For example, based on the primate fossil record, scientists know that living primates evolved from fossil primates and that this evolutionary history took tens of millions of years.
By comparing fossils of different primate species, scientists can examine how features changed and how primates evolved through time.
Despite seeming like a relatively stable place, the Earth's surface has changed dramatically over the past 4.6 billion years.
Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.
These methods — some of which are still used today — provide only an approximate spot within a previously established sequence: Think of it as ordering rather than dating.
Biostratigraphy: One of the first and most basic scientific dating methods is also one of the easiest to understand.
A fossil can be studied to determine what kind of organism it represents, how the organism lived, and how it was preserved.
However, by itself a fossil has little meaning unless it is placed within some context.
Before more precise absolute dating tools were possible, researchers used a variety of comparative approaches called relative dating. Du hoffst eine ganz besondere Person für eine heiße sexuelle Beziehung, oder eben ein schnelles Abenteuer zu finden?Melde dich an bei Adult Friend Finder.com, um unsere wachsende Sex-Community zu betreten und dein Bedürfnis nach unglaublichen sexuellen Erlebnissen zu befriedigen.The good dates are confirmed using at least two different methods, ideally involving multiple independent labs for each method to cross-check results.Sometimes only one method is possible, reducing the confidence researchers have in the results. “They’re based on ‘it’s that old because I say so,’ a popular approach by some of my older colleagues,” says Shea, laughing, “though I find I like it myself as I get more gray hair.” Kidding aside, dating a find is crucial for understanding its significance and relation to other fossils or artifacts.