Tool use by our early ancestors is one such adaptation.
Once multicellular organisation became possible as atmospheric oxygen levels rose, the early multicellular organisms rapidly diverged into many adaptive forms.
methods rely on characteristic faunal and geological patterns to bracket the period when the fossil existed.
At the onset of the 20th century, most scientists had accepted the great antiquity of the earth, the theory of evolution and that humanity had evolved from an ape ancestor, but by 1908 the fossil evidence of early man was scarce.
is heritable) and arises through processes such as mutation and recombination.
Scientists now have accurate methods (see below ) for dating fossils.This formed the foundation of the neo-Darwinian evolutionary theory.Very simply, there are five basic principles to this theory:  Variation has a genetic origin (i.e.erectus (including the Java and Peking hominids - the archetypal Missing Link) and H.sapiens (including Neanderthals and Cro-Magnon) (see the modern taxonomic classification of humans).