Unit 3 - Practice Quiz

Biodiversity, or biological diversity, refers to the total variety of life on our planet, encompassing the diversity within species (genetic), between species (species), and of ecosystems.

Genetic diversity is the variety of genes within a single species. It is the reason individuals within a species show different traits.

Species diversity refers to the variety of different species (plants, animals, fungi, and microorganisms) present in a given area.

Ecosystem diversity deals with the variety of ecosystems or habitats existing in a geographical region, like forests, deserts, grasslands, and aquatic ecosystems.

Ecosystem services are the benefits that humans receive from ecosystems. Pollination by insects like bees is a critical service for agriculture and food production.

The economic value of biodiversity includes all the commercial products and resources that humans harvest from nature, such as food, timber, fuel, and raw materials for medicines.

The aesthetic value of biodiversity relates to the beauty and pleasure people derive from observing and experiencing nature, which forms the basis for recreation and tourism.

To qualify as a biodiversity hotspot, a region must have a high percentage of endemic plant life (species found nowhere else) and be under significant threat of habitat loss.

The Western Ghats, along with Sri Lanka, is recognized globally as one of the most significant biodiversity hotspots due to its rich and unique flora and fauna.

The destruction, degradation, and fragmentation of natural habitats due to human activities like deforestation and urbanization is the leading cause of species extinction worldwide.

Poaching refers specifically to the illegal hunting, capturing, or killing of wildlife, often for valuable parts like tusks, horns, or skins, and is a major threat to many species.

Invasive alien species are plants or animals introduced to a new environment where they lack natural predators and competitors, allowing them to spread rapidly and harm native biodiversity.

Extinction is the complete disappearance of a species from the planet when the last individual of that species has died.

The 'Endangered' (EN) category on the IUCN Red List is assigned to species that are facing a very high risk of becoming extinct in their natural habitat.

In-situ ('on-site') conservation involves protecting species in their natural environment, such as in national parks, wildlife sanctuaries, and biosphere reserves.

Ex-situ ('off-site') conservation involves protecting species outside their natural habitats. Seed banks, botanical gardens, and zoos are common examples.

A National Park is a protected area where ecosystems and their species are conserved within their natural surroundings, making it a prime example of in-situ conservation.

Rare species are those with small, often geographically localized, populations. While not immediately endangered or vulnerable, their small numbers make them susceptible to threats.

India is divided into several biogeographic zones. The Desert Zone covers the hot and dry regions of the country, primarily the Thar Desert in Rajasthan and parts of Gujarat.

A mega-diversity nation is one that harbors a high number of the Earth's species and has a significant percentage of endemic species (species found nowhere else). India meets these criteria.

This scenario illustrates the risk of genetic uniformity (low genetic diversity) within a species. The lack of varied genes for disease resistance in the wheat population made the entire crop vulnerable to a single pathogen. Higher genetic diversity would have increased the chances of some plants surviving.

Regulating services are the benefits obtained from the regulation of ecosystem processes. In this case, the mangroves are regulating a natural hazard (storm surge), which is a key example of this service category, distinct from providing a direct product (provisioning) or a non-material benefit (cultural).

The definition of a biodiversity hotspot is precise. It combines high irreplaceability (measured by endemic plants) with high vulnerability (measured by habitat loss), focusing conservation efforts where they are most needed.

This is a classic example of an invasive species causing extinctions through predation. The native cichlids had not evolved defenses against a large predator like the Nile Perch, which quickly decimated their populations.

The IUCN categories are based on quantitative thresholds. A population reduction of >70% falls under the criteria for 'Endangered' (EN), but a reduction of >80% (or an extremely small population size) is required for 'Critically Endangered' (CR). A reduction >50% is EN, and >30% is VU. Among the choices, CR represents the highest risk category reflecting such a drastic decline.

The key benefit of in-situ conservation is the preservation of not just the species, but its entire ecological and evolutionary context. This allows for ongoing adaptation to environmental changes, a process that is halted in the artificial setting of ex-situ conservation.

While the Gangetic plain is a large zone, the specific habitat of the one-horned rhino, the 'Terai' grasslands and Brahmaputra valley floodplains (like in Kaziranga and Manas), are part of this broader biogeographic zone, distinct from the other options.

India's immense biodiversity is a direct result of its wide range of ecosystems (from hot deserts to cold mountains, rainforests to coasts) and its unique geographical position, which has allowed species from different realms to migrate, mix, and evolve, leading to high species richness and endemism.

The edge effect is a direct consequence of habitat fragmentation. It describes the altered environmental conditions at the boundary of habitats, which can reduce the effective size of the habitat for species adapted to the stable conditions of the core interior.

An evolutionarily distinct species represents a unique branch of the evolutionary tree. Its extinction would mean the loss of millions of years of unique evolutionary history, a greater loss than that of a species with many close relatives.

Ex-situ conservation involves maintaining biological diversity outside of the natural habitat. A seed bank is a prime example, as it stores genetic material away from the original ecosystem. The other options are all forms of in-situ conservation, protecting species within their natural environments.

