ROUTERA


Chapter 15 Biodiversity and its conservation

Class 12th Biology Chapter Case Study


Case Study 1: The Importance of Biodiversity in Ecosystems

Biodiversity refers to the variety and variability of life forms, including plants, animals, and microorganisms, present in an ecosystem. A high level of biodiversity is essential for ecosystem stability, resilience, and functioning. In a forest ecosystem, various species of trees, plants, herbivores, carnivores, and decomposers interact with one another, forming complex food webs. These interactions support processes like nutrient cycling, pollination, and water purification. However, when biodiversity is reduced, the ecosystem becomes more vulnerable to disturbances such as climate change, invasive species, or diseases.

Questions:

  1. The primary benefit of maintaining high biodiversity in an ecosystem is:

    • A) To promote genetic uniformity
    • B) To reduce species interactions
    • C) To ensure ecosystem stability and resilience
    • D) To decrease ecosystem complexity

    Answer: C) To ensure ecosystem stability and resilience

  2. In a forest ecosystem, the process of pollination is essential for:

    • A) Nutrient cycling
    • B) Reproduction of plants
    • C) Energy transfer between trophic levels
    • D) Water purification

    Answer: B) Reproduction of plants

  3. Decomposers in an ecosystem contribute to:

    • A) The production of oxygen
    • B) The breakdown of dead organic material and recycling of nutrients
    • C) The stabilization of herbivore populations
    • D) The absorption of sunlight

    Answer: B) The breakdown of dead organic material and recycling of nutrients

  4. A decrease in biodiversity in an ecosystem can result in:

    • A) Increased resilience to disturbances
    • B) Greater ecosystem stability
    • C) Loss of ecosystem services such as pollination and water purification
    • D) Higher species richness

    Answer: C) Loss of ecosystem services such as pollination and water purification


Case Study 2: Threats to Biodiversity: Habitat Loss and Fragmentation

Human activities such as deforestation, urbanization, and agriculture lead to habitat loss and fragmentation. As forests are cleared for agricultural purposes or infrastructure development, the natural habitats of many species are destroyed. This reduces the area available for species to live and reproduce. Fragmentation of habitats often leads to smaller, isolated populations that have a higher risk of extinction due to inbreeding, loss of genetic diversity, and inability to migrate for resources.

Questions:

  1. Habitat fragmentation results in:

    • A) Larger populations with higher genetic diversity
    • B) Isolated populations with increased risk of extinction
    • C) Enhanced migration and gene flow
    • D) Increased species richness and diversity

    Answer: B) Isolated populations with increased risk of extinction

  2. Deforestation, as a major cause of habitat loss, leads to:

    • A) Increased biodiversity
    • B) Increased availability of resources for species
    • C) Destruction of species' natural habitats
    • D) Greater migration routes for species

    Answer: C) Destruction of species' natural habitats

  3. One of the consequences of habitat fragmentation is:

    • A) Improvement in the genetic diversity of populations
    • B) Isolation of species, leading to smaller populations
    • C) Increased availability of resources for all species
    • D) Creation of continuous, large habitats

    Answer: B) Isolation of species, leading to smaller populations

  4. Inbreeding depression is a common issue in small, isolated populations because:

    • A) It increases the genetic variation
    • B) It decreases the genetic diversity
    • C) It leads to stronger, healthier populations
    • D) It promotes species migration

    Answer: B) It decreases the genetic diversity


Case Study 3: Conservation Strategies – Protected Areas and Sanctuaries

Protected areas such as national parks, wildlife sanctuaries, and biosphere reserves are vital tools for biodiversity conservation. These areas are designated to safeguard wildlife and plant species, preventing habitat destruction and promoting species survival. Additionally, biosphere reserves aim to balance conservation efforts with sustainable development. These reserves often include core zones, buffer zones, and transition zones, which help in the management and protection of biodiversity while also allowing for controlled human activity.

