NCERT Questions for Class 12 Biology Chapter 13 – Biodiversity and Conservation

Important Questions with Solutions of Class 12 Biology Chapter 13 – Biodiversity and Conservation

Short Answer Questions

1) Ecologists have estimated that the value of Z lies between 0.1 and 0.2, irrespective of taxonomic category or geographic region. At what stage in a species-area relationship would the slope of the line become steeper?

Ans – Ecologists have calculated that the value of Z, irrespective of taxonomic group or geographic area is between 0.1 and 0.2; the slope of the line is much steeper when analyzing the species-area relationship at large spatial scales, for example whole continents.

2) Cryopreservation definition. Why do you consider it as an important technique for conservation of biodiversity?

Ans – Cryopreservation is the preservation technique in which the material is preserved at -196°C using liquid nitrogen. It is helpful for conserving biodiversity since it can keep endangered species alive and healthy for a longer period.

3) State two forms of ex-situ conservation traditionally used.

Ans – Two forms of ex-situ conservation traditionally used are the botanical gardens and zoological parks.

4) What are the national parks for rhinoceroses and lions in India?

Ans – The national park for rhinoceros is Kaziranga National Park and the national park for lions is Gir National Park.

5) Explain co-extinction with an example.

Ans – Co-extinction refers to the likely extinction of one species of plant or animal along with that of another. Plant-pollinator mutualism, for instance.

6) Why is the species diversity of plants much less than that of animals?

Ans – Because most animals have neurological systems that regulate and coordinate various functions of the animal, the species diversity of plants is much lower than that of animals. Moreover, they possess receptors for external stimuli, and some of those reactions are adaptive which ensures an organism’s survival in a fluctuating environment.

7) What are the sacred groves? What is their role in conservation?

Ans – Sacred groves are the forested regions near any worship site and nobody of the community can cut any of the tree branch of sacred groves, so many wild and native species grows in this region.

8) Describe biodiversity? What has been responsible for its recent importance?

Ans – Biodiversity refers to the heterogeneity among the living organisms coming out from the earth, marine, and other types of aquatic ecosystem. Diversity exists within a species, between species, and between species in different types of ecosystems. Industrialization, civilization, and urbanization were found to be making the maximum exploitation of all varieties of plants and animals in the modern civilization, causing threats to many organisms and emphasizing the significance of biodiversity in present days.

3 mark questions

1) What are the special circumstances that may explain why the tropics have such exceptionally high biological richness?

Ans – The special feature of the tropics that may explain why they have such elevated biological richness is as follows:

• Speciation is time-dependent; in contrast to temperate regions that have seen repeated glaciations, tropical latitudes have stayed relatively stable for millions of years, allowing for extensive evolutionary opportunities for species diversity.
• In habitats, there is often less seasonality, higher constancy and enhanced predictability in tropical locations.
• Abundance of solar energy in the tropical region results in maximum productivity that is related to enhanced biodiversity.

2) What is the importance of conserving biodiversity?

Ans – Reasons for protecting biodiversity can be categorised into three groups.

• Narrow Utilitarian Reasons: Numerous economic advantages have been obtained by humanity. The advantages include food, fibre, fuel, industrial goods, and medical products.
• General Utilitarian Justifications: Biodiversity significantly contributes to the provision of ecosystem services such as:
  • Oxygen production
  • Pollination of flowers, which is essential for the production of seeds and fruits.
  • Aesthetic experiences include avian observation, admiring spring blossoms, traversing dense woodlands, and engaging with the melody of the bulbul, among others.
• Ethical Reasons: All species, regardless of their economic benefit to humans, have inherent worth. We possess a moral obligation to ensure their well and to transmit the biological legacy to future generations.

3) What is the correlation between species richness and area? What is the importance of the regression slope?

Ans – Alexander Von Humboldt discovered that within a region, species richness increases with the examined area, but only up to a certain limit; consequently, the relationship between species richness and area for various taxa is regarded as a rectangular hyperbola. On a logarithmic scale, the relationship becomes linear and is represented by the law equation:

Log S = Log C + Z Log A

The regression slope values are consistent across different taxonomic groups and regions. When such analyses are conducted among species spanning extensive regions, the regression slope will be significantly steeper.

