Speciáció

Speciáció, commonly referred to in English as speciation, is the biological process through which populations evolve to become distinct species. It is a fundamental mechanism of evolution and the primary driver of biodiversity. The concept was first articulated by Charles Darwin and Alfred Russel Wallace in the mid‑nineteenth century and has since become central to modern evolutionary biology.

Two major categories of speciation are generally recognized: allopatric and sympatric. Allopatric speciation occurs when physical barriers, such as mountain ranges or bodies of water, separate populations and prevent gene flow. Over time, genetic drift, mutation, and natural selection in the isolated populations lead to reproductive isolation. Sympatric speciation, by contrast, occurs within a single geographic area. Mechanisms such as polyploidy in plants, chromosomal rearrangements, or ecological niche differentiation can reduce interbreeding among subsets of a population.

Reproductive isolation, the key outcome of speciation, can be pre‑zygotic (e.g., behavioral differences, temporal isolation) or post‑zygotic (e.g., hybrid inviability or sterility). The formation of a new species is a gradual process, often requiring many generations and complex interactions between genetic, ecological, and behavioral factors.

Speciation events are documented in the fossil record and are inferred from molecular phylogenies. Whole‑genome analyses and comparative studies of developmental pathways help elucidate the genetic underpinnings of speciation. Understanding speciation is crucial for conservation biology, as it informs efforts to preserve evolutionary potential and maintain ecosystem function.