The Nature of Fossils: A Historical Perspective
Part 1 of 5
Fossils are an integral part of our culture. We encounter fossils
in museums, schools, T.V., and movies. It is hard to believe that
our ancestors were unsure about the nature of fossils.
Throughout
recorded history there have been both naturalistic and super-naturalistic
explanations for fossils. The
Greeks believed
mammoth fossils were the bones of human giants. Xenophanes, a Greek
philosopher, hypothesized that there existed a cycle in which moisture
eroded land into mud followed by another beginning. Xenophanes cited
marine fossils found on land as evidence to support his ideas. Aristotle
speculated that ancient fish swam into cracks in the rock and got
stuck. Crinoids with star-shaped centers were believed to have been
formed by falling stars and ammonites were believed to be decapitated
snakes. The word fossil, which means “dug up”, was coined
during the Renaissance. People wondered, are fossils pranks of nature,
works of the Devil, or supernatural representations of ideal life
forms? Many believed that fossils formed during Noah’s flood.
Leonardo da Vinci recognized that fossil shells in the Apennine Mountains
of Italy were the remains of ancient sea life and argued they could
not have formed during Noah’s flood. He recognized that different
specimens had been formed at different times.
Many people in Western cultures were taught to believe in a literal
interpretation of the Bible. It was natural to believe every species
in existence was made in a single creation event. This idea also
extended to rocks, which were believed to have been formed as we
see them during the first days of creation. Thus in the absence of
two key concepts, extinction and sedimentary rock formation a more
accurate understanding of fossils was not possible.
Robert Hooke (1635-1703) and Niels Stensen (1638-1686) would put
science on a more productive path to understanding the nature and
formation of fossils. Niels Stensen (Latinized to Nicholaus Steno)
was an anatomist and naturalist. After dissecting present day sharks,
Steno realized that the tongue stones, thought to be the tongues
of dragons or snakes, must be ancient shark teeth. He also postulated
that fossilized shells had been made by once living organisms. Steno
thus championed an organic origin of fossils. How could solid fossils
form inside solid rock? Steno hypothesized that fossils encased in
rock must be older than the layers in which they are found. He also
argued that this rock had once been loose and over years had hardened
into sandstone. Through his paleontological studies Steno contended
that sedimentary strata had been deposited in former seas.
Robert
Hooke was an English scientist and inventor. Hooke made some
of the first
accurate illustrations of fossils.
He also suggested
that species may have a fixed “life span” and might be
used to order rocks chronologically. Hooke like Steno championed
the idea that fossils represented ancient plant and animal life.
Hooke and Steno helped to jump-start the science of stratigraphy,
which is the study of rock layers and their fossils. The ideas of
Hooke and Steno would not be accepted for another century.
Continue
to Part 2
Bibliography
for Echoes of Life Through Time
Benton,
M. (2001). Four Feet on the Ground. In Gould, S. [Ed]. The
Book of Life: An Illustrated History of the Evolution of Life
on Earth (pp. 79-126). New York: W.W. Norton & Company,
Inc.
Gould,
S. (2001). Reconstructing (and Deconstructing) the Past. In
Gould, S. [Ed]. The Book of Life: An Illustrated History
of the Evolution of Life on Earth (pp. 6-21). New York:
W.W. Norton & Company, Inc.
Jenkins-Jones, S., Random House Webster's Dictionary of Scientists.
New York: Random House, 1997.
Jones,
S., Darwin's Ghost: The Origin of Species Updated. New
York: Random House, 2000.
Kirk,
G.S. & Raven, J.E., The Presocaratic Philosophers: A
Critical History with a Seclection of Texts. Cambridge University
Press, 1973.
Miller,
K.R., Finding Darwin's God: A Scientist's Search for Common
Ground Between God and Evolution. New York: Harper Collins,
1999.
Milner,
R., The Encyclopedia of Evolution: Humanity's Search for
Its Origins. New York: Facts on File, 1990.
Palmer,
D., Atlas of the Prehistoric World. New York: Random
House, 1999.
Prothero,
D.R., Brining Fossils to Life: An Introduction to Paleobiology.
New York: McGraw-Hill, 1998.
Stanley,
S.M., Extinction. New York: Scientific American Books,
1987.
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