15 public questions tagged with this topic.
NCERT identifies the "Evil Quartet" as habitat loss and fragmentation, overexploitation, alien species invasions, and co-extinctions. Climate change is not included in this list.
Ref: NCERT Class 12 Biology Chapter 13: Biodiversity and Conservation Loss of Biodiversity - Causes - Habitat Loss Overexploitation
Overhunting or natural disasters can drastically reduce population size, leading to a bottleneck effect and loss of genetic diversity.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Life History Variations and Population Interactions - Overview
Number only reflects key principle in quiz on genetic drift, where evolutionary mechanisms shape genetic variation and adaptation. In this context, Number only aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why Number only fits helps integrate natural selection, environment.
Ref: Hartl & Clark, Principles of Population Genetics, Chapter 7: Drift.
Number only reflects key principle in quiz on genetic drift, where evolutionary mechanisms shape genetic variation and adaptation. In this context, Number only aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why Number only fits helps integrate natural selection, environment.
Ref: Hartl & Clark, Principles of Population Genetics, Chapter 7: Drift.
Biodiversity conservation employs two complementary strategies. In-situ conserves species within natural habitats through protected areas like national parks, wildlife sanctuaries, biosphere reserves, and sacred groves where ecological processes continue without relocation. Ex-situ conserves components outside natural habitat when wild survival is jeopardized, involving zoological gardens, botanical gardens, aquaria, seed banks, cryopreservation in liquid nitrogen, tissue culture, and gene banks. Ex-situ provides genetic backup, enables research, captive breeding, and future reintroduction, integrating with in-situ for holistic conservation. This example illustrates how ecological adaptations correlate with biogeographic zonation and conservation prioritization in Indian context.
Ref: NCERT Class 12 Biology Chapter 15 In-situ vs Ex-situ; Campbell Biology Chapter 56 Conservation Strategies
“Umbrella species” for species whose protection helps conserve many other species in the same habitat is termed. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecological interpretation requires separating the immediate process from its broader consequence. A mechanism operating through physiology or behavior can scale up to alter survival, reproduction, abundance, distribution, and community structure. The remaining alternatives—“Indicator species”, “Flagship species”, “Dominant species”—refer to different states, processes, or scales and therefore do not express the same causal relationship. The inference is strongest when the relevant variables, spatial boundary, and time scale are explicit. Context can alter the magnitude of an effect without changing the definition of the focal concept. Linking the wording to measurable consequences for fitness, abundance, or flux gives the conclusion its scientific meaning and prevents a purely mnemonic interpretation.
Ref: NCERT Biology Class 12, Ch. 15 Biodiversity and Conservation
“Protects multiple species in its habitat” for what is the main characteristic of an umbrella species. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecological interpretation requires separating the immediate process from its broader consequence. A mechanism operating through physiology or behavior can scale up to alter survival, reproduction, abundance, distribution, and community structure. The remaining alternatives—“Easily recognizable”, “Indicates pollution”, “Has limited ecological impact”—refer to different states, processes, or scales and therefore do not express the same causal relationship. The inference is strongest when the relevant variables, spatial boundary, and time scale are explicit. Context can alter the magnitude of an effect without changing the definition of the focal concept. This distinction matters because similar surface patterns can arise through different mechanisms, whereas ecological prediction depends on identifying the mechanism that actually changes rates.
Ref: NCERT Biology Class 12, Ch. 15 Biodiversity and Conservation
The keyed exception is “Genetic drift.” In the context of which factor does not affect metapopulation persistence, that statement differs from the governing ecological pattern and must be evaluated against the mechanism rather than accepted from wording alone. Mechanistic support comes from showing how resource limitation, enemies, mate availability, or physiological stress changes demographic performance. A descriptive association alone does not establish regulation or causation. The remaining alternatives—“Number of patches”, “Size of patches”, “Connectivity among patches”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Population ecology links individual births, deaths, immigration, and emigration to changes in abundance. Per-capita rates determine the direction of change, while density dependence creates feedback when crowding alters survival or reproduction. The cited framing is therefore most useful when treated as a conditional biological claim, with assumptions about scale and environmental context kept explicit. Linking the wording to measurable consequences for fitness, abundance, or flux gives the conclusion its scientific meaning and prevents a purely mnemonic interpretation.
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology
“A group of populations linked by immigration and emigration” for a metapopulation is primarily defined as. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Population ecology links individual births, deaths, immigration, and emigration to changes in abundance. Per-capita rates determine the direction of change, while density dependence creates feedback when crowding alters survival or reproduction. The remaining alternatives—“A single large population”, “A group of isolated individuals”, “A population living on a small island”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Interpretation must distinguish absolute population change from a per-capita rate and must state the time interval and population boundary. Age structure, dispersal, environmental variation, and delayed responses can all make observed trajectories depart from a simple model. This distinction matters because similar surface patterns can arise through different mechanisms, whereas ecological prediction depends on identifying the mechanism that actually changes rates.
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology
“Increased fitness with population size” for csir-net: allee effect refers to. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Interpretation must distinguish absolute population change from a per-capita rate and must state the time interval and population boundary. Age structure, dispersal, environmental variation, and delayed responses can all make observed trajectories depart from a simple model. The remaining alternatives—“Decreased fitness at high density”, “Fitness is unrelated to population”, “Death rate is low at low density”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Mechanistic support comes from showing how resource limitation, enemies, mate availability, or physiological stress changes demographic performance. A descriptive association alone does not establish regulation or causation. Field observations could test this account by measuring the proposed driver and the demographic or ecosystem response while controlling plausible confounding factors.
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology
The keyed exception is “Broad geographic distribution.” In the context of which of the following does not increase extinction probability, that statement differs from the governing ecological pattern and must be evaluated against the mechanism rather than accepted from wording alone. Human-driven habitat conversion, exploitation, introduced enemies, pollution, and climate change often interact rather than acting independently. Traits such as slow reproduction or ecological specialization can magnify vulnerability. The remaining alternatives—“High degree of specialization”, “High trophic status”, “Small population size”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Extinction risk rises when abundance, geographic range, or genetic variation becomes small because demographic chance, environmental fluctuations, inbreeding, and rare catastrophes then have disproportionate effects. Correlated losses among subpopulations further weaken regional persistence. Field observations could test this account by measuring the proposed driver and the demographic or ecosystem response while controlling plausible confounding factors.
Ref: Conservation Biology, Primack & Sher, 6th Ed., Ch. 7
“Dodo” for which extinct species is linked to human hunting and invasive species on islands. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. At equilibrium, species identities can continue to turn over even when richness is approximately stable. The model predicts a balance of rates, not an absence of colonization or extinction. The remaining alternatives—“Moa”, “Pyrenean Ibex”, “Passenger Pigeon”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Island biogeography explains species richness as a dynamic balance between immigration and extinction. Immigration generally declines as an island fills with species, whereas extinction rises as more species divide finite area and maintain smaller populations. Field observations could test this account by measuring the proposed driver and the demographic or ecosystem response while controlling plausible confounding factors. This distinction matters because similar surface patterns can arise through different mechanisms, whereas ecological prediction depends on identifying the mechanism that actually changes rates.
Ref: Conservation Biology, Primack & Sher, 6th Ed., Ch. 7
