Page 81 - The Restless Earth Fossils

0 Fossils

Man’s place in nature
In the 1690s, the English anatomist Edward Tyson dissected a
chimpanzee for the first time. He was amazed at the structural
similarities between chimps and humans. In 1699, he wrote that
the chimp and human brain bore a “surprising” resemblance to
each other and went on to say, “One would be apt to think, that
since there is so great a disparity between the Soul of a Man, and
a Brute, the Organ likewise in which ’tis placed should be very
different, too.”
Studies by primatologists like Jane Goodall have shown that
chimps demonstrate love, loyalty, jealousy, and other emotions,
as well as complex social relationships and intelligence once
thought to be exclusively human traits. Geneticists have mapped
human and chimp DNA and shown that their genetic codes differ
by as little as 1%. Of course, it is important to note that humans
did not evolve from chimps or any other existing ape. Each of the
primates that share our world possesses its own unique family
tree. Our close physical and genetic similarities do imply that we
shared a common ancestor perhaps 4 to 7 million years ago—not
long ago at all, at least using a geologist’s wristwatch.
Darwin’s arguments for human evolution in The Descent of
Man rested largely on comparative anatomy and similarities in
early development of man and other animals. Human beings
bear structures like wisdom teeth and the little side passage in
the gut, called an appendix, that seem to serve no apparent func-
tion and which sometimes decay or become infected, but these
vestigial organs do reflect past history. These leftover structures
functioned in some way for our animal ancestors and were passed
along the chain of inheritance. Human embryos develop with
tails and gills that echo those used by distant fishy forebears that
swam in Paleozoic seas. Today, those who specialize in studying
human evolution can also examine hundreds if not thousands of
actual fossils our ancestors and close relatives left behind during
the last several million years.
Scientists now place all apes and humans in the same “super-
family” called the Hominoidea. Humans (and their extinct

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