Important Questions Class 12 Biology Chapter 15

Chapter 15 – Biodiversity and Conservation

Important Questions for CBSE Class 12 Biology Chapter 15 – Biodiversity and Conservation 

Chapter 15 Biology Class 12 Important Questions cover our biosphere exhibiting enormous diversity at all levels of biological structure, from macromolecules to biomes, not just at the level of species.

With these Biology Class 12 Chapter 15 Important Questions, students will come to know that Edward Wilson used the term “biodiversity” to refer to the whole of diversity at all levels. The three that matter most are ecological diversity, species diversity, and genetic diversity. The survival of humanity depends on the planet’s biodiversity, and its preservation is urgently required.

Moreover, with these Class 12 Biology Chapter 15 Important Questions, Extramarks will provide students with detailed and authentic solutions to important questions. 

CBSE Class 12 Biology Chapter 15 Important Questions

Study Important Questions for Class 12 Biology Chapter 15 – Biodiversity and Conversation

1. Name an ecosystem which is severely damaged by habitat loss and fragmentation.

Ans. The tropical rainforest has been severely damaged by habitat loss and fragmentation.

2. When we move from the poles to the equator, what trend is observed concerning species diversity?

Ans. Species diversity generally decreases while going from the equator to the poles.

3. Name the region with the highest biodiversity on the earth. What is the name of the forest in the region?

Ans. Amazonian rain forests, also known as the Lungs of the Planet, are the region which has the highest biodiversity on earth.

4. As per ecologists, the value of Z will be in the range of 0.1 to 0.2 irrespective of the taxonomic group. In a species-area relationship, when will the slope be steeper?

Ans. The slope of the line will be steeper when the species-area relationship is analysed in a very large area like an entire continent.

5. Explain cryopreservation. What purpose is it used for?

Ans. Cryopreservation is storing  any material in liquid nitrogen at 196 degrees Celsius. It is useful in conserving biodiversity as it can be done to preserve species in fertile conditions for a longer period.

6. Why is genetic variation shown by the medicinal plant Rauwolfia vomitoria? 

Ans. Genetic variation is shown in the medicinal plant Rauwolfia vomitoria because the greater the genetic variation, the more variety of Reserpine (active chemical) can be used for a host of different purposes.

7. What is the full form of IUCN?

Ans. IUCN is the International Union of Conservation of Nature and Natural Resources.

8. What is the full form of MAB?

Ans. MAB stands for Man and Biosphere program.

9. Describe hot spots.

Ans. Hot spots are the main focus area for conservation that are highly rich in species with high endemism and are under threat of extinction.

10. Which are the threatened animal species in India?

Ans. The Great Indian Rhinoceros and Swamp Deer are threatened animal species in India.

11. Write some of the features that make a community stable. 

Ans. A community is stable if it has the qualities listed below.

• Ability to withstand infrequent perturbations
• Productivity varies less from year to year
• Defending against alien species incursions

12. What is the difference between endemic and exotic species? 

Ans. Exotic species are native species that are only found in a certain geographic area, whereas endemic species are those that have spread into a region from another region.

13. What is bioprospecting and endemism? 

Ans. Bioprospecting is the exploration of new products that are developed and brought to market using biological resources.

Endemism describes species that are restricted to a single geographic area. They cannot be found anywhere.

14. What role does genetic diversity play in the rauwolfia vomitoria plant?

Ans. Reserpine, a tranquiliser medication, is derived from this plant. The concentration and effectiveness of the reserpine produced by the plant might vary genetically.

15. Which of the following, in your opinion, accounts for the majority of biodiversity loss among the four primary factors, which are, over-exploitation, habitat loss and fragmentation, alien species invasion and co-extinction? Justify your answer.

Ans. Fragmentation and habitat loss. Because it results from the removal and over-exploitation of forest areas for urban and industrial development. Overpopulation has depleted natural resources and devastated forests. When larger ecosystems are divided up into smaller pieces, birds and mammals migrate in search of a larger territory, which leads to population decline.

16. Why do subtropical and tropical regions have more biodiversity than temperate ones?

Ans. It is because there are fewer weather fluctuations in these areas, which prevents disturbance. Consequently, the species’ evolutionary time for diversity was long. Less species variety occurs in temperate regions because of the environment’s greater seasonality and unpredictability.

