Evolution And History

Ardipithecus 149

Anthropologists of Note

Louis S. B. Leakey

Few figures in the history of

paleoanthropology discovered

so many key fossils, received

so much public acclaim, or

stirred up as much contro-

versy as Louis Leakey and his

second wife, Mary Leakey.

Born in Kenya of mission-

ary parents, Louis received

his early education from an

English governess and subse-

quently was sent to England

for a university education.

He returned to Kenya in the

1920s to begin his career

there.

It was in 1931 that Louis

and his research assistant

from England, Mary Nicol

(whom he married in 1936),

began working in their spare

time at Olduvai Gorge in Tanzania,

searching patiently and persistently for

remains of early human ancestors. It

seemed a good place to look, for there

were numerous animal fossils as well as

crude stone tools lying scattered on the

ground and eroding out of the walls of

the gorge.

Their patience and persistence

were not rewarded until 1959, when

Mary found the first fossil. A year later,

another skull was found, and Olduvai

was on its way to being recognized as

one of the most important sources of

fossils relevant to human evolution in

all of Africa. While Louis reconstructed,

described, and interpreted the fossil

material, Mary made the definitive study

of the Oldowan tools, a very early stone

tool industry.

The Leakeys’ important discoveries

were not limited to those at Olduvai. In

the early 1930s, they found the first

fossils of Miocene apes in Africa at

Rusinga Island in Lake Victoria. Also

in the 1930s, Louis found a number

of skulls at Kanjera, Kenya, that show

a mixture of derived and more ances-

tral features. In 1948, at Fort Ternan,

Kenya, the Leakeys found the remains

of a late Miocene ape with features that

seemed appropriate for an ancestor

of the bipeds. After Louis’s

death, Paul Abell, a member

of an expedition led by Mary

Leakey, found the first fossil-

ized footprints of early bipeds

at Laetoli, Tanzania.

In addition to their own

work, Louis Leakey promoted

a good deal of important

work on the part of oth-

ers. He made it possible

for Jane Goodall to begin

her landmark field studies

of chimpanzees; later he

was instrumental in setting

up similar studies among

gorillas (by Dian Fossey)

and orangutans (by Biruté

Galdikas). He set into mo-

tion the fellowship program

responsible for the training

of numerous paleoanthropologists from

Africa. The Leakey tradition has been

continued by son Richard, his wife

Meave, and their daughter Louise.

Louis Leakey had a flamboyant

personality and a way of interpreting

fossil materials that frequently did not

stand up well to careful scrutiny, but

this did not stop him from publicly

presenting his views as if they were

the gospel truth. It was this aspect

of the Leakeys’ work that generated

controversy. Nonetheless, the Leakeys

produced a great deal of work that re-

sulted in a much fuller understanding

of human origins.

© Melville Bell Grosvenor/National Geographic Collection

River accompanied by fossils of forest animals. The name
Ardipithecus ramidus is fitting for an ultimate human
ancestor as Ardi means “floor” and ramid means “root” in
the local Afar language.
Now that the spectacular Ardi specimen has been suffi-
ciently analyzed by the team who discovered her, paleoan-
thropologists are debating her exact place on the human
line. Because the other African apes share a body plan sim-
ilar to one another, many paleoanthropologists expected
the earliest bipeds to resemble something halfway between
chimps and humans. Instead, Ardi shows that these forest
creatures moved in a combination of ways: They moved

across the tops of branches with the palms of their hands

and feet facing downward, and they walked between the

trees on the ground in an upright position. The other

African apes, as we saw in previous chapters, knuckle-walk

on the forest floor and hang suspended below the branches.

In other words, Ardi resembles some of the early Miocene

apes more than she does the living African apes.

This calls into question what the last common ances-

tor of humans and the other African apes looked like.

Does Ardi represent the more ancestral form, with the

other apes evolving independently after they split from

the human line but still converging to the typical African

ape body plan? Or does Ardi represent a new body plan,

characteristic of the earliest bipeds that evolved away from

the African ape plan shared by chimps and gorillas? And

what of Ardi’s relationship to the later bipeds? Until fall

Ardipithecus ramidus One of the earliest bipeds that lived in

forested portions of eastern Africa about 4.4 million years ago.