While these are different ecosystems (ecosystem diversity), the most striking and commonly cited difference between a tropical rainforest and a polar region is the vast number of different species (high species richness) in the former versus the very few species in the latter. This highlights the concept of species diversity on a large scale.

Bioprospecting utilizes the genetic and chemical information stored in living organisms (informational value) to develop products like medicines and industrial chemicals, which in turn have significant economic value. It's a direct application of biodiversity's informational potential for economic gain.

This is an innovative, eco-friendly solution that uses the elephants' natural aversion to bees. It addresses the conflict by creating a deterrent that elephants perceive as a threat, preventing them from entering fields. It is proactive and less intrusive than physical barriers or culling.

The dramatic and complex topography of the Himalayas creates numerous isolated valleys and microclimates. This geographical isolation has allowed populations of plants and animals to evolve independently, leading to the formation of many unique, endemic species.

The Indian Desert zone is not just the sandy Thar Desert but also includes the Rann of Kutch in Gujarat, which is a unique saline desert and seasonal salt marsh. This zone is characterized by its aridity and specialized, adapted fauna like the wild ass.

This is a perfect example of how the two strategies work together. The species was maintained and bred in a controlled environment (ex-situ) to increase its numbers, and then released back into its protected natural habitat (in-situ) to re-establish a wild population.

Poaching is the illegal hunting or capturing of wild animals. When this is driven by high demand for a specific product (like scales), it leads to over-exploitation, where the species is removed from the wild faster than it can reproduce, driving it towards extinction.

Rare species are those with small global populations that are not currently 'Endangered' or 'Vulnerable' but are at risk due to their restricted geographical range or low numbers. Their localized nature makes them susceptible to catastrophic events in their small habitat.

Ecosystem diversity refers to the variety of ecosystems in a given place. The question lists different types of large-scale interacting systems of organisms and their physical environment (deserts, rainforests, etc.), which is the definition of ecosystem diversity.

Beta diversity measures the turnover or change in species composition between habitats. A low percentage of shared species (5%) between Site A and Site C implies a very high turnover, hence the highest beta diversity. This reflects the strong ecological differences between a pristine primary forest and a human-modified plantation. A low beta diversity (as between A and B, with 50% shared species) indicates similar species composition, not that it is determined by gamma diversity.

The EDGE score is a combination of Evolutionary Distinctiveness (ED) and Global Endangerment (GE). Species B has the highest ED as it is the last member of an ancient family (80 mya divergence), representing a huge amount of unique evolutionary history. Even though its IUCN status is 'Vulnerable' (lower threat than EN or CR), its exceptionally high ED would likely give it the highest EDGE score, making it a top priority to prevent the loss of an entire major branch of the tree of life.

This is a key critique. Hotspots are 'hot' in terms of species diversity and threat but can be 'cold' in terms of total biomass or specific ecosystem functions. Focusing only on them risks ignoring large, functional ecosystems ('coldspots') like the Amazon or Congo basins (before they reach the threat threshold) or the taiga, which are crucial for global climate regulation and other services, despite having lower species density or endemism compared to a place like the Andes.

"Extinction debt" refers to the future extinction of species due to past events. Even though the species are still present, their populations may no longer be viable in the long run due to the fragmentation. The full impact is not immediate. The initial low decline is misleading; a significant number of extinctions are "locked in" and will occur over subsequent decades or centuries unless connectivity is restored.

This scenario highlights complex ecological interdependencies. A purely in-situ approach is likely to fail as the entire habitat is collapsing. A purely ex-situ approach severs the critical co-evolved relationships, making future reintroduction almost impossible. The integrated approach is the only one that conserves all three components of the ecological triad (plant, pollinator, fungus) and plans for assisted migration to a new, viable location, addressing the root threat of climate change.

The key to the Western Ghats' unique biodiversity, especially its high level of endemism, is its geological history and complex terrain. As part of the Indian plate that broke from Gondwanaland, it carried ancient lineages. Its long isolation allowed these lineages to radiate. Furthermore, the rugged mountains with deep valleys acted as 'refugia' during past arid periods, allowing species to persist in moist pockets and diverge, leading to high point endemism.

This question requires precise differentiation. Provisioning services are direct products (fish, timber). Regulating services are benefits from ecosystem processes (storm protection, water purification). Supporting services are necessary for all other services (the nursery habitat that supports the fish population). Option B correctly classifies each service, notably distinguishing between the fish (provisioning) and the nursery habitat that allows them to exist (supporting).

The "tens rule" highlights that the probability of a species becoming invasive is a product of successive low probabilities (). The most effective and cheapest point of intervention is at the very first stage: preventing introduction and escape. Once a species is established or has become a widespread pest, control or eradication becomes exponentially more difficult and expensive. Strict prevention (quarantine, ballast water management) is the most proactive and efficient strategy.

