Chapter 13: Biodiversity and Conservation Assertion-Reason Questions | biology Class 12 CBSE

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 1

Logic Check

Assertion (A): India is one of the 12 mega diversity countries of the world. Reason (R): India has about 8.1% of the world's species diversity despite having only 2.4% of the world's land area.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): Species diversity generally decreases as we move from the equator towards the poles. Reason (R): Tropical environments are less seasonal and more constant, promoting niche specialisation and greater species diversity.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 3

Logic Check

Assertion (A): The current rate of species extinction is estimated to be 100 to 1,000 times faster than pre-human rates. Reason (R): Species extinctions are primarily caused by natural events like volcanic eruptions and glaciations in modern times.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 4

Logic Check

Assertion (A): Zoological parks and botanical gardens are examples of in situ conservation. Reason (R): In situ conservation involves protecting species within their natural habitat.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 5

Logic Check

Assertion (A): Sacred groves in Meghalaya are important for biodiversity conservation. Reason (R): Sacred groves serve as the last refuges for many rare and threatened plant species.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 6

Logic Check

Assertion (A): The number of fungi species in the world exceeds the combined total species of fishes, amphibians, reptiles, and mammals. Reason (R): Fungi are heterotrophic organisms that play a key role in decomposition.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 7

Logic Check

Assertion (A): Habitat loss and fragmentation is the most important cause of biodiversity loss. Reason (R): Tropical rainforests that once covered more than 14% of Earth's land surface now cover no more than 6%.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 8

Logic Check

Assertion (A): The species-area relationship on a logarithmic scale gives a straight line. Reason (R): On a natural (non-log) scale, the species-area relationship is a rectangular hyperbola.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 9

Logic Check

Assertion (A): Introduction of alien species can lead to extinction of native species. Reason (R): Alien species often have no natural predators in the new environment, allowing them to outcompete indigenous species.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 10

Logic Check

Assertion (A): Communities with high species diversity tend to be more stable and productive. Reason (R): David Tilman's experiments showed that species-rich plots had less year-to-year variation in total biomass and higher productivity.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 11

Logic Check

Assertion (A): Cryopreservation is a method of ex situ conservation. Reason (R): In cryopreservation, gametes of threatened species are preserved in viable condition at very low temperatures for long periods.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): Amphibians appear to be more vulnerable to extinction than other animal groups. Reason (R): Amphibians are found only in aquatic habitats and are threatened exclusively by water pollution.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): The Convention on Biological Diversity was held in Rio de Janeiro in 1992. Reason (R): The World Summit on Sustainable Development was also held in Rio de Janeiro in 2002.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): Biodiversity hotspots are regions with very high species richness and high degree of endemism. Reason (R): Biodiversity hotspots are regions where no species face extinction threats.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 15

Logic Check

Assertion (A): The Amazon rainforest is called the 'lungs of the planet.' Reason (R): The Amazon rainforest produces about 20% of the total oxygen in the Earth's atmosphere through photosynthesis.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): Co-extinction occurs when one partner in a coevolved plant-pollinator mutualism becomes extinct. Reason (R): Co-extinction happens because of overexploitation of species by humans.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 17

Logic Check

Assertion (A): Genetic diversity within a single species is an important component of biodiversity. Reason (R): India has more than 50,000 genetically different strains of rice, illustrating high intraspecific genetic diversity.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 18

Logic Check

Assertion (A): Over-exploitation is one of the four major causes of biodiversity loss. Reason (R): Steller's Sea Cow and Passenger Pigeon became extinct largely due to overexploitation by humans.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 19

Logic Check

Assertion (A): Species richness is higher in tropical regions than in temperate regions. Reason (R): Tropical regions have been subjected to frequent glaciations which promoted rapid speciation.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 20

Logic Check

Assertion (A): More than 70% of all the animal species recorded on Earth are animals. Reason (R): Among animals, insects are the most species-rich group, making up more than 70% of all animal species.

Reasoning Options

ByteNotes

Chapter sections

Chapter 13: Biodiversity and Conservation | Assertion-Reason

Assertion (A): India is one of the 12 mega diversity countries of the world. Reason (R): India has about 8.1% of the world's species diversity despite having only 2.4% of the world's land area.

Assertion (A): Species diversity generally decreases as we move from the equator towards the poles. Reason (R): Tropical environments are less seasonal and more constant, promoting niche specialisation and greater species diversity.

Assertion (A): The current rate of species extinction is estimated to be 100 to 1,000 times faster than pre-human rates. Reason (R): Species extinctions are primarily caused by natural events like volcanic eruptions and glaciations in modern times.

Assertion (A): Zoological parks and botanical gardens are examples of in situ conservation. Reason (R): In situ conservation involves protecting species within their natural habitat.

Assertion (A): Sacred groves in Meghalaya are important for biodiversity conservation. Reason (R): Sacred groves serve as the last refuges for many rare and threatened plant species.

Assertion (A): The number of fungi species in the world exceeds the combined total species of fishes, amphibians, reptiles, and mammals. Reason (R): Fungi are heterotrophic organisms that play a key role in decomposition.

Assertion (A): Habitat loss and fragmentation is the most important cause of biodiversity loss. Reason (R): Tropical rainforests that once covered more than 14% of Earth's land surface now cover no more than 6%.

Assertion (A): The species-area relationship on a logarithmic scale gives a straight line. Reason (R): On a natural (non-log) scale, the species-area relationship is a rectangular hyperbola.

Assertion (A): Introduction of alien species can lead to extinction of native species. Reason (R): Alien species often have no natural predators in the new environment, allowing them to outcompete indigenous species.

Assertion (A): Communities with high species diversity tend to be more stable and productive. Reason (R): David Tilman's experiments showed that species-rich plots had less year-to-year variation in total biomass and higher productivity.

Assertion (A): Cryopreservation is a method of ex situ conservation. Reason (R): In cryopreservation, gametes of threatened species are preserved in viable condition at very low temperatures for long periods.

Assertion (A): Amphibians appear to be more vulnerable to extinction than other animal groups. Reason (R): Amphibians are found only in aquatic habitats and are threatened exclusively by water pollution.

Assertion (A): The Convention on Biological Diversity was held in Rio de Janeiro in 1992. Reason (R): The World Summit on Sustainable Development was also held in Rio de Janeiro in 2002.

Assertion (A): Biodiversity hotspots are regions with very high species richness and high degree of endemism. Reason (R): Biodiversity hotspots are regions where no species face extinction threats.

Assertion (A): The Amazon rainforest is called the 'lungs of the planet.' Reason (R): The Amazon rainforest produces about 20% of the total oxygen in the Earth's atmosphere through photosynthesis.

Assertion (A): Co-extinction occurs when one partner in a coevolved plant-pollinator mutualism becomes extinct. Reason (R): Co-extinction happens because of overexploitation of species by humans.

Assertion (A): Genetic diversity within a single species is an important component of biodiversity. Reason (R): India has more than 50,000 genetically different strains of rice, illustrating high intraspecific genetic diversity.

Assertion (A): Over-exploitation is one of the four major causes of biodiversity loss. Reason (R): Steller's Sea Cow and Passenger Pigeon became extinct largely due to overexploitation by humans.

Assertion (A): Species richness is higher in tropical regions than in temperate regions. Reason (R): Tropical regions have been subjected to frequent glaciations which promoted rapid speciation.

Assertion (A): More than 70% of all the animal species recorded on Earth are animals. Reason (R): Among animals, insects are the most species-rich group, making up more than 70% of all animal species.

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