inadaptation

Inadaptation is the state in which an organism, population, or trait is poorly suited to its current environment, resulting in reduced fitness, performance, or survival. It reflects a mismatch between phenotype and environment, not merely the absence of adaptation. Inadaptation can arise when environments change faster than evolution, or when traits optimized for one context become disadvantageous under new conditions.

Causes include rapid environmental change, evolutionary lag, developmental or genetic constraints, trade-offs between competing traits, and limited genetic variation or gene flow that impedes adjustment. Phenotypic plasticity can lessen inadaptation, but many traits have fixed or slow responses. Habitat fragmentation or introductions of new species can also create mismatches between existing traits and ecological contexts.

Examples illustrate the concept without implying intentional failure. For instance, warming climates can desynchronize plant flowering times from pollinator activity, reducing reproduction. Animals or populations adapted to a historical niche may perform poorly when conditions shift. Behavioral or physiological traits that were advantageous in one setting can reduce fitness in another. Inadaptation is often regional: a trait may be well suited in one locale but maladaptive elsewhere.

Relation to related ideas: inadaptation differs from maladaptation and from acclimatization. It emphasizes mismatch amid changing environments. Studying it helps explain persistent suboptimal states and the pace of evolutionary change. In practice, reducing inadaptation involves maintaining genetic diversity, promoting habitat connectivity, and allowing populations to track shifting niches.