Chapter 13: Biodiversity and Conservation Application Questions | biology Class 12 CBSE

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Chapter 13: Biodiversity and Conservation Application Questions | biology Class 12 CBSE | ByteNotes.in

Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 1

Applied Concept

A conservationist is tasked with protecting the maximum number of species with limited funding. Based on the concept of biodiversity hotspots, how should she prioritise her efforts? What percentage of land area do hotspots cover, and how much extinction can be prevented?

She should focus on the 34 identified biodiversity hotspots, which are regions combining exceptionally high species richness, high endemism and accelerated habitat loss — giving the greatest conservation return per unit of land protected.
Although all 34 hotspots together cover less than 2 per cent of Earth's total land area, strict protection of these areas could reduce ongoing mass extinctions by almost 30 per cent, making them extraordinarily efficient targets for conservation investment.
In India specifically, the three hotspots — Western Ghats and Sri Lanka, Indo-Burma and Himalaya — should receive highest priority since they harbour species found nowhere else on Earth; losing these areas would mean irreplaceable global biodiversity loss.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 2

Applied Concept

A farmer notices that his orchard's fruit yield has drastically reduced, even though the plants are healthy. An ecologist visiting the farm identifies a significant decline in bee populations in the area due to pesticide use. Relate this observation to the 'broadly utilitarian argument' for biodiversity conservation.

The farmer's problem is a direct consequence of reduced pollination services — an ecosystem service provided by biodiversity. Bees and other pollinators are part of the broadly utilitarian argument that biodiversity performs critical functions sustaining human livelihoods.
The broadly utilitarian argument holds that biodiversity plays a major role in ecosystem services; pollination by bees, bumblebees, birds and bats enables plants to produce fruits and seeds. Without pollinators, plants cannot set fruit, explaining the yield decline despite healthy plants.
This scenario illustrates that biodiversity loss — even of a single functional group like pollinators — has direct economic and practical consequences, and that the value of biodiversity cannot be understood only in terms of direct products; its service functions are equally or more critical for human well-being.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 3

Applied Concept

With reference to the Nile perch introduced into Lake Victoria and the African catfish introduced into Indian rivers, explain how alien species invasions threaten native biodiversity.

Alien species invasions occur when non-native species introduced unintentionally or deliberately become invasive and drive indigenous species to decline or extinction; the Nile perch deliberately introduced into Lake Victoria in East Africa eventually led to the extinction of more than 200 species of ecologically unique cichlid fish.
In India, the African catfish Clarias gariepinus was illegally introduced for aquaculture purposes; as a predatory alien species, it poses a serious threat to indigenous catfishes in Indian rivers, potentially disrupting aquatic food webs and eliminating native species that evolved in these systems over millions of years.
Both cases demonstrate that alien species can be more damaging than habitat loss in certain contexts — by outcompeting, predating or transmitting diseases to native species with no evolutionary defence. Prevention of alien species introduction is far cheaper and more effective than attempting to control or eradicate them once established.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 4

Applied Concept

A botanist studying the Khasi Hills of Meghalaya finds an unusually high density of rare plant species in a small forest patch that is not a formally designated protected area. Locals explain that the forest is sacred. Explain this phenomenon in the context of biodiversity conservation.

The forest is a sacred grove — a tract of forest set aside and venerated by local communities based on religious and cultural traditions, where all trees and wildlife are given total protection. This represents a culturally embedded form of in situ conservation predating formal legal systems.
In Meghalaya, sacred groves in the Khasi and Jaintia Hills are specifically documented as the last refuges for a large number of rare and threatened plants — exactly matching the botanist's observation. Cultural and spiritual reverence has effectively protected these patches from exploitation.
This case illustrates that indigenous and cultural conservation practices can be highly effective, often protecting biodiversity in areas where formal government mechanisms do not reach. Integrating sacred grove protection into national conservation policy can significantly strengthen India's in situ conservation network at minimal cost.

