Evidence on Hominine Evolution ......................................................

LECTURE

It gives you some sense of the extreme excitement of ¿ nding 40% of a

skeleton. Paleontologists are used to meager rations. They can get very

excited if they can ¿ nd one tooth or one knucklebone.

L

ike many parts of this course, the modern story of human evolution
is very recent. Even 50 years ago, we had far less information than
we have now. Before completing the story of human evolution, we
need to survey the evidence on which it is based. The evidence falls into
three main categories: archaeological evidence, evidence based on the study
of modern primates, and evidence based on genetic comparisons between
modern species of primates, including ourselves. The most important
evidence comes from surviving remains of our ancestors and the objects
they left behind. Such evidence can tell us much about the physiology of our
ancestors and their diets and lifeways. Some of the most exciting hominine
remains have come from the African Rift Valley, the tectonic tear running
from Mozambique through Tanzania and Kenya to Ethiopia.

In 1974, in Hadar, Ethiopia, Don Johanson and his colleagues found almost
40% of the remains of a hominine individual about three and one-half feet
tall. This is one of the most complete
hominine skeletons ever found. Johanson
christened the remains “Lucy,” because
his team had been listening to the Beatles
song “Lucy in the Sky with Diamonds.”

Lucy illustrates well what skeletal remains
can tell a skillful team of archaeologists.
Radiometric dating of nearby materials
determined that Lucy lived about 3.2
million years ago. Study of the pelvis
showed that Lucy was female. Study of the teeth and other anatomical
features suggested Lucy belonged to the genus of australopithecines (genus
is the next taxonomic level above species) and that she died in her twenties.

Study of the pelvis and the

base of the skull proved

that she was bipedal. In

quadrupedal species, the

spine enters the skull from

behind, not from below.