From Paul Devitt
Your report on the biggest questions in human evolution (24 March, p 34) does not adequately address how the “great leap forward” occurred about 50,000 years ago. From that point on, humans were radically different from their ancestors and other creatures. We assume this had physical or biological causes, such as climate change or genetic mutation; yet our ancestors at that time would have been subject to the same biological and environmental influences as other large mammals.
So how did it come about? Whatever the causes, the change seems to have been unique, as if humans entered a new dimension of being. No other creature that we know of has made such a radical and relatively sudden departure from its predecessors.
Sevenoaks, Kent, UK
