5 public questions tagged with this topic.
NCERT states that fungi comprise more species than the combined total of fishes, amphibians, reptiles, and mammals.
Ref: NCERT Class 12 Biology Chapter 13: Biodiversity and Conservation Species-Area Relationship
Accumulation of genetic differences reflects key principle in quiz on molecular evolution, where evolutionary mechanisms shape genetic variation and adaptation. In this context, Accumulation of genetic differences 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 Accumulation of genetic differences fits helps integrate natural selection, drift and species concepts essential for NEET, CSIR-NET and GATE examinations. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype
Ref: Li, Molecular Evolution, Neutral Theory and Molecular Clocks.
Paul and Anne Ehrlich compared species in an ecosystem to rivets holding an airplane together. Losing a few rivets may produce little visible effect, but continued losses progressively weaken the system and raise the probability of sudden failure. A functional relationship should be interpreted by asking whether change is gradual, buffered, abrupt, or irregular. Gradual loss is consistent with accumulating contributions; an initial plateau suggests compensation; an abrupt drop points to loss of a disproportionately important species; and an irregular curve indicates identity-dependent effects. These are conceptual expectations, not immutable laws. Different ecosystem processes—such as productivity, decomposition, pollination, or resistance—may follow different curves in the same community because they depend on different organisms and interactions. In this context, the keyed term, Rivets on airplane, identifies the relevant mechanism or quantitative relationship and links the observed pattern to its underlying ecological cause. The distinction is testable by measuring changes in organisms, resources, or process rates through time rather than relying on the label alone.
Ref: NCERT Biology Class 12, Ch. 15 Biodiversity and Conservation
Succession models are interpreted from how resident species affect the arrival and replacement of later species. Facilitation occurs when an early colonist improves conditions for a successor; tolerance occurs when later species can invade regardless of earlier occupants and eventually win through traits such as shade tolerance; inhibition occurs when established organisms suppress newcomers until disturbance or death creates space. A statement that an initial species makes the environment more suitable for a later one therefore indicates facilitation. A species able to invade whether another species is present or absent, and then outcompete it, reflects tolerance rather than dependence on facilitation. The keyed response identifies the pairing “Model X: tolerance, Model Y: inhibition” as the incorrect statement, which can be coherent if Model X shows facilitation and Model Y shows tolerance. However, the defining succession diagrams are absent from the spreadsheet extract, so the model labels and key cannot be conclusively checked. The reliable method is to follow the direction and sign of each species interaction rather than infer the model from replacement alone.
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
Facilitation and inhibition describe opposite effects of early colonists on later species. Under facilitation, pioneer species alter a harsh habitat in ways that increase later establishment—for example, by accumulating soil, adding nitrogen, reducing temperature extremes, or creating shade. They may eventually be replaced by species that benefit from those changes. Under inhibition, early occupants make establishment harder through space pre-emption, allelopathy, shading, or resource capture; replacement occurs mainly when residents die, are damaged, or are outcompeted after a disturbance. Therefore, a diagram in which an initial species enables subsequent species represents facilitation, whereas one showing priority effects and suppression represents inhibition. The keyed interpretation assigns the first figure to facilitation and the second to inhibition, which is scientifically consistent if those arrows or replacement patterns appear in the omitted diagrams. Because the spreadsheet row does not include the figures themselves, that mapping cannot be independently verified from the text alone. The biological distinction remains clear: positive modification drives facilitation, while negative effects of residents on newcomers drive inhibition.
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
