Ardi Our very early ancestor The fossil skeleton of a species,
discovered in Ethipoia in 1994, called Ardipithecus ramidus dated
to 4.4 million years. It belonged to a small- brained, 110 pound
female nicknamed Ardi.
Slide 3
Discoverers proposed that she was a new kind of hominid, the
family that includes humans and our ancestors but not the ancestors
of other living apes. They say that Ardi's unusual anatomy was
unlike that of living apes or later hominids, such as Lucy.
Instead, Ardi reveals the ancient anatomical changes that laid the
foundation for upright walking. Not all paleoanthropologists are
convinced that Ar. RAMIDUS was our ancestor or even a hominid. But
no one disputes the importance of the new evidence. (Science
12/2009 )
Slide 4
A thorough analysis of a large number of collected specimens
shows it is an interesting mosaic of traits: it was bipedal, but
not quite so well adapted to terrestrial locomotion as we are, and
it had feet with an opposable big toe. And of course it had a small
brain, only a little larger than a chimpanzee's. (P.Z. Meyers U of
Minnesota)
Slide 5
But Ardi's feet, pelvis, legs, and hands suggest she was a
biped on the ground but a quadruped when moving about in the trees.
Her big toe, for instance, splays out from her foot like an ape's,
the better to grasp tree limbs. Unlike a chimpanzee foot, however,
Ardipithecus's contains a special small bone inside a tendon,
passed down from more primitive ancestors, that keeps the divergent
toe more rigid. Combined with modifications to the other toes, the
bone would have helped Ardi walk bipedally on the ground, though
less efficiently than later hominids like Lucy. The bone was lost
in the lineages of chimps and gorillas. (National Geographic News
3/1/10)
Slide 6
Slide 7
Slide 8
1974 Donald Johanson finds a 3.2 million year old fossil of a
primate in the Afar Valley region of eastern Africa. (also
Ethiopia)
Slide 9
The cranial capacity is about 1/3 of a modern human, and about
equal to that of a chimp. Its height was also equal to a chimp. The
pelvis and leg bones, however, indicate that The organism was an
upright-walking hominid. (Hominids are the group that comprises
humans and their intermediate ancestors.) It and other specimens of
the same species date about 3-3.9 million years ago. It was
unofficially called LUCY
Slide 10
Lucys Scientific Name = Australopithecus afarensis Lucy stood
only a little over a meter.
Slide 11
The Week February, 2011
Slide 12
Australopithecus africanus (2.3- 3 million) was thought to
descend from A. afarensis. It was taller and heavier, with a
slightly larger cranial capacity.
Slide 13
A.robustus and A. boisei date 1 2.6 million years. They had
heavier skulls and larger teeth. Their general appearance suggests
that they probably descended from Lucys species.
Slide 14
Working in the 1960s, paleoanthropologists working in East
Africa found a hominid skull with a much larger brain case than the
australopithecines. They had larger cranial capacity and were often
found with tools. Their human like morphology resulted in their
grouping under the genus Homo Homo habilis (handy human
-tool-maker) descended from A. afarensis (2.5 1.5 million
years).
Slide 15
Tool marks on animal bones found near H. habilus fossils
suggest that they ate meat.
Slide 16
H. Erectus (upright human) descended from H. habilis.
Apparently the first human to travel out of Africa. They were
originally found in the Pacific Island of Java, and have been found
in China, Europe, and Africa. H. erectus had a thick skull, large
brow ridges, a low forehead, and large, protruding teeth. The brain
was 2/3rds of modern humans.
Slide 17
H. Erectus skeleton: (12 yr old boy) If he had grown to
adulthood, he would have been around 6 feet tall.
Slide 18
Charles Darwin predicted that human ancestors would be found in
Africa. In the 1960s Louis and Mary Leakey discovered fossils in
East Africas Olduvai gorge (Tanzania), that dated as far back as 2
million years. (They had been working there for many years prior to
the 1960s)
Slide 19
They had discovered A.boisei in 1959,and later, H. habilus.
Their son, Richard Leakey and his wife, excavated the earliest
fossils of H. erectus in 1984.
Slide 20
H. sapiens descended from H. Erectus. (H. sapiens consisted of
early, and the modern. The Cro Magnons were an early form of modern
humans. They had a cranial capacity equal to modern humans.) It is
believed that Neanderthals came about at some time during the
existence of early Homo sapiens, but that became extinct.)
Slide 21
Cro Magnon man outlived the Neanderthals and eventually led to
the development of modern humans.