Parade of Men
Scientists in the past, and many
people today still believe, that human evolution was a single-file parade,
with one type of hominid following another in form and time, as shown
here. Based on 150 years of fossil collection and analysis by paleoanthropologists
and other scientists, we now have a more accurate picture of human evolution.
It looks like a race-track or a bush, with as many as four or five hominid
species living on the planet at the same time. Modern humans are not at
the end of a long ladder leading to perfection; we are just the only ones
left standing. Will we last longer than the other hominid species? Only
time will tell...
Footsteps Through Time shows how genes, the environment, and cultural
and technological developments have shaped human bodies and behaviors
and will continue to interact to shape the future of human evolution.
The Footsteps Story follows sixteen moments in time, called Timestones,
and showcases select fossils, but the information is corroborated by thousands
of scientists and numerous fossil finds.
survived and thrived when the dinosaurs became extinct 65 million years
ago after a dramatic climatic change, which marked the beginning of the
Cenozoic era. Primates evolved from a small, shrew-like, tree-dwelling
mammal proto-primate, possibly Purgatorius unio, that shared many features
with true primates. The story fast-forwards to 34 million years ago, when
zeuxis, an ancestor of Old World monkeys and apes, evolved in
the Fayum Depression of Egypt. Old World monkeys (living in Africa and
Asia) and New World monkeys (living in Central and South America) separated
from a common ancestor between 34 and 25 million years ago. Apes were
more common than monkeys 20 million years ago, and were evolving into
a wide variety of species. One of these species was Morotopithecus
bishopi, a primate with a modern ape-like form.
Hominid evolution begins approximately 4.4 million years ago with Ardipithecus
ramidus, the earliest fossils yet found that show evidence of
bipedalism. Fossils from a species named Australopithecus
afarensis, who lived 3.8 to 2.9 million years ago, provide strong
evidence of bipedal walking. Although its brain was small, the position
of the foramen magnum, pelvis, knee, and femur showed that A. afarensis
walked on two legs. Another species, A.
africanus, shared the australopithecine "scene" with
A. afarensis. Fossils of A. africanus such as Mrs. Ples and Taung Child
have been dated to 3 to 2.5 million years ago and show evidence of both
ape-like and human-like features. Australopithecus
aethiopicus also lived 2.5 million years ago. Approximately 2.3
to 1.3 million years ago, Australopithecus
boisei, a type of robust australopithecine, evolved in Africa.
A. boisei had a large sagittal crest on top of its head, large chewing
molars, and a broad, flat face. This species and its other australopithecine
cousins were once widespread all over East Africa, but eventually became
Another group of hominids, now designated as the genus Homo, were evolving
in Africa at the same time as australopithecines. A type of stone tool
technology dated to 2.5 million years ago was first discovered in Olduvai
Gorge, Tanzania. This tool technology, called Oldowan,
was found in the same layers with Homo
habilis/rudolfensis fossils (2.4 to 1.6 million years ago). Homo
ergaster lived 1.8 to 1.5 million years ago and had a larger cranial
capacity as well as a smaller face and teeth than earlier hominids. H.
ergaster probably had the ability to control fire. Homo erectus, a close
relative of H. ergaster, was the first hominid to migrate out of Africa
into parts of Europe and Asia. A transitional species between H. erectus
and H. neanderthalensis (Neandertals) lived in Europe and Asia. This species,
heidelbergensis, split off from H. erectus 800,000 to 250,000
neanderthalensis survived in the cold, harsh climate of Ice Age
Europe from 300,000 to 30,000 years ago. At the same time that Neandertals
were living in Europe, Homo
sapiens evolve from H. heidelbergensis 120,000 years ago in Africa.
These H. sapiens fossils show a high, smooth, rounded skull with a straighter
face and smaller teeth. Fully modern Homo sapiens, known in Europe as
Cro-Magnon, lived throughout the world by 40,000 to 23,000 years ago.
Cro-Magnon is known for cultural achievements such as beautiful cave art,
body ornamentation, and other evidence of symbolic communication. Physical
features of Homo sapiens living today are not much different from those
of Cro-Magnon, but we have had many cultural advances over the last 40,000
years that have significantly changed our daily life and our planet.