Get summaries, questions, answers, solutions, notes, extras, PDF and guides for Chapter 4 Loss of Biodiversity and its Conservation: NBSE Class 12 Environment (Environmental Education) textbook, which is part of the syllabus of students studying under the Nagaland Board. These solutions, however, should only be treated as references and can be modified/changed.
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Summary
Many species of plants and animals are disappearing faster than before. This is happening because of more people, cutting down forests, pollution, and hunting. Long ago, only one species would disappear in ten years. Now, many species are lost every year. This is dangerous because when one species disappears, the balance of nature is disturbed. If too many disappear, the Earth’s systems could stop working properly. Studies show that one in every eight plant species is at risk of disappearing forever.
The main reasons for the loss are actions by people. Clearing forests for farming or buildings, polluting air and water, hunting animals for trade, and bringing new animals or plants from other places all hurt local species. For example, water hyacinth spreads quickly in ponds and does not let other plants grow. Animals like rhinos and elephants are hunted for their horns and tusks. Roads also harm animals when vehicles hit them. Sometimes, birds and fish stop migrating because their paths are blocked. Natural disasters like floods and earthquakes also cause local extinctions.
Some animals and plants live in only one place. If that place is destroyed, they vanish forever. These are called endemic species. Some species are already very few in number and may become extinct soon. These are called endangered species.
To protect biodiversity, there are two ways: in-situ and ex-situ conservation. In-situ means saving species in their natural homes like forests, national parks, and sanctuaries. These places keep the animals and plants safe. It is cheaper and helps many unknown species too. But this method needs a lot of space.
Ex-situ means taking animals and plants out of their homes and keeping them safe in zoos, gardens or labs. This helps when the natural home is already destroyed. It helps protect rare species, and people can take care of them better. But it does not always work because these animals may not survive if sent back to the wild.
To protect nature, we must also plant more trees, stop using too much forest land, and grow food without harming the soil. People should learn more about saving wildlife. New farming and forestry methods must help both people and nature. Technology is also helping with breeding and saving species.
Textbook solutions
Short Answer Questions
1. What is in-situ conservation? Define.
Answer: In-situ conservation means the conservation of a species in its natural habitat or natural ecosystem, or even in an artificial ecosystem. It involves the conservation of species in places where the species normally occur. The natural surroundings or the entire ecosystem is protected and maintained so that all the constituent species, known or unknown, are conserved and benefited. The main point of in-situ conservation is the establishment of protected areas. It is defined as the conservation of species within a natural ecosystem.
2. Give two reasons for loss of biodiversity.
Answer: Two reasons for the loss of biodiversity are, firstly, human activities, in particular, the destruction of plants and animals, which includes the destruction of habitats and fragmentation. Secondly, population explosion, which leads to growing demands that have an adverse effect on the environment, leading to the destruction of natural resources and extinction of species……….
3. What is Red Data Book?
Answer: A Red Data Book is a book listing threatened and endangered species and subspecies. On the basis of degree of threat, 8 Red List categories have been identified in the Red Data Book by the International Union for Conservation of Nature and Natural Resources (IUCN Switzerland).
4. Define ex-situ conservation.
Answer: Ex-situ conservation is the conservation of endangered species away from their natural habitats. It is done under human supervision and constant human care.
5. List strategies of ex-situ conservation.
Answer: The strategy of ex-situ conservation involves the identification of species to be conserved and the methods of ex-situ conservation. The methods or techniques, which are essentially meant to maintain, multiply, or help the species to survive, include:
i. Long-term captive breeding and propagation, usually undertaken for species which have lost their habitats permanently or face extinction due to certain factors in their habitat.
ii. Short-term propagation and release of animals in their natural habitat, resorted to when a species’ population declines due to temporary setbacks.
iii. Animal translocation, which is the release of animals in a new locality, different from where they were captured, often involving a period of captivity.
iv. Animal reintroduction, which may involve the rehabilitation of species, by releasing animals born or raised in captivity.
v. The use of advanced technology in the service of endangered species, including aspects like chemical immobilisation and anaesthesia, nutrition, maintenance and health care of animals, identification, data collection and information technology, and advances in reproductive technology such as artificial insemination and cryopreservation.
