Paleontology
Original Article by: Carlton E. Brett, Department of Geological Sciences, University of Rochester, Rochester, New York.
Stephen Jay Gould, Formerly, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts.
Content
• Applications of paleontology
• Systematics and taxonomy
• Evolutionary paleontology
• Biostratigraphy
• Taphonomy
• Ichnology
• Paleoecology and paleoenvironmental analyses
• Biological aspects
• Evolutionary process and life history
• Life properties
• Sketch of life history
• Related Primary Literature
• Additional Reading
Key Concepts
• Paleontologists study the past history of life by analyzing
fossil remains.
• The field of paleontology lies on the boundary between
two disciplines—biology and geology.
• Paleontological applications include systematics/taxono-
my, evolutionary studies, biostratigraphy, taphonomy, ich-
nology, paleoecology, and paleoenvironmental analyses.
• The biological aspects of paleontology support the
evolution of life throughout geologic time.
• The most fundamental fact of paleontology is that
organisms have changed throughout the history of Earth
and that each geological period has its characteristic forms
of life.
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Fig. 1: Fossil ferns of Paleozoic age represented by thin films of carbon.
(Credit: Stephen Reynolds)
The study of life history as recorded by fossil remains. Pale-
ontology investigates the life of the past through analyses of
preserved fossils and their traces (Fig. 1). The term fossil, from
the Latin "fossilis" (digging; dug up), originally referred to a
variety of objects dug from the Earth, some of which were
believed to be supernatural substances imbued with mystical
powers. However, in a modern context, fossils can be defined
as recognizable remains or traces of activity of prehistoric life.
This broad definition takes in a diversity of ancient remains,
but specifically excludes inorganic, mineralized structures,
even those that spuriously resemble life forms (for example,
dendritic patterns of manganese crystals: dendrites), some-
times termed pseudofossils (false fossils).
The definition of fossils makes several qualifying statements.
For example, fossils must be recognizably tied to once-living
organisms, excluding amorphous organic matter such as coal
and petroleum, although these are certainly derived from the
products of organisms and are sometimes referred to as "fossil
fuels." The definition also encompasses two broad categories of
fossils: (1) remains that are primarily skeletal hard parts (body
fossils) and (2) traces of activity that are evidence of behavior
of living organisms (trace fossils). The latter can be broadly
construed to include tracks, trails, burrows, borings, bite and
gnaw marks, fecal remains (coprolites), and gizzard stones
(gastroliths) polished in the digestive activity of dinosaurs. In
addition, certain organisms, especially bacteria, archaeans,
algae, and vascular plants, produce distinctive and unique
organic molecules, whose degraded remnants can be extracted
from sediments and isolated; these biomarkers form a type of
chemical fossil.
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