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Application Question

Hard difficulty • Concept in a practical situation

Hard

Question 5

Applied Concept

A wildlife biologist notices that a large forested area has been divided into four smaller patches by a new highway and two agricultural zones. Predict the ecological consequences for animal populations using the concepts of habitat fragmentation and species-area relationships.

According to the species-area relationship (log S = log C + Z log A), smaller areas support fewer species; breaking one large forest into four smaller patches effectively reduces the available area for each species, leading to a decline in species richness in each patch compared to the original whole habitat.
Habitat fragmentation particularly affects large mammals and wide-ranging birds that require large territories to meet their foraging, breeding and social needs; isolation of patches prevents movement between them, reducing gene flow and increasing inbreeding in small isolated populations.
Migratory animals that depend on corridors connecting habitats across seasons will be severely disrupted by the highway barrier, potentially preventing access to critical breeding or feeding grounds and causing local population extinctions even though the habitat patches themselves still exist.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 6

Applied Concept

A pharmaceutical company proposes to explore the tropical rainforests of the Western Ghats for potential medicinal compounds. Relate this to the concept of bioprospecting and the narrowly utilitarian argument for biodiversity conservation.

Bioprospecting involves exploring molecular, genetic and species-level diversity for products of economic importance; the pharmaceutical company's proposal is a classic bioprospecting initiative in one of India's biodiversity hotspots — the Western Ghats — which harbours high species richness and endemism.
The narrowly utilitarian argument for conservation holds that biodiversity provides direct economic benefits including products of medicinal importance; more than 25 per cent of drugs currently sold worldwide are plant-derived, and 25,000 plant species contribute to traditional medicines globally, demonstrating that unexplored tropical plants hold enormous medicinal potential.
This application also highlights the critical reason for conserving tropical rainforest biodiversity before it is lost — species that become extinct before being discovered and screened represent irreplaceable lost potential for pharmaceutical discovery, reinforcing the economic case for urgent and comprehensive in situ conservation of the Western Ghats.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 7

Applied Concept

A specific butterfly species becomes extinct in a forest ecosystem due to habitat destruction. Soon after, several wild orchid species in the same forest also begin to disappear. Explain the likely relationship between these two events using the concept of co-extinction.

Co-extinction occurs when a species becomes extinct and other species dependent on it in an obligatory way also become extinct; in a coevolved plant-pollinator mutualism, extinction of the pollinator (the butterfly) inevitably leads to extinction of the plant species (the orchid) it exclusively pollinates.
Wild orchids that depend entirely on specific butterfly species for pollination cannot reproduce in the absence of their pollinators — no fruit or seed is produced, and the plant population progressively declines to extinction even if the habitat remains otherwise intact.
This cascade illustrates that biodiversity loss has multiplier effects beyond the immediate extinction event — the 'sixth extinction' is far deadlier than raw extinction numbers suggest because each primary extinction triggers secondary co-extinctions in networks of obligatory ecological relationships.

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Application Question

Hard difficulty • Concept in a practical situation

Hard

Question 8

Applied Concept

With reference to the Amazonian rainforest, discuss why its conservation is a matter of global concern and not just a national issue for Brazil.

The Amazon rainforest is estimated to produce, through photosynthesis, 20 per cent of the total oxygen in Earth's atmosphere — a service that benefits all life on Earth, not just Brazil. Its destruction would significantly alter atmospheric composition globally.
The Amazon is home to the greatest biodiversity on Earth — over 40,000 plant species, 3,000 fish, 1,300 birds, 427 mammals and 427 amphibians — much of it endemic and found nowhere else. Loss of this biodiversity would be an irreversible global tragedy affecting pharmaceutical, agricultural and ecological resources worldwide.
The Convention on Biological Diversity (1992 Earth Summit) explicitly recognises that biodiversity knows no political boundaries and its conservation is a collective responsibility of all nations, establishing the principle that globally significant ecosystems like the Amazon require international cooperation, financing and oversight, not just national management.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 9

Applied Concept

A seed bank is being established to preserve the genetic diversity of crop plants in India. Justify the scientific rationale for this ex situ conservation measure, connecting it to genetic diversity concepts from the chapter.

