fossil known 4S “Lucy,”
4zsが6272の27がecz4S の27e2S7s from 3.2 mmillion years ago
Thcsc MRDSHIR. Lucy was a 1ot jike a impenzeeGc
(hat shc Co計時ISHII Sightly bigger brain. Her skin was
not preserved, but _She Was probably covered with far.
However, between two and three millions years ago Our_ancestors began
to inhabit more open savannahs meant the 1
e oO 8 y were out 后 fe sum
ーー) 『
glaring heat for many more hours each day.
Around the same time, they also started to hunt and eat more meat
and game animals were more abundant in the open. This move into open
Spaces offered an explanation for our lack of hair.
Im the 1990s, Peter Wheeler of Liverpool John Moores University im the
UK came up with a mathematical model showing how much excess heat
⑧
hominins would need to lose in open habitats in order to function。 HE their
brains got too hot their thought processes would 0 PA
If the hominins were covered in hair, they could not have lost heat fast
enough. Wheeler reasoned that ( 10 ) allowed our ancestors to keep
cool.
One was an upright gait. Walking on two legs meant that only the tops
of their bodies were under direct sunlight.
But the hominins also started running long distances. This meant they
ould bring down large garme animals by running them to exhaustion, but
