Читать книгу Algorithms in Bioinformatics - Paul A. Gagniuc - Страница 14

Microfossils (the imprint left by an organism in stone), stromatolites (layered rocks derived from photosynthetic cyanobacteria remains sedimented over time), sedimentary carbon isotope ratios or molecular fossils derived from cellular and membrane lipids (“biomarkers”), are used for estimations of the origin and diversification of life in the distant past [28]. Data expressed in billions and hundreds of millions of years are particularly subjective and can lead to variations in the literature up to plus or minus half a billion years. These issues are known and must be taken at face value. While timeline estimates may vary, the order of events is particularly objective. Note that timeline disagreements in the paleontology literature rather indicate that evolution has no milestones but trial periods that overlap; some trials more successful and others that we will probably never know about. Nevertheless, the closer the events get to the present, the more reliable the numbers become. Although relative, timeline estimations in paleontology represent a reliable reference system for important past events on our planet.