Miller and urey's experiments that attempted to recreate conditions on early earth were significant because miller and urey's experiments that attempted to recreate conditions on early earth were significant because they produced the first protocells proved the endosymbiotic theory they showed how radiometric dating could be used to give the absolute ages of rocks and fossils they showed how polymers could form spontaneously on a clay substrate they showed that organic molecules such as amino acids could be produced from inorganic molecules