Paleontological evidence of evolution

Kroz mnogo generacija, varijante gena nastale mutacijama prenose se na potomke dajući im nove osobine. S vremenom jedinke postaju sve različitije, a evoluciju pojedinih skupina možemo pratiti proučavanjem fosila, ostataka organizama i tragova njihove aktivnosti sačuvanih u kamenu. Pokazuju nam pojedine korake u evoluciji i daju nam informaciju o tome kako su se pojedina svojstva pojavljivala kroz prošlost. Najraniji oblici života bili su jednostanični. Same stanice nisu nađene u fosilnom zapisu, već nalazimo znakove njihove aktivnosti. U proterozoiku se javljaju prvi višestanični oblici života. Bili su relativno veliki organizmi bez skeleta koji su se mogli kretati, što vidimo iz nađenih ihnofosila. U kambriju organizmi postižu sve veći stupanj kompleksnosti i dolazi do vrlo nagle pojave velikog broja višestaničnih oblika. Tada su vjerojatno nastale sve moderne filogenetske linije životinja. Tijekom ordovicija pojavljuju se prvi pravi kralježnjaci, a nastaju i fosili prvih kopnenih biljaka, najčešće spore. U devonu nalazimo rane predstavnike recentnih biljaka koji razvijaju kompleksni provodni sustav, lišče i sjemenke te počinju rasti u veličine modernih stabala, dok kralježnjaci po prvi put naseljavaju kopno. Organizmi karbona i perma prolaze kroz visok stupanj diverzifikacije i pojavljuju se mnoge recentne skupine, među kojima su i sinapsidi, rana skupina gmazova iz koje su nastali sisavci. Kroz mezozoik možemo naći fosile svih velikih modernih skupina životinja. Nađen je i jedan od najpoznatijih fosila, Archaeopteryx, koji je prijelazni oblik između gmazova i ptica. Biljke razvijaju plod, a pojavljuju se i fosili placentalnih sisavaca, trenutačno dominantne skupine na Zemlji.Through many generations, gene variants caused by mutation, are transferred to descendants giving them new characteristics. With time, differences between organisms become more pronounced and we can follow their evolution by studying fossils, remnants of organisms and proofs of their activity preserved in stone. They show us individual steps of evolution and give us information about when each of the characteristics appeared throughout history. Earliest life forms were unicellular. Cells themselves were not found, but we do find signs of their activity. Multicellular life forms appear in Proterozoic. They were relatively large organisms without skeletons that were mobile, which we see from ichnofossils. In Cambrian period, organisms are getting more complex and there is a sudden appearance of myriad of organisms. All modern phylogenetic lines were probably formed then. During Ordovician, first vertebrates appear and we can find first plant fossils, mostly spores. Early representatives of modern plant groups appear in Devon, they develop complex conductive tissue, leaves and seeds and are growing to modern trees sizes, while vertebrates transition on land for the first time. Carboniferous and Permian organisms are subjected to high degrees of diversification and many modern groups appear, including synapsids, early reptile group from which mammals eventually evolved. Fossils of all modern animal groups appear during Mesozoik. Archaeopteryx, one of the most famous fossils ever discovered, appeared during that period and is a transitional form between reptiles and birds. Plants develop fruits and placental mammals are starting to appear, currently dominant group of organisms on Earth