Shifting Paradigms of the Evolution of Cave Life

The unique morphology of cave animals has interested biologists at least since the time of Lamarck. After a number of non-adaptive explanations for the morphology of cave animals, especially with respect to eye and pigment loss, a neo-Darwinian explanation, emphasizing constructive morphological changes rather than losses, was put forward by Barr, Christiansen, and Poulson in the 1960’s. Emphasizing convergent evolution (troglomorphy), this paradigm has recently been challenged, with evidence of divergent selection and the widespread occurrence of morphologically similar species in other subterranean habitats, including ones with abundant food and relatively strong environmental fluctuations. An emerging paradigm emphasizes the central role of darkness in convergent evolution, and the role of habitat size and interspecific competition in divergent evolution of subterranean species.Sprememba paradigme o evoluciji jamskega življenjaEdinstvena morfologija jamskih živali, predvsem v povezavi z izgubo oči in pigmenta, je zanimala biologe že od časa Lamarcka. Kasneje so bile predstavljene tudi druge, t.im. neodarvinistične razlage, s poudarkom na konstruktivnih morfoloških spremembah namesto izgubah, povzete s strani Barra, Christiansena in Poulsona v 60. letih 20. stoletja. Z novejšimi raziskavami o divergentni selekciji in razširjeni prisotnosti morfološko podobnih vrst v drugih podzemeljskih habitatih, vključno s tistimi, kjer je veliko hrane in z relativno velikimi okoljskimi nihanji, se je zamajala paradigma, temelječa na konvergentni evoluciji (troglomorfija). Novo nastajajoča paradigma poudarja osrednjo vlogo teme v konvergentni evoluciji, ter vlogo velikosti habitata in medvrstne kompeticije v divergentni evoluciji podzemeljskih vrst.