ROUTERA


Chapter 15 Biodiversity and its conservation

Class 12th Biology Chapter Assertion and Reason


1.

Assertion (A): Biodiversity is the variety of life forms on Earth, including different species, ecosystems, and genetic diversity.
Reason (R): Biodiversity is important for ecosystem stability and the survival of species.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biodiversity encompasses species, ecosystems, and genetic diversity, all of which contribute to ecosystem stability and resilience.


2.

Assertion (A): Hotspots of biodiversity are regions with a large number of species, especially endemics.
Reason (R): Biodiversity hotspots are areas that are rich in species but are also threatened by human activities.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Hotspots contain a high number of endemic species but are under threat from habitat destruction and other human activities, requiring urgent conservation efforts.


3.

Assertion (A): India is considered one of the 17 megadiverse countries in the world.
Reason (R): India is home to a large variety of ecosystems and a wide range of species.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: India hosts numerous species and ecosystems, including tropical forests, deserts, and wetlands, making it a megadiverse country.


4.

Assertion (A): Genetic diversity is crucial for the adaptation of species to changing environmental conditions.
Reason (R): Genetic diversity allows species to evolve and adapt, ensuring their survival in varying environments.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Greater genetic variation within a species enhances its ability to adapt to environmental changes, ensuring long-term survival.


5.

Assertion (A): The Red Data Book is an important source of information about threatened species.
Reason (R): The Red Data Book categorizes species based on their risk of extinction and conservation status.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The Red Data Book tracks the conservation status of species and provides data on those that are endangered or critically endangered.


6.

Assertion (A): The IUCN (International Union for Conservation of Nature) Red List categorizes species into various threat categories.
Reason (R): The IUCN Red List helps prioritize conservation efforts by identifying species at risk.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The IUCN Red List helps determine which species are most in need of conservation efforts, based on their risk of extinction.


7.

Assertion (A): Extinction is a natural process that occurs over time.
Reason (R): Human activities like habitat destruction and overexploitation have accelerated the rate of extinction.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: While extinction is a natural phenomenon, human-induced factors have caused a dramatic increase in the rate of species extinction.


8.

Assertion (A): In-situ conservation involves protecting species in their natural habitats.
Reason (R): In-situ conservation maintains species interactions with their environment, promoting natural evolution.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: In-situ conservation occurs in the species' natural habitat, ensuring that the ecological interactions and evolutionary processes continue.


9.

Assertion (A): Ex-situ conservation refers to conservation efforts that occur outside a species’ natural habitat.
Reason (R): Ex-situ methods include botanical gardens, zoos, and seed banks, which help preserve species outside their natural environment.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Ex-situ conservation involves protecting species outside their natural habitats to prevent extinction, often in controlled environments like zoos and seed banks.


10.

Assertion (A): Protected areas like national parks and wildlife sanctuaries are critical for conserving biodiversity.
Reason (R): These areas provide safe habitats for species to thrive without human disturbance.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Protected areas help preserve ecosystems and biodiversity by minimizing human interference and offering a safe environment for wildlife.


11.

Assertion (A): Biosphere reserves are areas designated for the conservation of biodiversity at a global level.
Reason (R): Biosphere reserves conserve both the biodiversity and the traditional knowledge of local communities.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biosphere reserves are international efforts to conserve biodiversity, integrating both natural and cultural aspects, and supporting sustainable use.


12.

Assertion (A): Climate change has a significant impact on biodiversity.
Reason (R): Changes in temperature and weather patterns disrupt species’ habitats, migration routes, and reproductive cycles.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Climate change can alter ecosystems, forcing species to migrate or adapt, and sometimes leading to habitat loss and species extinction.


13.

Assertion (A): Overexploitation is a major threat to biodiversity.
Reason (R): Overhunting, overfishing, and deforestation deplete species populations and destroy habitats.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Overexploitation leads to the depletion of species and disrupts ecosystems, making it difficult for species to recover.


14.

Assertion (A): The Convention on Biological Diversity (CBD) aims to conserve biodiversity globally.
Reason (R): The CBD promotes the sustainable use of natural resources and fair sharing of benefits arising from the use of biodiversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The CBD is a treaty that promotes the conservation and sustainable use of biodiversity, and ensures equitable sharing of benefits from its use.


15.

Assertion (A): Conservation of biodiversity is essential for ecosystem services.
Reason (R): Ecosystem services like pollination, water purification, and carbon sequestration depend on biodiversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biodiversity supports the ecological functions that are critical for human survival, including essential services provided by ecosystems.


16.

Assertion (A): The World Wide Fund for Nature (WWF) plays an active role in the conservation of biodiversity.
Reason (R): WWF supports wildlife conservation, sustainable development, and environmental education worldwide.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: WWF is a global organization dedicated to conservation efforts, focusing on protecting species, habitats, and promoting sustainable practices.


17.

