Page 131 - Introduction to Paleobiology and The Fossil Record

118 INTRODUCTION TO PALEOBIOLOGY AND THE FOSSIL RECORD

Box 5.1 Naming, describing, and classifying fossils

Life is organized in an inclusive hierarchy: small things (species) fit in larger categories, and these fi t

in still larger categories. Early naturalists realized that it was commonplace to be able to identify
broad groups, such as wasps, bats, lizards, grasses or snails, and that within each group were many
different forms, called species. Life did not consist of a random array of species. The similarity of
groups of species suggested two things: first, that a classification system could be drawn up so people

could identify and discuss particular forms without confusion, and second, that perhaps the inclusive
hierarchy meant something.
Taxonomy is the study of the morphology and relationships of organisms. Systematics is the
broader science of taxonomy and evolutionary processes, while classifi cation refers particularly to
the business of naming organisms and identifying the natural hierarchy. When a fossil is described

for the first time, the author must name it. Biologists and paleontologists use a modifi ed version of
the principles established by the Swedish naturalist and scientist Carl Gustav Linnaeus (1707–1778),
often regarded as the founder of systematics. Linnaeus believed that the evident hierarchical order

in nature reflected the mind of God. Others at the time were to see things very differently, and to
speculate about the possibility of evolution, or change through time.
In Linnaean nomenclature a species is given a genus and species name, such as Homo sapiens.
These names are based on words from ancient Latin and Greek and they are printed in italics, fol-
lowed by the author’s name and date of publication. If, subsequently, another scientist moves a
named species to another genus, perhaps because of new observations of similarity, the original
author and date must then be placed in parentheses. Where several named species turn out to be the

same, the subsequent names are identifi ed as synonyms, or aliases, of the first name to have been
given to the form.
When a new species is established, a type specimen is designated, and it is housed in a major
institution, such as a museum or university, accessible to future investigators. The new species is

defined by a short diagnosis, a few lines emphasizing the distinctive and distinguishing features of
the fossil. A fuller description, supported by photographs, drawings and measurements, is also given,
together with information on geographic and stratigraphic distribution.
Fossils, like living animals and plants, are classified in a hierarchical system, where species are

included in genera, genera in families, and up through orders, classes, phyla, kingdoms and
domains.

be preserved and unfavorable ones
EVOLUTION BY NATURAL SELECTION
destroyed.
The night of September 28, 1838 was impor-
tant for Darwin: it was then that he realized On that date he drew a simple branching evo-
the missing piece of the evolutionary puzzle lutionary tree in his notebook, and a more
– natural selection. He wrote in his autobiog- elaborate version was the only illustration in
raphy (Darwin 1859) that, the Origin (see Fig. 5.1b).
Darwin came to his flash of inspiration by

I happened to read for amusement a combination of thoughts and observations:
Malthus on Population, and being well
prepared to appreciate the struggle for • He had seen the huge diversity of life
existence which everywhere goes from during a 5-year long circumnavigation of
long-continued observation of the habits the world on board the Beagle, a British
of animals and plants, it at once struck surveying ship; he asked himself why life
me that under these circumstances was so diverse – every island he visited had
favorable variations would tend to different plants and birds.