The Meme Machine

THE BIG BRAIN 69
then of Homo – including Homo habilis, Homo erectus, and most recently Homo
sapiens.
The australopithecines include the famous skeleton Lucy, an example of
Australopithecus afarensis found in Ethiopia by Maurice Taieb and Donald
Johansen and named after the Beatles’ song Lucy in the Sky with Diamonds.
Remains of A. afarensis range from four million to less than two and a half
million years old. Lucy herself is thought to have lived a little over three million
years ago, was about three feet tall and rather ape-like in build with a brain of
about 400–500 cc – not much larger than a modern chimpanzee’s. From fossil
footprints and computer simulations of walking based on fossil bones, it is now
clear that A. afarensis must have walked upright, though probably could not run.
So we follow that bipedalism came long before hominid brains began to grow
significantly in size.
The increase in brain size probably began about two and a half million years
ago, at about the same time (archaeologically speaking) as the beginnings of
stone tools and the transition from Australopithecus to Homo. At this time,
global cooling was transforming much of Africa’s lush forest into woodland and
then into grassy savannah. Adaptation to this new environment is thought to
account for some of the changes leading to Homo. The first species of Homo
was Homo habilis, named the ‘handyman’ because of the primitive stone tools
they made. Australopithecines may have used sticks or stones that they found as
tools, as other apes do today, but H. habilis was the first to chip stones into
specific shapes to use as knives, choppers or scrapers. Their brains were
significantly larger than australopithecine brains at about 600–750 cc.
About l.8 million years ago Homo erectus begin to appear in the fossil record
in Kenya. Homo erectus was taller and had yet bigger brains, about 800–900 cc.
They were the first hominids to travel out of Africa, the first to harness and use
ire, and they survived in some parts of the world until as recently as 100 000
years ago. More recently still, the fossil record becomes much richer but there
are many arguments about the origins of fully modern humans. So-called
archaic Homo sapiens are widely distributed and have brains around 1100 cc,
with somewhat protruding faces and heavy brow ridges, but there are two main
slopes. One type, which seems to have led to modern H. sapiens, appeared in
Africa about 120 000 years ago. The other lived at the same time and finally
died out only about 35 000 years ago – they were the Neanderthals, Homo
sapiens neanderthalensis. They had large brow ridges and protruding faces.
Their brains were possibly even larger than ours and there is increasing evidence
of their use of fire, their culture, and the possibility that they too had language.