prinCiples of evolution 453A B
Equinox Graphics/
Science Source© Frank Vincken, Courtesy of Max Planck Institute for Evolutionary AnthropologyWhen and Where did the genus Homo arise?- The genus Homo arose about 2 million years ago, evidently
in Africa. - Homo sapiens, modern humans, is the only remaining species
in this genus.
taKe-Home messageWherever early Homo sapiens settled, they replaced Homo
erectus populations that had preceded them. Phenotype
differences that we associate with races evolved later.
About 15,000 years ago one small band of humans
crossed a now-submerged land bridge that connected Sibe-
ria with North America. Some 14,000-year-old fossil feces
from a cave in Oregon is reportedly the oldest evidence of
humans in North America.
For the past 40,000 years, cultural evolution has out-
paced biological evolution of the human species—and
so we leave our story. In thinking about this subject,
we can keep in mind that humans spread rapidly over
the planet by devising cul-
tural means to deal with
a wide range of environ-
ments. They also developed
cultural features such as art
and religious beliefs. People
in some parts of the world
still live as “stone age” hunt-
ers and gatherers even as
other groups have moved to
the age of high-tech. These
differences are testimony
to the remarkable behav-
ioral flexibility and depth of
human adaptations.So where did our species, Homo sapiens, arise? Fossils and
genetic studies indicate that anatomically modern humans
originated in Africa between 200,000 and 100,000 years
ago. (The oldest known Homo sapiens fossils come from the
north African nation of Ethiopia.) Some groups of these
people remained in Africa while others left (Figure 23.19).
The ancestors of modern non-African populations trekked
out of Africa between 80,000 and 60,000 years ago. Genetic
evidence shows that early on they met and successfully
bred with Neanderthals. As a result, modern non-African
peoples have a small amount of Neanderthal DNA in their
genomes, whereas Africans do not. Modern humans would
later live alongside Neanderthals in Europe and Asia, but
to date there is no genetic evidence that matings in these
regions contributed to our gene pool.
Figure 23.18 These fossil skulls are from early modern
human forms. A An H. floresiensis skull, and B the skull
of a modern human, H. sapiens. C Svante Pääbo with a
reconstructed Neanderthal skull. Pääbo headed a team
that sequenced the Neanderthal genome in 2010.Figure 23.19 The map shows estimated times when populations of early Homo sapiens were colonizing different
regions of the world, based on radiometric dating of fossils. The presumed dispersal routes (white lines) seem to
support the African emergence model, but other hypotheses have been proposed. (© Cengage Learning)40,000 years ago160,000
years ago60,000
years ago15,000–30,000
years ago35,000–60,000
years agoCave painting made by
early modern humans at
Lascaux, France© Robert Harding Picture Library Ltd/AlamyCCopyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).