The dark side of evolution – how cave animals evolve

Evolucija špiljskih životinja jedinstven je primjer za proučavanje adaptacije organizama na ekstremni okoliš. Špiljski okoliš izrazito je stresan, ističući se uvjetima mraka i manjka hrane koji potiču razvitak specifičnih adaptacija, posebice gubitka očiju i pigmenta. Proučavanjem razvitka ovih, ali i drugih konstruktivnih i regresivnih karakteristika, dobiva se uvid u procese i mehanizme koji potiču evoluciju špiljske faune. Špilje i njeni organizmi predstavljaju model za proučavanje evolucijskih principa kao što su prirodna selekcija, genetički drift, genetski polimorfizmi te fenotipska plastičnost i genetska asimilacija. Ovi mehanizmi djeluju izrazito brzo budući da je prelazak životinja iz vanjskog u špiljski okoliš proces koji donosi velike promjene za organizam, gurajući prema brzom razvitku adaptacija. To čini ovaj model idealnim za proučavanje evolucije općenito, s obzirom na brzinu razvoja adaptacija. Cilj ovog rada jest rasvijetliti mehanizme koje vode do specifične evolucije špiljskih životinja i stjecanja karakteristika gubitka vida i pigmenta.The evolution of cave animals presents a unique example for studying organism's adaptations to an extreme environment. The cave environment is particularly stressful regarding conditions such as the lack of light and food, which in turn drive the development of specific adaptations such as the loss of eyes and pigment. Studying these, and many other constructive and regressive characteristics gives an insight into the processes and mechanisms which push the evolution of cave fauna. Caves and organisms within them represent a model for examining evolutionary principles such as natural selection, genetic drift, genetic polymorphism, phenotypic plasticity, and genetic assimilation. Since entering the cave environment imposes great changes to the organism, these mechanisms have to act fast for these animals to adapt and survive, making caves an ideal model for studying evolution and adaptation. This paper tries to shed some light on the mechanisms leading to the specific evolution of cave animals and the development of adaptations like eye and pigment loss