6. What are vulnerable species?
Answer: Vulnerable species are those species that may go to the endangered category in the near future if the causal factors continue operating.
7. Write the names of most wanted species recognised by WWW.
Answer: The 10 most wanted species announced by WWW in 2004 are Humphead wrasse, Tigers, Ramin, Great white sharks, Irrawady dolphins, Asian elephants, Pig-nosed turtles, Yellow-crested cockatoos, Leaf-tailed gackos, and Asian yew trees.
8. Write the names of some international organisations which are working on conservation of biodiversity.
Answer: Some of the international organizations working on the conservation of biodiversity are the World Resource Institute (WRI), the International Union for the Conservation of Nature and Natural Resources (IUCN), the United Nations Environment Programme (UNEP), and the World Wildlife Fund for Nature (WWF).
9. What is a hot spot?
Answer: The most threatened ones as well as the areas of mega-diversity are known as hot spots.
Long Answer Questions
1. What is the method of ex-situ conservation?
Answer: The methods of ex-situ conservation involve techniques essentially meant to maintain, multiply, or help species survive under natural conditions. These include:
- Long-term captive breeding and propagation, which is usually undertaken for species that have lost their habitats permanently or where certain factors in the habitat shall force them to extinction. Most of the time, human interests such as poaching, excessive hunting, etc., pose a threat to the existence of species’ long-term maintenance. Captive breeding is the only way to preserve species which are housed in zoos and botanical gardens, as most of such species shall not survive in their wild habitats. For example, Przewalski’s horse (Equus przewalskii) is regularly maintained and bred in captivity.
- Short-term propagation and release of the animals in their natural habitat, a method resorted to when the population of a species declines due to some temporary setback in their living conditions. The endangered animals maintained and bred in captivity under human care are subsequently released in a wild habitat.
- Animal translocation, which is the release of animals in a new locality that come from somewhere else other than the place in which they are being released. The capture, transfer, and release of animals from one locality to another usually involves maintenance of the animal in captivity for some time.
- Animal reintroduction, which may involve rehabilitation of the species. It is the release of animals either born in captivity or caught in infancy and grown in captivity, which had either declined or disappeared as a result of human pressure or some natural causes like epidemic, etc.
- Advanced technology in the service of endangered species. Today, a large number of species have been classified as threatened to the extent that sincere human care and ex-situ management is the only way to preserve them. For the past twenty years, advanced science and technology has greatly extended the effectiveness of the methodology of ex-situ conservations. This includes chemical immobilisation and anaesthesia; nutrition, maintenance, and health care of animals; identification, data collection, and information technology; and advances in reproductive technology like artificial insemination, embryo transfer technology, and cryopreservation of gametes and embryos.
2. Discuss the advantages and disadvantages of in-situ conservation.
Answer: In-situ conservation of wildlife offers many advantages. The method involves the promotion of a natural system to take care of itself; we simply provide conditions to let life forms do it themselves.
The advantages are as follows:
- It is the best strategy for long-term protection of biodiversity.
- In-situ conservation is a cheap and convenient way of conserving biological diversity as we play a supportive role only. Factors detrimental to the existence of the species concerned are eliminated, and the species is allowed to grow in its natural environment in which it has been growing a long time. This reduces the cost of conservation to a large extent, making it cheaper to protect populations in their natural habitat.
- In-situ conservation offers a way to protect a large number of organisms simultaneously, known or unknown to science. It not only conserves a vast number of species of living organisms but also provides an opportunity to evolve.
- A natural ecosystem allows the free play of natural agencies like droughts, storms, snow, fluctuation in temperatures, excessive rains, fires, pathogens, etc., which provides an opportunity for the organisms to adjust to the prevailing conditions of the environment and evolve into a better adapted life form.
