Ncert Solutions for Class 12 Biology Chapter 13 Biodiversity and Conservation

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Biodiversity and Conservation ncert solutions: Class 12th biology chapter 13 ncert solutions

TextbookNCERT
ClassClass 12
SubjectBiology
ChapterChapter 13
Chapter NameBiodiversity and Conservation class 12 ncert solutions
CategoryNcert Solutions
MediumEnglish

Are you looking for Ncert Solutions for Class 12 Biology Chapter 13 Biodiversity and Conservation? Now you can download Ncert class 12 biology chapter 13 questions and answers pdf from here.

Question 1: Name the three important components of biodiversity.

Solution 1: The three important components of biodiversity are:

Ecosystem Diversity: This involves the variety of ecosystems in a given area, including the different habitats, communities, and ecological processes. Ecosystem diversity is vital for providing ecosystem services, such as clean air and water, pollination, and climate regulation.

Genetic Diversity: This refers to the variety of genes within a species. Genetic diversity is essential for a population’s ability to adapt to changing environments, resist diseases, and maintain overall health.

Species Diversity: This encompasses the variety of species within a given ecosystem or on Earth as a whole. Species diversity includes not only the number of species (richness) but also their relative abundance (evenness) within ecosystems.

Question 2: How do ecologists estimate the total number of species present in the world?

Solution 2: The total number of species present in the world is calculated by ecologists by statistical comparison between a species richness of a well-studied group of insects of temperate and tropical regions and these ratios are extrapolated with other groups of plants and animals to calculate the total species richness present on the Earth.
According to an estimate by researchers, it is about seven million which seems to be the variety of living organism present on the earth is very vast.

Question 3: Give three hypotheses for explaining why tropics show greatest levels of species richness.

Solution 3: There are three different hypotheses proposed by scientists for explaining species richness in the tropics.

Climate Stability Hypothesis: The tropics have relatively stable climates with consistent temperatures and abundant rainfall year-round. This stability allows for longer periods of evolutionary development and diversification, supporting a greater number of species.

Productivity Hypothesis: Tropical regions typically have high primary productivity due to ample sunlight and moisture. This increased availability of resources supports larger populations and more complex food webs, which can lead to greater species diversity.

Area and Habitat Diversity Hypothesis: The tropics encompass vast areas with diverse habitats (e.g., rainforests, coral reefs, savannas). This variety of ecological niches allows for more species to coexist, as different species can adapt to and exploit different resources within these varied environments.

Question 4: What is the significance of the slope of regression in a species – area relationship?

Solution 4: Slope of regression or regression coefficient makes it easier to measure species richness along an area. For a limited area like, a country, it gives a constant value of 0.1 to 0.2 irrespective of the taxonomic group or region. It remains amazingly similar for all those small regions. On the contrary, for measuring species-area relationship over large areas like the entire continents, the slope of regression values in the range of 0.6 to 1.2.

Question 5: What are the major causes of species losses in a geographical region?

Solution 5: The major causes of species losses in a geographical region include:

Fragmentation: Breaking up habitats into smaller, isolated patches reduces the ability of species to migrate, find mates, and access resources, negatively impacting populations.

Habitat Destruction: Urbanization, deforestation, and land conversion for agriculture lead to the loss of natural habitats, making it difficult for species to survive.

Climate Change: Alterations in temperature and precipitation patterns can disrupt ecosystems and species’ life cycles, leading to habitat loss and increased extinction risks.

Invasive Species: Non-native species can outcompete, prey on, or introduce diseases to native species, significantly reducing their populations and leading to declines.

Pollution: Contaminants in air, water, and soil can harm species directly and degrade habitats, affecting biodiversity.

Overexploitation: Unsustainable hunting, fishing, and harvesting can deplete species populations faster than they can reproduce, leading to declines and extinctions.

Question 6: How is biodiversity important for ecosystem functioning?

Solution 6: Biodiversity is important for ecosystem functioning because,

(1) It contributes to productivity.
(2) It cause more efficient recycling of energy and matter.
(3) It has many alternative pathways for survival under diverse conditions.
(4) Rich biodiversity provides alternatives available at each trophic level.

All organisms are linked in food chains and interact with their abiotic environment in such a way so as to keep the natural cycles going and make the ecosystems self – sustaining units. Disappearance of any link in a food chain will not affect the ecosystem as other alternatives are there.

Question 7: What are sacred groves? What is their role in conservation?

Solution 7: Sacred Groves are patches of forest or natural vegetation that are protected and preserved by local communities due to their cultural, spiritual, or religious significance. These groves are often associated with specific deities, ancestral spirits, or traditional beliefs and practices. acred groves are found in Rajasthan, Western Ghats of Karnataka,and Maharashtra, Meghalaya, and Madhya Pradesh.

Sacred groves help in the protection of many rare, threatened, and endemic species of plants and animals found in an area. The process of deforestation is strictly prohibited in this region by tribals. Hence, the sacred grove biodiversity is a rich area. 

Question 8: Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?

Solution 8: Biotic components of an ecosystem, particularly plants, play a crucial role in controlling floods and soil erosion. The roots of plants bind soil particles together, which prevents the topsoil from being eroded by wind or surface runoff. This root structure also enhances soil porosity, allowing water to infiltrate the ground, which helps in groundwater recharge and reduces surface runoff, thereby mitigating flood risks. Additionally, healthy plant cover increases soil fertility and biodiversity, further contributing to ecosystem stability.

Ecosystem services provided by these biotic interactions include the purification of water, habitat provision for wildlife, retention of water to combat floods and droughts, and maintenance of the carbon-oxygen balance. Overall, plants are essential in maintaining soil integrity and protecting against natural disasters, while also supporting various ecological functions.

Question 9: The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?

Solution 9: The greater species diversity of animals (72 percent) compared to plants (22 percent) can be attributed to several factors. Firstly, animals generally exhibit more complex behaviors and interactions within ecosystems, leading to a wider variety of ecological niches and evolutionary pathways.

For example, animals can occupy various roles as predators, prey, decomposers, and pollinators, allowing for greater specialization and adaptation to different environments. Secondly, animals have shorter generation times and higher mobility, which can facilitate faster evolutionary changes and diversification compared to plants.

This mobility enables them to exploit new habitats and resources more readily, leading to speciation. Additionally, the dynamic interactions between animals, such as competition and predation, can drive evolutionary pressures that promote diversification. In contrast, plant diversification can be limited by factors such as reliance on specific pollinators and slower dispersal mechanisms, which can restrict gene flow and adaptability.

Question 10: Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

Solution 10: Yes, there are various kinds of parasites and disease-causing microbes that we deliberately want to eradicate from the Earth. Since these micro-organisms are harmful to human beings, scientists are working hard to fight against them.

Scientists have been able to eliminate small pox virus from the world through the use of vaccinations. This shows that humans deliberately want to make these species extinct. Several other eradication programmes such as polio and Hepatitis B vaccinations are aimed to eliminate these disease-causing microbes.

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