Filogenetska divergencija (filetski gradualizam) (gore) pokazuje relativno spore promjene tokom geološkihepoha - Isprekidane ravnoteže (dolje) ilustriraju morfološku stabilnost i (rijetko) relativno brze evolucijske promjene.
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^Hadžiselimović R. (1986): Uvod u teoriju antropogeneze. Svjetlost, Sarajevo, ISBN9958-9344-2-6.
^Berlocher, Stewart H. (1998). "Origins: a Brief History of Research on Speciation". u Howard, Daniel J.; Berlocher, Stewart H. (ured.). Endless Forms: Species and Speciation. New York: Oxford University Press. str. 3. ISBN0195109015.