The disadvantages of in-situ conservation are:
- It requires large areas of Earth’s surface, which is often difficult in the face of growing demand for space.
- Protected areas are not always large enough and not well-maintained.
- Many protected areas like national parks, sanctuaries, etc., are often used for tourism or other such activities.
3. How do indiscriminate hunting and introduction of exotic species affect biodiversity?
Answer: Indiscriminate hunting and the introduction of exotic species significantly affect biodiversity by contributing to species extinction and threatening native populations.
According to a report mentioned, rhino poaching in and around Kaziranga National Park has increased, and 25 rhinos were poached in 1995. Asian elephants face extreme danger of extinction because of poaching and lack of check on trafficking in wild animals by the Government. The Wildlife Society of Orissa has reported that 57 elephants were shot dead by poachers for ivory between 1992-96. About 175 lions and 226 tigers died in Indian zoos as against 46 lions and 142 tigers in the protected areas between 1995 to 2000. The extinction of the Dodo bird of Mauritius and cheetah—the fastest mammal of India (the last one died in Delhi zoo in 1994)—occurred due to excessive hunting. The disappearance of tigers from Sariska National Park is a recent example of indiscriminate hunting and poaching. Furthermore, Musk deer (Moschus moschiferus) and great one-horned rhinoceros (Rhinoceros unicornis) in India are being indiscriminately killed for the medicinal value of their musks and horns respectively, which is a form of international trade driven by hunting.
Exotic species are known to adversely affect native species through factors like competition for food and space, predation, habitat destruction, transmission of disease, and parasites. Some known native species which are threatened due to the introduction of exotic species include:
(i) Eichhornia crassipes (water hyacinth) which has become a dominant species in pools and ponds.
(ii) Periplaneta americana (American cockroach) which is threatening the existence of the native oriental cockroach Blatta orientalis.
(iii) Goats and rabbits introduced in the Pacific and Indian Ocean areas which are destroying the habitats of several plants, birds, and reptiles.
(iv) Lantana camera, a plant, which could now enter into forests and seriously compete with natural species growing there.
These actions lead to a reduction in the number of native species, disrupt ecosystems, and ultimately diminish overall biodiversity.
4. Write a note on Habitat Conservation.
Answer: Habitat conservation, particularly conservation beyond Parks, Sanctuaries, and Reserves, acknowledges that it is in a way impossible to stop the expansion of human enterprise, reckless overexploitation of natural resources, and pollution of the environment within the time frame available to us. This will have a serious negative impact on society, as the number of species shall be reduced. Due to loss of germplasm or the gene pool, the genetic resources which now occur in the wild unknown to us shall disappear before we discover their utility.
If we have to conserve natural habitats, we shall have to:
(a) increase agricultural productivity and provide the people of the area with alternatives so that further encroachments on the natural habitats are checked.
(b) promote and intensify forest management and develop compensatory plantations.
(c) implement a vigorous forest conservation policy so that remaining natural habitats are protected from all types of exploitation.
(d) discourage developmental projects affecting wild land or natural habitats of wildlife adversely.
Some of the projects described for habitat conservation include:
(i) Increasing agricultural productivity: A high priority area in future is more intensive research and trial of new technology for sustainable agriculture on soils which are poor in nutrients and on which much of our biologically significant habitats occur. Introduction of land reforms, along with equitable distribution of land and sustainable agriculture could go a long way to remove the pressure of over-exploitation from forested wild land.
(ii) Intensifying forest productivity and reforestation: A better alternative for meeting the timber and fuelwood demand could be fast-growing species of woody plants which can be grown on degraded land. Timber and fuelwood are the two common commodities for which forests are usually ravaged and depleted. Support for agroforestry programmes reduces the pressure of demand on natural habitats.
Pursuing vigorous forest policy is crucial. Political awareness and mobilising support for conservation of natural habitats (forests) and wildlife will achieve hardly any results until the fundamental policy needed to ensure the conservation is well defined. The needs on a priority basis are:
(i) To achieve sustainable agriculture, a dedicated and strong political commitment to land reforms and redistribution policy adjacent to the threatened habitats should be taken.
