10 public questions tagged with this topic.
Primary succession occurs in lifeless areas, such as newly formed volcanic islands, where no life previously existed.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Life History Variations and Population Interactions - Overview
Primary succession begins on newly formed or exposed surfaces, such as volcanic rock, where no previous life existed.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Responses to Abiotic Factors - Regulate Conform Migrate Suspend
Primary succession is slower because it starts on bare surfaces, requiring soil formation before larger plants can establish.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Organism and Environment - Major Biomes Abiotic Factors
Primary succession begins where a biological legacy and developed soil are absent, as on new lava, exposed bedrock, or recently deglaciated substrate. Colonists must initiate weathering and organic-matter accumulation before a deeper soil and more demanding vascular plants can become established. Successional trajectories emerge from dispersal, establishment, species interactions, and organism-driven environmental change. Priority effects can make arrival order important, while retained soil and propagules strongly accelerate recovery after disturbance. Facilitation, tolerance, and inhibition
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
Ecological succession is directional change in community composition and structure through time, often following formation of new habitat or disturbance. Colonization, local extinction, environmental modification, and species interactions cause one assemblage to replace another; ordinary seasonal fluctuations do not constitute this long-term sequence. Classical succession terminology divides community development into site exposure, arrival, establishment, interaction, environmental reaction, and relative stabilization. Modern ecology treats these as useful descriptions rather than a rigid det
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
Extinction is effectively irreversible because it eliminates the last living members of a species and therefore its unique evolutionary lineage and gene pool. Once no viable individuals or preserved reproductive material remain, ordinary ecological processes cannot recreate that species. Evolution might eventually produce organisms with similar traits, but not the same historical lineage. Succession can reverse or restart after disturbance, invasion can sometimes be controlled or eradicated, and evolutionary change may be altered by future selection or gene flow, though none is always easily r
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
Species interactions are major drivers of succession because organisms change both the physical environment and one another’s probability of establishment and survival. Pioneer plants may facilitate successors by building soil, adding nitrogen, or providing shade. Residents may instead inhibit newcomers through competition, allelopathy, or occupation of space. In tolerance pathways, later species establish independently but ultimately prevail because they survive low light or resources better. Herbivory, predation, mutualism, and decomposition also redirect trajectories. The keyed choice highl
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
A pond progressing toward marsh, meadow, shrubland, and eventually forest under a suitable climate is the classic hydrosere or hydrarch succession. Aquatic plants and phytoplankton add organic matter, while incoming mineral sediment is trapped by vegetation. Decomposition is incomplete in waterlogged conditions, so the basin gradually fills and becomes shallower. Submerged plants give way to floating and emergent vegetation, then sedges, grasses, shrubs, and terrestrial trees as soil aeration improves. Primary succession describes establishment where a prior soil community is absent and can in
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
Odum’s classic strategy of ecosystem development proposes that nutrient cycles become increasingly closed, or “tighter,” as succession proceeds. Early communities have small nutrient pools in biomass, weak retention, and relatively large losses through runoff or leaching. As vegetation, roots, decomposers, and soil organic matter develop, nutrients released by decomposition are captured more efficiently and reused within the community. Longer food chains and greater biological regulation can further slow their escape. Mature systems therefore tend to conserve limiting elements, although distur
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
Species diversity often increases during ecological succession as habitat structure becomes more complex and additional niches develop. Pioneer communities contain relatively few stress-tolerant colonists. Their growth modifies light, temperature, soil, moisture, and organic matter, allowing new plants, decomposers, herbivores, predators, and mutualists to establish. Diversity may later level off or even decline if strong competitors exclude earlier species, so the trend is not universally monotonic. Biomass also usually increases as vegetation accumulates, which makes this item ambiguous beca
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20