Questions:

  1. National parks and wildlife sanctuaries are primarily established to:

    • A) Promote tourism and recreation
    • B) Protect biodiversity and prevent habitat destruction
    • C) Encourage agricultural activities
    • D) Increase urban development

    Answer: B) Protect biodiversity and prevent habitat destruction

  2. Biosphere reserves differ from national parks and wildlife sanctuaries because they:

    • A) Are only meant for recreational activities
    • B) Allow controlled human activities along with conservation
    • C) Do not protect endangered species
    • D) Are less diverse in terms of species

    Answer: B) Allow controlled human activities along with conservation

  3. A core zone in a biosphere reserve is:

    • A) A zone where human activities are allowed for sustainable development
    • B) A zone where human activities are strictly prohibited to protect biodiversity
    • C) A zone where agriculture is practiced
    • D) A zone with high levels of pollution

    Answer: B) A zone where human activities are strictly prohibited to protect biodiversity

  4. The transition zone in a biosphere reserve is characterized by:

    • A) Strict protection of wildlife with no human activity
    • B) A high level of urbanization
    • C) Controlled human activity that supports sustainable development
    • D) Total destruction of habitats

    Answer: C) Controlled human activity that supports sustainable development


Case Study 4: Endangered Species and Conservation Efforts

Many species, including the Bengal tiger, Indian rhinoceros, and Asiatic lion, are classified as endangered due to habitat loss, poaching, and climate change. Conservation efforts such as the establishment of protected areas, anti-poaching laws, and captive breeding programs have been implemented to prevent their extinction. The Bengal tiger, for instance, is the focus of various conservation programs in India, aimed at increasing its population through protected areas like the Sundarbans and Project Tiger.

Questions:

  1. The Bengal tiger is considered an endangered species due to:

    • A) Overpopulation in protected areas
    • B) Habitat loss, poaching, and human-wildlife conflict
    • C) Overabundance of prey species
    • D) Migration to other countries

    Answer: B) Habitat loss, poaching, and human-wildlife conflict

  2. Project Tiger is a conservation program aimed at:

    • A) Increasing the population of Bengal tigers in the wild
    • B) Captive breeding of tigers for tourism purposes
    • C) Eliminating all predators in tiger habitats
    • D) Creating more human settlements in tiger reserves

    Answer: A) Increasing the population of Bengal tigers in the wild

  3. Captive breeding programs for endangered species are designed to:

    • A) Increase genetic diversity in the wild
    • B) Allow animals to be kept in zoos indefinitely
    • C) Maintain a population of species in controlled environments to later reintroduce them into the wild
    • D) Increase the profit from endangered species

    Answer: C) Maintain a population of species in controlled environments to later reintroduce them into the wild

  4. The Asiatic lion, a species once on the brink of extinction, has been the focus of conservation efforts primarily in:

    • A) The Sundarbans
    • B) Gir Forest National Park
    • C) Kaziranga National Park
    • D) Jim Corbett National Park

    Answer: B) Gir Forest National Park


Case Study 5: Global Biodiversity Hotspots

A biodiversity hotspot is a biogeographic region that is both a significant reservoir of biodiversity and is threatened with destruction. The Western Ghats and Sundaland are examples of biodiversity hotspots, which contain numerous endemic species and face high rates of habitat destruction. These areas are of global significance, and conservation efforts focus on protecting their unique flora and fauna from the impacts of deforestation, agriculture, and urbanization.

Questions:

  1. A biodiversity hotspot is defined as:

    • A) A region with low species diversity and minimal threats
    • B) A region that is rich in endemic species and is threatened with habitat destruction
    • C) A region with only endangered species
    • D) A region where all species are protected

    Answer: B) A region that is rich in endemic species and is threatened with habitat destruction

  2. The Western Ghats is considered a biodiversity hotspot because it:

    • A) Has a low level of endemic species
    • B) Contains numerous species that are found nowhere else on Earth
    • C) Has been heavily urbanized with little conservation effort
    • D) Lacks significant species diversity

    Answer: B) Contains numerous species that are found nowhere else on Earth

  3. The primary threat to biodiversity in hotspots like the Western Ghats is:

    • A) High levels of genetic diversity
    • B) Habitat destruction due to deforestation and human activities
    • C) Overpopulation of endemic species
    • D) Protection from human settlements

    Answer: B) Habitat destruction due to deforestation and human activities

  4. Conservation efforts in biodiversity hotspots generally focus on:

    • A) Expanding human settlements
    • B) Protecting the unique species and their habitats from destruction
    • C) Promoting tourism for economic gain
    • D) Deforestation to create agricultural land

    Answer: B) Protecting the unique species and their habitats from destruction