NCERT Solutions For Class 12 Biology Chapter 13 Biodiversity And Conservation

Access NCERT Solution for Class 12 Biology Chapter 13 - Biodiversity and Conversation

1. Name the three important components of biodiversity.
   The three main parts of biodiversity are genetic, species, and ecosystem diversity.
   
   • Genetic diversity: The variety of genes within a species.
   • Species diversity: The number of different species in an area.
   • Ecosystem diversity: The variety of habitats, communities, and ecological processes in the biosphere.
2. How do ecologists estimate the total number of species present in the world?
   Ecologists use comparison and statistics to guess how many species exist.
   
   • They count the known species in well-studied groups like insects.
   • They compare these numbers between tropical and temperate regions.
   • Ratios from these comparisons help estimate numbers in less studied groups.
   • Scientists have estimated about seven million species on Earth using these methods.
3. Give three hypotheses for explaining why tropics show greatest levels of species richness.
   The tropics have the most species for these reasons:
   
   • More solar energy reaches the tropics, so there is more productivity and diversity.
   • The environment is more stable with less seasonal change, which supports many species.
   • Tropical regions were less disturbed during the ice ages, so more species survived there.
4. What is the significance of the slope of regression in a species-area relationship?
   The slope shows how quickly species number increases with area.
   
   • The slope is shown by 'z' in the equation S = CA^z.
   • The slope (z) tells us the rate at which species number grows with area.
   • For small areas, the value is often similar across regions and groups.
   • For large areas (like continents), the slope becomes much steeper.
   • This means bigger places support more new species as the area grows.
5. What are the major causes of species losses in a geographical region?
   Human actions are mainly responsible for species loss.
   
   • Habitat loss and fragmentation: Cutting and dividing natural areas makes it hard for species to survive.
   • Over-exploitation: Using resources too much, like overfishing or deforestation.
   • Alien species invasions: Introducing new species that harm local plants and animals.
   • Co-extinction: When an animal or plant dies out because something it depends on is lost.
6. How is biodiversity important for ecosystem functioning?
   More kinds of species help ecosystems work better and stay stable.
   
   • High biodiversity keeps ecosystems stable under different conditions.
   • It helps ecosystems recover from troubles like floods or invasive species.
   • All organisms in food chains are connected; more species means fewer gaps in those chains.
   • Biodiversity supports clean air, water, healthy soil, and balanced life.
7. What are sacred groves? What is their role in conservation?
   Sacred groves are forest patches protected for religious reasons.
   
   • These areas are usually near temples and are not disturbed or cleared.
   • Sacred groves are found in parts of India like Rajasthan, Western Ghats, Meghalaya, and Madhya Pradesh.
   • They protect rare, endangered, and unique plants and animals.
   • Local communities prevent cutting or harming the plants in these groves.
8. Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
   Plants and animals help stop floods and soil loss.
   
   • Plant roots hold soil in place, stopping it from being washed or blown away.
   • Roots make soil more open and absorb water, reducing flooding.
   • Leaves shield the soil surface from heavy rain.
   • Animals like earthworms mix and aerate the soil, keeping it healthy.
   • Together, living creatures help keep soil fertile and safe from disasters.
9. The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations for how animals achieved greater diversification?
   Animals are more diverse because they adapt to many places and conditions.
   
   • Animals, especially insects, developed complex nervous systems for sensing and responding to changes.
   • They can move, helping them find new places and escape danger.
   • Arthropods have hard exoskeletons that protect them and allow more types to evolve.
   • Animals' body structures let them survive in more habitats than most plants.
10. Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
    Sometimes, we try to wipe out harmful species like disease germs.
    
    • Examples are viruses or bacteria that cause diseases.
    • Scientists worked hard to eliminate smallpox by vaccination.
    • We use vaccines to try removing other disease-causing microbes like polio or Hepatitis B.
    • This protects human health, which is why such species are targeted for extinction.
11. How to differentiate biodiversity and biodiversity conservation?
    Biodiversity is the variety of life; conservation is protecting that variety.
    
    • Biodiversity: All forms of life in an area or on Earth, including their differences and ecosystems.
    • It gives us food, clean air, water, and medicine.
    • Biodiversity conservation: The act of saving, managing, and protecting those living things and their homes.
    • The aim is to keep nature’s balance and protect endangered species.
    • Simply, biodiversity shows all life; conservation is caring for it.

What You’ll Learn from Biodiversity and Conservation Class 12 NCERT Solutions

• You’ll see why biodiversity is essential for healthy ecosystems and life on Earth.
• Understanding the main reasons for loss of biodiversity helps you answer exam questions better.
• Know how in-situ and ex-situ methods work to conserve plants and animals.
• This chapter explains species-area relationships, sacred groves, and ecosystem services simply.
• Download the Biodiversity and Conservation ncert pdf to get all Class 12 Biology Chapter 13 question answers in clear steps.