(ii) Diversion of resources to the development of intensive agriculture in buffer zones around threatened forest land of the agricultural sector.
(iii) Imposing higher taxes on timber export which will in turn encourage curbing logging operations, fuelwood collection and providing alternatives by planting fast growing species on degraded landscapes.
(iv) Screening developmental projects affecting natural habitats and wildlife. Following types of economic development projects require close scrutiny and environmental impact assessment: (a) Agricultural and natural husbandry programmes, (b) Projects for transportation, (c) Hydroelectric projects, and (d) Industrial and mining projects. These projects affect natural habitats and wildlife directly or indirectly.
In-situ conservation of food plants and their wild varieties has been proposed. These can carry an enormous amount of genetic diversity distributed among numerous land areas. If farmers carry out traditional agriculture along with cultivation of high yielding modern varieties, much of the problems of in-situ conservation of crop plant germ plasm could be automatically solved. There is a need to integrate rural development with conservation efforts, possible if small farmers acquire sufficient economic stability and legitimate standards of living, requiring outside support and village-level development programmes.
Restoration of degraded habitats aims to enable the ecosystem to do things that cannot be done by degraded systems. For a meaningful change, the restoration of degraded habitats shall have to be linked with economic activity which provides for mankind. Creation of production-oriented ecosystem is development-linked conservation, a type of agriculture blended with ecology. By integrating nature’s restoration requirement with economic needs of people, the terrestrial fabric of our planet can be rebuilt.
5. How can people and wildlife conflicts be mitigated?
Answer: In the context of mitigating people and wildlife conflicts, it is noted that natural selection cannot be simulated in ex-situ populations, and for all practical purposes, ex-situ conservation leads to domestication and disappearance of wild life genes. Wildlife which is painstakingly bred is not exactly the same as it would have been if it were allowed to continue in nature. Wildlife suffers because animals in captivity may undergo genetic adaptation to their artificial environment and become useless for their natural habitats. Captivity makes them incapable of living in the wild environment to the extent that no amount of acclimatisation or training can rehabilitate them in wild conditions. Also, ex-situ conservation may represent only a limited portion of the gene-pool of the species, and there are possibilities that the entire population of endangered species may be wiped out in a single stroke of natural calamity or catastrophe such as war caused by man.
However, with all the human wildlife conflicts, ex-situ care of breeding populations can effectively serve as means to conserve unique and useful traits rather than the entire species as such. This suggests that one way to manage the consequences of such conflicts, particularly for endangered species, is through carefully managed ex-situ conservation programs focused on preserving specific genetic traits.
Think and Answer
How is in-situ conservation superior to ex-situ conservation?
Answer: In-situ conservation is considered superior to ex-situ conservation in several ways.
It is the best strategy for long-term protection of biodiversity. In-situ conservation is a cheap and convenient way of conserving biological diversity, as we play a supportive role only. Factors detrimental to the existence of the species concerned are eliminated, and the species is allowed to grow in its natural environment in which it has been growing a long time, which reduces the cost of conservation to a large extent. It is cheaper to protect populations in their natural habitat.
In-situ conservation offers a way to protect a large number of organisms simultaneously, known or unknown to science, and not only conserves a vast number of species of living organisms but also provides an opportunity to evolve. A natural ecosystem allows the free play of natural agencies like droughts, storms, snow, fluctuation in temperatures, excessive rains, fires, pathogens, etc., which provides an opportunity for the organisms to adjust to the prevailing conditions of the environment and evolve into a better adapted life form. In contrast, with ex-situ conservation, new life forms cannot evolve.
