10 public questions tagged with this topic.
Species with a Type II survivorship curve, such as birds, experience a constant mortality rate at all life stages.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Population Interactions - Predation and Herbivory
“Narrow niche and limited environmental tolerance” for specialists species are more prone to extinction due to. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Habitat describes where an organism occurs; niche additionally describes how it obtains resources and affects or responds to other organisms. Distribution therefore provides evidence about a niche but is not identical to it. The remaining alternatives—“Broad niche”, “High reproductive rates”, “Generalist diet”—refer to different states, pro
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 13
“Interspecific competition” for realized niches generally become smaller than fundamental niches because of. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. A niche is the multidimensional set of abiotic conditions, resources, and biotic relationships under which a population can persist. The fundamental niche reflects physiological and resource limits, while the realized niche is modified by competitors, consumers, mutualists, and dispersal barriers. The remaining alternatives—“Genetic drift”, “N
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 13
The rescue effect occurs when immigrants enter a small, declining local population and reduce its probability of extinction. New arrivals add individuals directly, can increase reproduction by supplying mates, and may restore genetic variation or reduce inbreeding. The patch remains occupied throughout; immigration “rescues” it before abundance reaches zero. This differs from recolonization, which establishes a population in a patch after local extinction has already occurred. In metapopulation models, both processes depend on connectivity, but they affect occupancy in different ways: rescue l
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 9
An Allee effect occurs when individual performance declines as a population becomes very small or sparse. Individuals may struggle to find mates, cooperate in defense, modify habitat, or avoid inbreeding. Consequently, per-capita fitness rises with density over the low-density range. This positive density dependence is the reverse of the crowding effects emphasized in ordinary logistic regulation. At low density, ordinary competition weakens, but an Allee effect can reverse the expected advantage of rarity. At high density, resource depletion and social interference usually lower performance.
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 5
“Generalist species” for which of the following is least associated with extinction risk. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. 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. The remaining alternatives—“Narrow niche width”, “Top predator status”,
Ref: Conservation Biology, Primack & Sher, 6th Ed., Ch. 7
“Increases extinction risk” for high population size variability. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. 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. The remaining alternatives—“Reduces extinction risk”, “Maintains stability”, “Is unrelated to e
Ref: Conservation Biology, Primack & Sher, 6th Ed., Ch. 7
“High” for reproductive ability reduces extinction risk when it is. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. 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. The remaining alternatives—“Cyclic”, “Low”, “Delayed”—refer to different states, processes, o
Ref: Conservation Biology, Primack & Sher, 6th Ed., Ch. 7
“Species are top predators and hence rare” for high trophic status implies. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. 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. The remaining alternatives—“Species consume only plants”, “Organisms are decomposers”
Ref: Conservation Biology, Primack & Sher, 6th Ed., Ch. 7
Eurythermal species tolerate a broad range of environmental temperatures. Their proteins, membranes, metabolic regulation, stress responses, and behaviour remain functional across wider thermal limits than those of stenothermal species. This breadth allows survival through seasonal fluctuations, movement among contrasting microhabitats, or occupation of geographically variable environments. It does not mean performance is equally high at every temperature. A tolerance curve still contains an optimum, zones of stress, and lethal lower and upper boundaries; eurythermal simply means those boundar
Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10
