SUNConferences, Southern African Institute of Industrial Engineering 2013

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Human Evolution from an African Perspective, With Reference to Charles Darwin, Palaeoclimates, and the Problem of Defining a Species
Francis Thackeray

Last modified: 2013-07-01


In 1836, Charles Darwin visited South Africa during his travels around the world on the ship called The Beagle. In 1837 he was already thinking about evolutionary development. He chose to use barnacles to study the concept of species, but realized that boundaries between species were not clear. This problem was expressed in two substantial volumes on barnacles published in 1851 and 1854. There were several reasons why Darwin (1859) delayed the publication of The Origin of Species, in which he recognized the need to quantify the “amount” of difference when species are considered. Thackeray has assessed the degree of difference between specimens using least squares linear regression analysis of measurements of pairs of specimens. This approach has lead to a statistical (probabilistic) definition of a species, and is useful for assessing the degree of difference between hominid specimens from Africa, recognizing that there is no clear boundary between Australopithecus and Homo in the context of palaeoclimatic change between about 1.8 and 2.5 million years ago.