Assertion (A): The extinction of a species can have a cascading effect on the ecosystem.
Reason (R): The loss of one species can disrupt food webs, nutrient cycling, and ecosystem functions.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Extinction disrupts the balance of ecosystems, as species are interdependent in food chains and ecological processes.


18.

Assertion (A): Coral reefs are hotspots of biodiversity.
Reason (R): Coral reefs support a wide variety of marine species, offering shelter, food, and breeding grounds.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Coral reefs are highly diverse ecosystems that provide vital services to marine life, making them hotspots for biodiversity.


19.

Assertion (A): The concept of ecological balance is essential in biodiversity conservation.
Reason (R): Maintaining ecological balance ensures that ecosystems remain stable and that species interactions are sustainable.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Ecological balance helps maintain stability in ecosystems, promoting biodiversity and ensuring that species coexist without overpopulation or resource depletion.


20.

Assertion (A): Habitat destruction is one of the primary threats to biodiversity.
Reason (R): Human activities like deforestation, urbanization, and agriculture cause the loss and fragmentation of habitats.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Habitat destruction directly impacts biodiversity by reducing the living space for species, making it difficult for them to survive.


21.

Assertion (A): The green revolution led to an increase in agricultural productivity.
Reason (R): The green revolution introduced high-yielding varieties of crops and the extensive use of chemicals, which increased food production.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The green revolution involved the use of high-yielding crops and chemicals to increase productivity, but it also led to the loss of biodiversity due to monoculture and chemical use.


22.

Assertion (A): Sustainable development can help conserve biodiversity.
Reason (R): Sustainable development balances human needs with environmental protection, ensuring the long-term availability of natural resources.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Sustainable development ensures that resources are used responsibly without depleting them, helping to conserve biodiversity for future generations.


23.

Assertion (A): Pollination is an ecosystem service provided by biodiversity.
Reason (R): Bees, butterflies, and other pollinators facilitate the reproduction of many plant species, ensuring food production.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Pollinators are critical for the reproduction of flowering plants, and their role is essential for maintaining food production and biodiversity.


24.

Assertion (A): The study of biodiversity helps in the discovery of new medicines.
Reason (R): Many pharmaceutical drugs are derived from natural compounds found in plants, animals, and microorganisms.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biodiversity provides an immense source of natural compounds, many of which are used in the development of life-saving drugs.


25.

Assertion (A): Indigenous knowledge is important in biodiversity conservation.
Reason (R): Indigenous communities often have deep knowledge of local species and ecosystems, which aids in sustainable resource management.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Indigenous communities play a vital role in conserving biodiversity through their traditional knowledge and sustainable practices.


26.

Assertion (A): The Endangered Species Act of 1973 was enacted in the United States to protect endangered species.
Reason (R): The act provides for the identification and protection of endangered species and their habitats.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The Endangered Species Act is a key piece of legislation aimed at preventing the extinction of species through legal protection and conservation efforts.


27.

Assertion (A): The Kyoto Protocol is a legally binding international agreement to reduce greenhouse gas emissions.
Reason (R): Greenhouse gas emissions contribute to climate change, which is a major threat to biodiversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The Kyoto Protocol aims to mitigate climate change, which, if left unchecked, could lead to significant biodiversity loss.


28.

Assertion (A): Zoos and aquariums are often involved in breeding endangered species.
Reason (R): Breeding programs in controlled environments help maintain species populations, providing insurance against extinction.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Zoos and aquariums play an important role in species conservation by breeding endangered species in captivity, thereby helping to prevent extinction.


29.

Assertion (A): Reintroduction programs are used to restore species to their natural habitats.
Reason (R): Reintroduction programs help restore the population of species that have been extirpated or are endangered.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Reintroducing species into their natural habitats is an important method to increase their population and restore ecological balance.


30.

Assertion (A): Biodiversity is essential for food security.
Reason (R): Diverse crops and livestock breeds ensure the availability of nutritious food and contribute to agricultural resilience.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biodiversity provides the genetic diversity needed for stable food production and resilience against pests, diseases, and climate change.


31.

Assertion (A): Coral bleaching is caused by rising sea temperatures and pollution.
Reason (R): Coral bleaching leads to the loss of symbiotic algae in coral reefs, reducing their ability to survive.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Coral reefs are highly sensitive to temperature changes, and elevated sea temperatures and pollutants cause corals to expel the algae they rely on for nutrients, leading to bleaching.


32.

Assertion (A): The precautionary principle is a key concept in biodiversity conservation.
Reason (R): The precautionary principle advocates for preventive action when an activity threatens biodiversity, even without full scientific certainty.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The precautionary principle encourages taking action to prevent biodiversity loss when there is potential harm, even without conclusive evidence.


33.

Assertion (A): An increase in invasive species poses a threat to native biodiversity.
Reason (R): Invasive species often outcompete native species for resources, leading to their decline.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Invasive species can disrupt local ecosystems by outcompeting or preying on native species, resulting in a reduction of biodiversity.


34.

