened — those facing a high, very high, or extremely high risk of extinction in the wild. Without this core function of documenting at-risk species, the Red List would have no basis for guiding conservation action. …
- CBSE 2026Set ZOOLOGY1 markMCQQ.Which organization publishes 'Red Data Book'?(a) UNEP(b) WWF(c) IUCN(d) GEF
›Reveal solutionSolution
The Red Data Book (Red List) documenting threatened and endangered species is published by IUCN.
The International Union for Conservation of Nature (IUCN), headquartered in Switzerland, maintains and publishes the Red Data Book, also called the Red List. It documents all plant and animal species that are rare, threatened, vulnerable, endangered, or extinct, categorising them by their degree of threat (e.g., Critically Endangered, Endangered, Vulnerable, Near …
- CBSE 2026Set ANNUAL1 markMCQQ.Red data book collects the record of which of the following?(a) Red flowered plants(b) Aquatic animals(c) Endangered plants and animals(d) Natural resources
›Reveal solutionSolution
The Red Data Book, maintained by the IUCN, documents species of plants and animals that are endangered or threatened with extinction.
The Red Data Book (published by the International Union for Conservation of Nature, IUCN) is the official global inventory of the conservation status of biological species. It lists species categorised by their level of threat — such as Extinct, Critically Endangered, Endangered, Vulnerable, and Near Threatened — covering both plants and animals.
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- CBSE 2026Set ANNUAL1 markQ.Define endangered species.
›Reveal solutionSolution
Endangered species face a high risk of extinction in the near future without conservation intervention.
As per conservation biology (and IUCN classification), an endangered species is one whose numbers have been reduced to a critical level, or whose habitats have been drastically reduced, such that the species is considered to be in immediate danger of extinction if the causal factors (habitat loss, over-exploitation, pollution, poaching, climate change, etc.) continue to operate. Examples in India include the Bengal tiger, the great Indian bustard, and several other species listed in the Red Data Book maintained by the IUCN, which categorizes species by their degree of threat (e.g., critically endangered, endangered …
- CBSE 2025Set ANNUAL1 markMCQQ.The Red Data Book deals with :(a) Endangered and extinct organisms(b) Endemic plants(c) Domestic animals(d) All of these
›Reveal solutionSolution
The Red Data Book, maintained by the IUCN, is the official catalogue of the world's threatened, endangered and recently extinct plant and animal species.
The Red Data Book (also called the IUCN Red List) contains documented information on all plants and animal species whose survival is threatened — ranging from vulnerable and endangered categories to species that have already gone extinct. It is used worldwide to identify and prioritise species and habitats that most need conservation ef …
- CBSE 2025Set ANNUAL1 markQ.Expand IUCN.
›Reveal solutionSolution
IUCN is the global body that assesses and documents the conservation status of species worldwide.
IUCN (International Union for Conservation of Nature, formerly also known as the International Union for Conservation of Nature and Natural Resources) is an international organisation that works on the conservation of nature and natural resources and is responsible for maintaining and periodically updatin …
- CBSE 2025Set ANNUAL1 markMCQQ.The term used to describe the species whose number of individuals is greatly reduced to a critical level.(a) Indeterminate(b) Rare(c) Vulnerable(d) Endangered
›Reveal solutionSolution
A species whose individual numbers have fallen to a critically low level, putting it at risk of extinction, is called Endangered.
The IUCN conservation categories describe a spectrum of risk. A species is termed Endangered when its population has declined to a critical level such that its survival in the wild is threatened if the causal factors continue to operate — it faces a very high risk of extinction in the near future. "Vulnerable" describes a species likely to move into the endangered category in the near future if the th …
- CBSE 2024Set ANNUAL1 markMCQQ.How many species of organisms in the world are endangered?(a) 15,500(b) 150(c) 5,500(d) 1,550
›Reveal solutionSolution
According to IUCN Red List data, more than 15,500 species worldwide are currently facing extinction, reflecting the ongoing loss of biodiversity due to human activities.
The IUCN (International Union for Conservation of Nature) periodically publishes a Red List documenting species by threat category. Alongside historically documented extinctions (784 species over the last 500 years, including well-known cases like the Dodo, Quagga, and three subspecies of tiger), the Red List (2004) identified more than …
- CBSE 2024Set ANNUAL1 markQ.What is Red Data Book?
›Reveal solutionSolution
The Red Data Book is IUCN's authoritative catalogue of threatened and endangered species worldwide, used to guide conservation priorities.
The Red Data Book (or Red List) is a comprehensive document, maintained and periodically updated by the International Union for Conservation of Nature (IUCN), which lists and provides detailed status information on species (plants, animals, fungi) that are threatened with extinction, categorising them by degree of risk (e.g., critically endangered, endangered, vulnerable). It serves as a crucial reference for priori …
- CBSE 2023Set ANNUAL1 markMCQQ.Red data book collects the record of which of the following?(a) Red flowered plants(b) Aquatic animals(c) Endangered plants and animals(d) Natural resources
›Reveal solutionSolution
The Red Data Book (maintained by the IUCN) documents species that are rare, threatened or endangered, serving as a key reference for conservation planning.
The International Union for Conservation of Nature (IUCN) publishes Red Data Books/Red Lists that catalogue species according to their risk of extinction (categories like Critically Endangered, Endangered, Vulnerable, etc.), based on population size, rate of decline, geographic range and other factors. This documentation …
- CBSE 2021Set D1 markMCQQ.Dodo is(a) Extinct species(b) Endangered species(c) Threatened species(d) None of these
›Reveal solutionSolution
The Dodo no longer exists anywhere on Earth, so it is an extinct species; the answer is (A).
The Dodo was a large flightless bird that lived on the island of Mauritius. Due to overhunting by humans and the introduction of predators, it was completely wiped out in the late 17th century.
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- CBSE 2021Set NC1 markQ.Expand IUCN.
›Reveal solutionSolution
IUCN is the International Union for Conservation of Nature, the organization responsible for assessing and publishing the global conservation status of species (the Red List).
IUCN — full form and role
IUCN stands for the International Union for Conservation of Nature and Natural Resources. It is a global environmental organization (headquartered in Gland, Switzerland) that works on nature conservation and the sustainable use of natural resources.
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