India possesses enormous genetic diversity in crop plants — over 50,000 genetically different strains of rice and 1,000 varieties of mango; seed banks preserve this genetic diversity as physical samples of seeds that can be maintained for long periods under controlled low-temperature and low-humidity conditions.
Genetic diversity within a species determines its ability to adapt to new environmental conditions, resist novel diseases and respond to breeding programmes; the 50,000 rice strains represent different genetic combinations that may carry resistance genes, drought tolerance or nutritional traits not yet exploited but potentially crucial for future food security.
As agricultural systems increasingly rely on a few high-yielding varieties, wild and traditional genetic diversity is being lost from farmers' fields; seed banks are therefore the primary ex situ safety net ensuring that this genetic heritage is not permanently lost before its potential value is understood or needed.

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Application Question

Medium difficulty • Concept in a practical situation

Medium

Question 10

Applied Concept

A field ecologist studying two forest plots — one in Ecuador and one in the American Midwest — finds that the tropical plot has up to 10 times more vascular plant species than the temperate plot of equal area. Using the three hypotheses for tropical species richness, explain this observation.

The speciation-time hypothesis explains that Ecuador's tropical latitude has remained climatically undisturbed for millions of years — unlike the Midwest, which experienced repeated glaciations — providing far longer evolutionary time for plant species to diversify and accumulate, resulting in higher richness.
The environmental constancy hypothesis argues that Ecuador's tropical environment is less seasonal and more predictable than the seasonal temperate Midwest, allowing plants to specialise into narrower niches without seasonal generalism, thus packing more species into the same area through niche differentiation.
The productivity hypothesis explains that the tropics receive more solar energy, driving higher primary productivity in the Ecuadorian forest; this greater energy availability supports a more complex ecosystem with more species at all trophic levels, indirectly sustaining the 10-fold difference in vascular plant species observed.

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Chapter 13: Biodiversity and Conservation | Application Questions

A conservationist is tasked with protecting the maximum number of species with limited funding. Based on the concept of biodiversity hotspots, how should she prioritise her efforts? What percentage of land area do hotspots cover, and how much extinction can be prevented?

With reference to the Nile perch introduced into Lake Victoria and the African catfish introduced into Indian rivers, explain how alien species invasions threaten native biodiversity.

A botanist studying the Khasi Hills of Meghalaya finds an unusually high density of rare plant species in a small forest patch that is not a formally designated protected area. Locals explain that the forest is sacred. Explain this phenomenon in the context of biodiversity conservation.

A wildlife biologist notices that a large forested area has been divided into four smaller patches by a new highway and two agricultural zones. Predict the ecological consequences for animal populations using the concepts of habitat fragmentation and species-area relationships.

A pharmaceutical company proposes to explore the tropical rainforests of the Western Ghats for potential medicinal compounds. Relate this to the concept of bioprospecting and the narrowly utilitarian argument for biodiversity conservation.

A specific butterfly species becomes extinct in a forest ecosystem due to habitat destruction. Soon after, several wild orchid species in the same forest also begin to disappear. Explain the likely relationship between these two events using the concept of co-extinction.

With reference to the Amazonian rainforest, discuss why its conservation is a matter of global concern and not just a national issue for Brazil.

A seed bank is being established to preserve the genetic diversity of crop plants in India. Justify the scientific rationale for this ex situ conservation measure, connecting it to genetic diversity concepts from the chapter.

A field ecologist studying two forest plots — one in Ecuador and one in the American Midwest — finds that the tropical plot has up to 10 times more vascular plant species than the temperate plot of equal area. Using the three hypotheses for tropical species richness, explain this observation.

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