17. Can a natural community maintain its diversity and output for more than a century?

Ans. No, it is not feasible since natural habitats are never preserved in the real world, resources cannot always remain abundant, and environmental circumstances for survival are constantly changing.

18. Describe sacred groves. What part do they play in biodiversity preservation?

Ans. They are sacred texts that are extremely important to the local populations. They are protected by local communities through taboos and social traditions that encompass ecological and spiritual values and are devoted to ancestors’ spirits and regional deities. They can be found in places like the Aravalli Hills, Meghalaya, the Western Ghats, etc., and are rich in biodiversity, fostering unique plant and animal species.

19. Describe two ways in which biodiversity benefits people? 

Ans. We gain economic advantages from a variety of entities, including

• fibre, food, and firewood
• industrial goods and building supplies
• pharmaceuticals made from plants
• natural pollinators, pure oxygen, and flood and soil erosion prevention
• microorganisms’ recycling of waste
• nutrient replenishment

20. Is solar energy more accessible in tropical regions? Explain your response.

Ans. Yes, solar energy is more accessible in tropical regions. This is because:

• Less atmosphere must be traversed for the sun’s rays to travel, which results in less energy being wasted through reflection and absorption by the atmosphere.
• The sun’s rays are stronger and more focused.
• In tropical rainforests, where dense vegetation is present, radiation absorption increases.

21. In 2004, IUCN listed how many species of animals and plants? How much global species diversity did Robert May describe?

Ans. In 2004, IUCN listed over 1.5 million species of plants and animals. Robert May described 7 million global species.

22. Define co-extinction with an example.

Ans. The disappearance of the species with the extinction of any other species of plants and animals with which it was linked in an obligatory way is referred to as co-extinction. One example is plant-pollinator mutualism.

23. Explain the IUCN red list. Name two uses of this list.

Ans. The International Union of Conservation of Nature and Natural Resources has a red data list which is the data of taxa facing the risk of extinction. The primary uses of this list are as follows.

(i) Red data list helps identify the species with a high risk of extinction.

(ii) Red data list helps provide awareness of the threat to biodiversity.

24. Why is the species diversity of plants much lesser than that of animals?

Ans. The species diversity of plants is much lesser than that of animals because, unlike plants, many animals have a nervous system which controls and coordinates some activities of other animals. Animals also possess receptors which help in receiving environmental stimuli, and some of these responses are acceptable and ensure the survival of organisms in changing environmental conditions.

25. It is said that the Amazon Rainforest in South America has the greatest biodiversity in the world. Justify.

Ans. The greatest biodiversity on earth is found in the Amazonian rainforest, which is in South America. This rainforest is the birthplace of around 40000 species of plants, 125000 species of insects, 3000 species of fishes, 378 reptiles, 1300 birds, and many more.

26. What do you understand about lay species diversity? Name any two measures of species diversity.

Ans. Lay species diversity refers to various types of species present in a region. Two measures of species diversity are as follows.

(i) Species evenness: Species evenness refers to the relative abundance in which the species represent their presence in an area.

(ii) Species richness: Species richness is referred to the number of species found per unit area.

27. Explain sacred groves. What is the role of sacred groves in conservation?

Ans. Sacred groves are described as sacred forest patches which are around temples. Tribal people are mostly prohibited to cut even a single branch of a tree in these sacred groves. Thus, many endemic species flourish in this region.

28. Describe IPR. Mention the disadvantages of IPR.

Ans. IPR stands for Intellectual Property Rights. In some cases, IPR is used to patent the transformed plants, animals, and microorganisms due to which they become special private property.

Some of the disadvantages of Intellectual Property Rights are as follows.

(i) The price of seeds increases due to the application of IPR.

(ii) Local varieties are replaced with exotic varieties.

(iii) The diffusion of new varieties is slow.

(iv) In agriculture, the MNC companies have higher domination.

29. Why is it difficult to evaluate global diversity for prokaryotes?

Ans. It isn’t easy to evaluate global diversity for prokaryotes because of some of the reasons mentioned below.

(i) In laboratory conditions, many of the global diversity species cannot be cultured.

(ii) The conventional taxonomic method is not preferable for identifying microbial species.

(iii) The global diversity of species would be put into huge numbers with the new biochemical and molecular biology techniques.

