It is fitting that this book on Teaching Human Variation appear in 2009, for this year marks the bicentenary of the birth of Charles Darwin and the sesquicentenary of the publication of The Origin of Species by Means of Natural Selection. The concept of Natural Selection was put forward as a mechanism to explain how evolutionary change might have occurred. We owe the hypothesis to Charles Darwin and Alfred Russel Wallace. Independently they had lighted upon it and their preliminary essays were presented to a meeting of the Linnean Society in London on 1st July 1858. All teaching of biological variation should start by reference to evolution and what Wallace, in an act of extraordinary generosity, proposed should be called Darwinism. This book is expected to be published just 150 years after The Origin of Species first saw the light of day. There can be no comprehensive teaching of human variation without its being seen as a function of time. Deep time is the domain of evolutionary change, or phylogeny, the direct evidence for which is for the most part the palaeontological record in the rocks making up the crust of the earth.
Recent time refers to more recent archaeological and fossil remains and to living peoples and their ontogeny. Human variation has a history of over 5 million years and, on the latest calculations, perhaps of 10 million years.