This question tests the precise application of IUCN criteria. The assessment period is the longer of 10 years or 3 generations (90 years). The observed period is 1950-2022 (72 years), within the 90-year window. The population reduction is . Since , the species meets the criteria for Vulnerable (VU) under Criterion A2 (observed decline). The assessment must be based on observed data, not projections, so it does not yet qualify as Endangered.

While all options contribute to India's biodiversity, option C provides the most fundamental biogeographical reason. The convergence of these three massive, historically distinct realms means India has received species from Europe/North Asia (Palaearctic), Africa (Afrotropical), and Southeast Asia (Indo-Malayan). This tectonic and geographic history has created a unique 'melting pot' of biodiversity that is far more significant in explaining its overall richness and uniqueness than area, hotspots, or cultural practices alone.

Let's calculate:

• Alpha () diversity (within-habitat): X has . Y has . So, Y > X.
• Beta () diversity (between-habitat turnover): In X, turnover is complete (no overlap), so is maximum. In Y, there is overlap, so is lower. So, X > Y.
• Gamma () diversity (total landscape): For X, species. For Y, species. So, Y > X.
  Therefore, statement A is the only correct analysis.

This strategy is the most comprehensive and sustainable. Compensation (A) is reactive. Translocation (B) is often ineffective as another leopard occupies the vacant territory. Culling (D) can disrupt social structures and is ethically controversial. Strategy C addresses both the 'pull' factor (easy food source) by making livestock inaccessible and the 'push' factor (lack of natural food) by restoring the wild prey base. This combination reduces the motivation for leopards to enter human areas and provides a durable solution.

While cost, disease, and diet are significant challenges, the most fundamental evolutionary drawback is artificial selection. Natural selective pressures (predation, foraging) are replaced by new pressures (adaptation to enclosures, human presence). Over generations, this leads to genetic changes that favor survival in a zoo but may compromise the animal's ability to survive if reintroduced to the wild. This "domestication selection" is a subtle but profound long-term threat to the conservation value of the captive population.

The Trans-Himalayan zone is a high-altitude desert with sparse vegetation, so deforestation (A) is not the primary issue. Invasive species like Lantana (D) are a problem in warmer, moister zones. The defining human-wildlife interaction in this zone is the conflict between large predators like the snow leopard and the nomadic herders (e.g., Changpa people) whose livelihoods depend on livestock. This conflict, leading to retaliatory killings, is a central conservation challenge specific to the socio-ecological system of the Trans-Himalayas.

The two criteria for a biodiversity hotspot are:

1. Endemism: It must contain at least 1,500 species of endemic vascular plants.
2. Threat: It must have lost at least 70% of its original primary vegetation (i.e., have remaining).
   The region has 1,450 endemic plant species, which is just below the threshold of 1,500. So, it fails the endemism criterion. It has 28% of its vegetation remaining, which means it has lost 72%. This is more than 70%, so it meets the threat criterion. Because it fails to meet one of the two mandatory criteria, it does not qualify as a hotspot.

While A, B, and D are all examples of informational value, they involve extracting a tangible product: a chemical, an enzyme, or a gene. Option C represents a higher level of abstraction. It's not about taking a physical or genetic component, but about learning from the behavior and complex system dynamics of an organism to solve a completely unrelated human problem in computer science. This is a sophisticated form of biomimicry and perfectly encapsulates the concept of nature as a source of ideas and algorithms.

The Allee effect describes a situation where a population's per capita growth rate decreases as its density gets lower. Option C is a perfect example. By removing key matriarchs, the social fabric collapses. Remaining elephants are less efficient at finding resources, defending against predators, and raising young. This social breakdown lowers reproductive success and survival rates for the entire group, causing the population growth rate to plummet, potentially leading to an extinction vortex even if poaching were to stop.

This question probes the core philosophy of the Biosphere Reserve concept. While National Parks are primarily focused on strict preservation, often by creating 'human-free' zones, the MAB philosophy is fundamentally about reconciliation. It posits that humans are part of the ecosystem and seeks to find ways for them to live sustainably within it. The zoned structure (strict protection in the core, research in the buffer, sustainable development in the transition zone) is a physical manifestation of this philosophy of integrating conservation and development.

A "Lazarus taxon" is a species that disappears from the fossil record only to reappear later. Its most critical implication is for conservation practice. It forces us to be more cautious before declaring a species extinct based on a lack of recent sightings. It provides a strong argument for funding exploratory surveys in remote or deep-sea environments and for protecting 'data deficient' habitats, as they may harbor undiscovered or rediscovered species.

This scenario perfectly describes an extinction vortex. The small population size leads to inbreeding and genetic drift. Inbreeding increases the expression of deleterious recessive alleles (inbreeding depression), which lowers survival and reproduction. Genetic drift randomly reduces genetic variation, limiting adaptive potential. This further reduces the population size, which in turn strengthens the effects of inbreeding and drift. This vicious cycle is a positive feedback loop that spirals the population towards extinction.