30. Why do the tropics account for greater biological diversity? Give reasons.

Ans. The reasons that tropics may account for greater biological diversity are as follows.

(i) In the tropical region, more solar energy is available, and it contributes to high productivity, which leads to greater biological diversity.

(ii) The environment in tropical areas is less seasonal, and it can also be predicted.

(iii) Tropical latitude is relatively undistributed for millions of years. Thus, they have greater biological diversity.

31. What is the necessity of conserving biodiversity?

Ans. There are many reasons for conserving biodiversity. Some of them are mentioned below.

(i) Narrow utilitarian: The economic benefits for human beings include food, fibre, medicinal products, industrial products, etc.

(ii) Broad utilitarian: Biodiversity plays an important role in ecosystem services such as oxygen production, pollination of flowers, and pleasure in nature like bird watching or watching the flowers spring.

32. Describe the importance of biodiversity to human beings.

Ans. Biodiversity is very important for human beings in many ways. Some of the ways have been discussed below.

(i) Food and other varieties: Biodiversity directly or indirectly gets added as a source of food, shelter, and cloth for human beings.

(ii) Resins: The sticky part of plants is a resin used by humans in different ways.

(iii) Oils: Different kinds of oils are made out of plants.

(iv) Medicines: Biodiversity plays an important role in medicines and drugs. Living organisms also contain therapeutically useful substances.

(v) Ecosystem stability: The food web or food chain flows in different trophic levels, and the biochemical cycle happens naturally with the biodiversity.

(vi) Nature: People in India grow plants as they consider them sacred and recreational.

33. Describe the biodiversity situation in India.

Ans. India is ranked as the 10th mega biodiversity in the world. This is because of the different varieties of climatic conditions in different ecological habitats. The biodiversity of India involves 47000 plants and 81000 species of animals. A huge number of species in India are native. India has 166 crop plants and 320 cultivated wild relatives. In marine biodiversity, India is considered to be highly rich. The two hotspots in India are the Western Ghats and the Eastern Himalayas.

34. An alien hydrophyte called Eichhornia crassipes was introduced to India. Mention the issue this plant poses.

Due to its rapid clogging of stagnant water bodies, the water hyacinth (Eichhornia) introduced to India is endangering native species of aquatic life in ponds, lakes, etc.

35. How is the invasion of alien species regarded as one of the causes of the decline in biodiversity? Support your response with an example.

Indigenous species are driven to extinction as a result of invasion by alien species, which also threaten native species.

More than 200 species of cichlid fish in Lake Victoria went extinct as a result of the introduction of Nile perch.

Introduced plants like Lantana and carrot grass (Parthenium) have become invasive and harmed the ecology. They endanger the native plant species that live in our forests.

36. Give a specific illustration to support your claim that mutualistic environments 

• are one of the main contributors to the loss of biodiversity. 

• have the propensity to coevolve.

Ans. Mutualists frequently co-evolve in nature, such as the Mediterranean orchid named Ophrys. To get a particular kind of bee to pollinate it, Ophrys uses sexual deception. A flower’s petal resembles a female bee. Unless the orchid flower coevolves to maintain its likeness to the female bee, pollination success will be lowered if the female bee’s colour pattern slightly changes.

Coextinction is a member of the Evil Quartet in which an organism having a necessary relationship, such as a mutualistic link between plant pollinators, will go extinct if the other partner does so in the natural world.

37. There are more than a thousand different mango varieties in India. What type of biodiversity does this represent and what makes it possible?

Ans. In India, the various mango cultivars show the genetic variety of the country.

India is located in a tropical region, where the climate is stable and predictable, thus the area area exhibits great biodiversity. Additionally, there is more sun energy accessible, which increases production.

38. What are the major causes of the loss of biodiversity?

Ans. The main reasons for the loss of biodiversity are as follows.

(i) Habitat loss: Habitat loss and fragmentation of crops or converting that into grassland raise beef cattle. The total loss of habitat takes away many plants and animals from their home, and they face extinction.

(ii) Overexploitation: The species become extinct when nature is over-exploited by human beings for any natural resources.

(iii) Invasion of alien species: The alien species become invasive and fight with native species, which is the cause of the extinction of indigenous species.

(iv) Co-extinction: Co-extinction is when a species becomes extinct, and the plants or species related to the extinct species also become extinct.

39. Mention any two approaches for ex-situ conservation and in-situ conservation as a plan of action for biodiversity conservation.

