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.
Biologists included principles from genetics in evolutionary theory during the 1920s and 1930s.
Once multicellular organisation became possible as atmospheric oxygen levels rose, the early multicellular organisms rapidly diverged into many adaptive forms.
Mass extinction events and an organism's unique adaptations mark the history of evolution, both of which may lead to adaptive radiation.
God first completed the physical and biological constitution of humanity.Only after this, did God breathe his Spirit into Adam.There are thus two aspects of the human personality, the physical constitution and the spiritual constitution.Archaeological geology as a science had to precede the proposal of evolution, as an understanding of the immense age of the earth is necessary to understand evolution.Cuvier established amongst the scientific community the fact of extinction.