Furthermore, natural selection cannot be simulated in ex-situ populations, and for all practical purposes, ex-situ conservation leads to domestication and the disappearance of wild life genes. Wildlife which is painstakingly bred ex-situ is not exactly the same as it would have been if it were allowed to continue in nature. Animals in captivity may undergo genetic adaptation to their artificial environment and become useless for their natural habitats. Captivity can make them incapable of living in the wild environment to the extent that no amount of acclimatisation or training can rehabilitate them in the wild conditions. As compared with wild populations, ex-situ conservation may represent only a limited portion of the gene-pool of the species.
Additionally, with ex-situ conservation, it is not always possible to maintain favourable environmental conditions, and this technique is adopted only for a few species.
Project Work & Activity
In the class hold a discussion on the pros and cons of ex-situ and in-situ conservation.
Answer: Do it yourself. Here are the instructions:
- First, Understand What We’re Talking About:
- Make sure you clearly understand “in-situ conservation.” Think of it as protecting plants and animals right in their natural homes, like in national parks or sanctuaries.
- Then, get clear on “ex-situ conservation.” This is about protecting them away from their natural homes, for example, in places like zoos, botanical gardens, or seed banks.
- Get Ready to Talk About In-Situ Conservation (Protecting them ‘in’ their homes):
- List down all the good points (pros). For example, it’s usually a cheaper way to protect many different types of plants and animals at once, and they can continue to live and adapt naturally to their environment. It’s considered the best way for long-term protection.
- Also, think about the difficulties or bad points (cons). For instance, these natural areas need a lot of land, which can be hard to find. Sometimes, these protected places might not be big enough or well looked after, and human activities like tourism can sometimes cause problems.
- Get Ready to Talk About Ex-Situ Conservation (Protecting them ‘ex’ternally, or away from home):
- List down the good points (pros). For example, animals and plants can get special care, which might help them live longer and breed more successfully. Scientists can also use special techniques to help them, and sometimes, species bred this way can be put back into the wild.
- Now, think about the difficulties or bad points (cons). It can be hard to always provide the perfect conditions they need. Animals might get too used to human care and find it hard to survive if they go back to the wild. Also, this method usually helps only a few species at a time, and they don’t get to evolve naturally. There’s also a risk that if something bad happens (like a disease or disaster) at the facility, a whole group could be lost.
- How to Participate in the Class Discussion:
- Your teacher will help manage the discussion.
- When you speak, share your points clearly.
- Pay attention and listen to what your classmates are saying.
- It’s good to share your opinion, even if it’s different, but always be respectful.
- Try to give reasons for your points – why do you think something is an advantage or a disadvantage?
- You can also talk about which method might be better for different kinds of situations or species.
Extras
Questions and Answers
1. Which bird species of Mauritius became extinct due to excessive hunting?
Answer: The Dodo bird of Mauritius became extinct due to excessive hunting.
26. Discuss the methods proposed for in-situ conservation of wild varieties of crop plants and their potential impact.
Answer: For the in-situ conservation of food plants and their wild varieties, the proposal involves conserving indigenous varieties. These varieties can carry an enormous amount of genetic diversity distributed among numerous land areas.
A key method suggested is that if farmers carry out traditional agriculture alongside the cultivation of high-yielding modern varieties, much of the problems of in-situ conservation of crop plant germ plasm could be automatically solved.
Furthermore, there is a need to integrate rural development with conservation efforts. This integration is considered possible on a larger scale if small farmers acquire sufficient economic stability and legitimate standards of living. To achieve this, outside support, such as village-level development programmes, are required.
The potential impact of these methods is the preservation of a vast pool of genetic diversity found in wild crop varieties, which is crucial for future agricultural resilience and development. By solving the problems of crop plant germ plasm conservation in their natural settings, we can ensure these genetic resources are available for future use.
MCQs
1. Species extinction accelerated from one species per decade to what rate per year?
A. Dozens
B. Hundreds
C. Thousands
D. Millions
Answer: B. Hundreds
60. Which technology uses low-temperature storage of gametes and embryos?
A. Chemical immobilisation
B. Cryopreservation
C. Artificial insemination
D. Embryo transfer
Answer: B. Cryopreservation
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