Ans. Considering the strategy for biodiversity conservation, the two approaches for ex-situ and in-situ conservation are as follows.

Ex- situ conservation:

(i) Seed bank

(ii) Crypto Preservation

(iii) Creation of natural parks and wildlife sanctuaries.

In-situ conservation:

(i) Sacred groves

(ii) Legal protection in rich areas which are ecologically rich

(iii) National parks and sanctuaries.

40. Describe how the entrance of an alien species affects the local species diversity.

Some alien species resort to invasion when they unintentionally or intentionally familiarise a particular habitat, which results in the decline or extinction of native species. For example, lantana and water hyacinth have become invasive, while the invasion of Lake Victoria in East Africa by the giant predator fish Nile perch resulted in the demise of more than 200 species of ecologically distinct cichlid fish. Due to a scarcity of food, both the predatory Nile perch and the cichlid fish went extinct.

41. How can we prevent the loss of biodiversity? 

Ans. Biodiversity is the presence of various habitat types, species, ecosystems, gene pools, and genes in a specific location. With the right conservation tactics and biotic and abiotic resource management, it can be preserved. The following are a few conservation tactics.

• Native plant and animal species should be preserved or protected in their natural environments.
• Preserving vital habitats, such as sites for breeding and feeding, and promoting the expansion and reproduction of endangered species
• Regulation of hunting or its outright prohibition
• It is important to protect migratory species’ habitats through bilateral and international agreements.
• Educating people about the relevance of biodiversity conservation
• Preventing the overuse of natural resources

42. Can you come up with a scientific justification for the direct link between ecological stability and diversity other than the relationship Paul Ehrlich cited?

Ans. Imagine a situation where a variety of species are developing and plants support a variety of species on which a collection of insect species depends for their nutritional needs. When this particular plant species dies, the dependent insect species suffer greatly because there is no food available. Furthermore, if the plant was a nitrogen fixer, its demise would suggest that nitrogen was not used to replenish the soil’s nutrients. The plant’s ability to grow would likewise be impacted by this. If this is done and happens frequently, it would have a detrimental effect on the entire ecosystem. From the justification given above, it can be concluded that there is a direct link between ecological stability and diversity.

43. Why does species variety decrease as we move farther from the equator?

Ans. It is because the environmental condition gets worse as the temperature drops. The volume and intensity of solar radiation decrease and the amount of vegetation likewise declines. Fewer resources are available to support the assortment of species. As we get closer to the poles, biodiversity declines because harsh conditions make it impossible for species to adapt and survive.

44. Make notes on Paul Ehrlich’s “rivet popper theory”.

Ans. Paul Ehrlich put forth a theory to explain the benefits of species richness, arriving at it by contrasting each species with a rivet found in an aeroplane’s body. It illustrates how the species act as the rivets that hold the ecosystem together like the pieces of an aeroplane. The safety of the trip would initially be unaffected if every passenger started bringing rivets home (representing species extinction), but gradually the plane would become unstable and crash, signifying that species would become threatened and then extinct.

45. What is meant by the invasion of an alien species? List two foreign species of plant and animal that are a threat to indigenous Indian species. 

Ans. Alien species invasion refers to the intentional or accidental introduction of exotic species by humans into new islands or nations.

For instance, the introduction of Nile perch to Lake Victoria in East Africa resulted in the loss of over 200 species of cichlid fish. Threats to our native species in India have come from alien plant species like Lantana camara and alien animal species like Clarias gariepinus.

46. Where would you anticipate a higher species diversity, in the tropics or in the polar regions? Give justifications for your answer.

Ans. Tropical latitudes have higher levels of biodiversity than temperate or polar locations. Some of the reasons are as follows.

• The passage of time affects speciation. The tropics have stayed unaffected and have had more time to evolve species diversity than the temperate areas, which were subjected to periodic glaciers in the past.
• Tropical regions have greater access to solar radiation. This increases productivity that directly and indirectly increases species diversity.
• The tropics’ climate is less cyclical, comparatively more stable, and predictable, which promotes species diversity and niche specialisation.

These Important Questions are references to CBSE extra questions, CBSE revision notes, and CBSE sample papers from the CBSE syllabus. To secure good marks, students can also refer to CBSE’s past year’s question papers provided by Extramarks.