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Writing in 2002, Reznick and colleagues reviewed the controversy regarding r/K selection theory and concluded that: The distinguishing feature of the r - and K-selection paradigm was the focus on density-dependent
An isodar, or habitat isodar, is a theory in evolutionary ecology developed in the late 1980s by Douglas W. Morris. [2] [3] Isodars model density-dependent habitat selection for one or two species in two habitats according to the ideal free and ideal despotic distributions.
Density-dependent fecundity. Density-dependent fecundity exists, where the birth rate falls as competition increases. In the context of gastrointestinal nematodes, the weight of female Ascaris lumbricoides and its rates of egg production decrease as host infection intensity increases. Thus, the per-capita contribution of each worm to ...
This theory, based on the assumption of density-dependent selection as the principal forms of selection, results in a fitness landscape that is relatively rigid. A rigid landscape is one that does not change in response to even large changes in the position and composition of strategies along the landscape.
Frequency-dependent selection is an evolutionary process by which the fitness of a phenotype or genotype depends on the phenotype or genotype composition of a given population. In positive frequency-dependent selection, the fitness of a phenotype or genotype increases as it becomes more common.
Many species exhibit density-dependent dispersal and habitat selection. [17] [18] [19] For species exhibiting this pattern, dispersal into what would otherwise be sub-optimal habitats can occur when local abundances are high in high quality habitats (see Source–sink dynamics), thus increasing the size of the species geographic range. An ...
Therefore, when the population density or size hits a number below this threshold, the population will be destined for extinction without any further aid. A strong Allee effect is often easier to demonstrate empirically using time series data, as one can pinpoint the population size or density at which per capita growth rate becomes negative. [1]
Subsequent work has derived the model under other assumptions such as contest competition (Brännström & Sumpter 2005), within-year resource limited competition (Geritz & Kisdi 2004) or even as the outcome of a source-sink Malthusian patches linked by density-dependent dispersal (Bravo de la Parra et al. 2013).