4) What are the various strategies for biodiversity conservation in India?

Ans – In India, there are two primary methodologies for biodiversity conservation. They are as follows:

• In-situ Conservation: The procedure involves safeguarding endangered plant or animal species within their natural habitats, either through habitat preservation or restoration, or by defending these species from predators. It comprises:
  • Biosphere Reserves: There are 425 biosphere reserves globally, with 14 located in India. Areas of significance have been designated for optimal conservation of endemic or endangered species.
  • National Parks and Wildlife Sanctuaries: India comprises around 90 national parks and 448 wildlife sanctuaries.
  • Sacred Forests: These are pristine forests devoid of human interference, encircled by severely damaged landscapes.
• Ex-situ Conservation: This refers to the method of safeguarding endangered plant or animal species by relocating them from their threatened habitats to human-managed environments. It comprises:
  • Botanical gardens, zoological parks, and arboreta are traditional techniques of ex-situ conservation.
  • Cryopreservation refers to the storage of materials at ultra-low temperatures, achieved either through rapid cooling or progressive cooling accompanied by concomitant dehydration at low temperatures.

5) Provide a detailed overview of biodiversity in India.

Ans –

• India is in the top 10 mega-biodiversity nations globally, attributed to its varied climatic conditions and ecological habitats, which encompass tropical, subtropical, and temperate zones.
• India hosts approximately 47,000 plant species and 81,000 animal species.
• Although comprising about 2-4% of the Earth’s terrestrial expanse, India accounts for 10-35% of global biodiversity.
• India is home to a substantial variety of indigenous species, comprising 5,000 species of flowering plants across 141 genera and 47 families that are endemic to the region.
• India exhibits significant endemism, with 62% of amphibian species and 50% of lizard species being endemic, particularly in the Western Ghats.
• India is the source of 166 kinds of crop plants and 320 species of wild relatives of cultivated crops.
• India possesses abundant maritime life, featuring a coastline of 7,500 kilometres.
• India contains two of the world’s 25 biodiversity hotspots: the Western Ghats and the Eastern Himalayas.

5 Marks Questions

1) What is the significance of the nickname ‘The Evil Quartet’ in relation to biodiversity? Identify the members of this quartet. What is the reason for mourning the genetic material with the extinction of a species?

Ans – The phrase ‘Evil Quartet’ denotes the factors contributing to biodiversity loss. The quartet comprises the following members:

1. Habitat loss and fragmentation: Various human activities result in the division of extensive habitats into smaller parts, adversely impacting species that require wide territories, such as elephants and birds, leading to a drop in their populations.
2. Over-Exploitation: The transformation of necessity into avarice for a resource. The overexploitation of passenger pigeons resulted in their extinction. Marine fish are nearing endangerment owing to overexploitation.
3. Invasion of Alien Species: The introduction of a species, whether purposeful or unintentional, to a nearby area may disrupt the equilibrium of existing species. For instance, Eichhornia, following its introduction, presented a significant threat to indigenous species.
4. Co-extinction: The extinction of one species inevitably results in the extinction of another when their association is obligatory. For instance, when a host species becomes extinct, the obligatory parasites reliant on it also perish.

We mourn the loss of genetic diversity when a species becomes extinct, as wild variants exhibit resilience and enhanced resistance to pathogens, proving advantageous in crop breeding initiatives.

2) Identify a minimum of two methodologies for ex-situ conservation and two methodologies for in-situ conservation as strategies for biodiversity preservation.

Ans – The two approaches for biodiversity conservation, namely in-situ and ex-situ conservation, are as follows:

In situ conservation:

1. Identification and optimal protection must be afforded to ‘hot spots.’
2. Legal safeguarding for ecologically diverse regions.
3. Biosphere reserves, national parks, and wildlife sanctuaries.
4. Sacred groves.

Ex-situ Conservation:

1. Establishment of zoological parks, botanical gardens, and a wildlife refuge.
2. Cryopreservation
3. Seed repository.