Assertion (A): Sustainable agriculture practices help conserve biodiversity.
Reason (R): Sustainable agriculture minimizes the use of harmful chemicals and promotes soil health, which supports diverse ecosystems.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Sustainable farming practices maintain soil health, reduce pollution, and preserve natural habitats, thereby conserving biodiversity.


35.

Assertion (A): Seed banks play a significant role in biodiversity conservation.
Reason (R): Seed banks store seeds of plants, allowing for the preservation of genetic diversity and restoration of ecosystems.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Seed banks help conserve plant species' genetic diversity and provide resources for restoring endangered or extinct plant populations.


36.

Assertion (A): The extinction of apex predators can cause trophic cascades.
Reason (R): The removal of apex predators disrupts the food web, affecting the abundance and distribution of other species.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Apex predators regulate populations of prey species, and their loss can lead to imbalances in ecosystems and a decline in biodiversity.


37.

Assertion (A): Ecotourism can contribute to biodiversity conservation.
Reason (R): Ecotourism provides economic incentives for local communities to conserve natural habitats while promoting awareness about environmental issues.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Ecotourism encourages the conservation of biodiversity by generating revenue for local communities and fostering environmental education.


38.

Assertion (A): The ecosystem approach to conservation focuses on protecting entire ecosystems rather than individual species.
Reason (R): Ecosystems are composed of many interdependent species and environmental factors, making them crucial to biodiversity conservation.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Focusing on ecosystems helps conserve multiple species at once and preserves the processes that maintain biodiversity.


39.

Assertion (A): Habitat fragmentation is one of the primary causes of biodiversity loss.
Reason (R): Fragmented habitats isolate populations, reducing gene flow and increasing the risk of inbreeding.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Fragmentation reduces connectivity between habitats, which can lead to isolated populations with limited genetic diversity and increased vulnerability to extinction.


40.

Assertion (A): Agroforestry integrates trees into agricultural landscapes, helping to conserve biodiversity.
Reason (R): Agroforestry practices improve soil quality, enhance water retention, and provide habitats for a variety of species.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Agroforestry contributes to biodiversity conservation by promoting ecosystem services that benefit both agriculture and wildlife.


41.

Assertion (A): The concept of ecosystem services recognizes the importance of biodiversity for human well-being.
Reason (R): Ecosystem services include benefits such as clean air, water, food, and climate regulation, all of which are essential for human life.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Ecosystem services provided by biodiversity are fundamental to human survival and quality of life, reinforcing the need for conservation.


42.

Assertion (A): The Convention on Biological Diversity (CBD) aims to conserve biodiversity globally.
Reason (R): The CBD promotes international cooperation to ensure the sustainable use and fair distribution of genetic resources.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The CBD provides a framework for global action to conserve biodiversity and ensures that the benefits derived from genetic resources are shared equitably.


43.

Assertion (A): The term "biodiversity hotspot" refers to regions with high species richness.
Reason (R): Hotspots are areas that are both rich in species and threatened by human activities, making them priorities for conservation.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biodiversity hotspots are critical areas that require urgent attention for conservation due to their unique species and the threats they face.


44.

Assertion (A): Biodiversity increases ecosystem stability.
Reason (R): A diverse ecosystem is more resilient to disturbances such as diseases, climate change, and natural disasters.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Ecosystems with high biodiversity are better able to recover from disturbances, maintaining stability and essential functions.


45.

Assertion (A): The IUCN Red List categorizes species based on their conservation status.
Reason (R): The Red List provides a global assessment of species at risk of extinction, helping to prioritize conservation efforts.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: The IUCN Red List classifies species according to their extinction risk, guiding conservation priorities.


46.

Assertion (A): Urbanization often leads to a decrease in biodiversity.
Reason (R): Urbanization leads to habitat destruction, pollution, and the introduction of invasive species, all of which negatively impact biodiversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Urbanization disrupts ecosystems by replacing natural habitats with built environments, thereby reducing biodiversity.


47.

Assertion (A): Biodiversity conservation is essential for human health.
Reason (R): Many medicines, food sources, and ecosystem services are directly derived from biodiversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Biodiversity provides resources for human health, including medicinal plants, food, and ecosystem functions like disease regulation.


48.

Assertion (A): The loss of biodiversity can exacerbate climate change.
Reason (R): Biodiversity loss disrupts ecosystems that play key roles in carbon sequestration, water regulation, and climate stabilization.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Healthy ecosystems contribute to climate regulation, and their loss can worsen climate change impacts.


49.

Assertion (A): Ecological corridors help in biodiversity conservation.
Reason (R): Ecological corridors connect fragmented habitats, allowing species to move and maintain genetic diversity.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Ecological corridors are essential for species movement, gene flow, and maintaining biodiversity across fragmented landscapes.


50.

Assertion (A): Reducing the human population can help conserve biodiversity.
Reason (R): A smaller human population reduces the demand for natural resources, helping to preserve ecosystems.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Explanation: Reducing human consumption and population growth can lessen the pressure on ecosystems, thereby aiding biodiversity conservation.