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It
is important to remember that the contemporary field of evolutionary biology is
a made up of several diverse sub-disciplines: palaeontology, molecular biology,
population genetics, and developmental biology, to name just a few. Each of
these sub-disciplines is constantly being revised and expanded. Together they
attempt to provide a scientific account of how life first appeared, how the
diversity of living creatures that we see around us today came to inhabit the
Earth, and the detailed functioning of these living beings and the relations
between them. If we include recent work in sociobiology and evolutionary
psychology, then the explanatory reach of evolutionary biology extends to the
day-to-day behaviour of human individuals and societies. This is a broad and
developing family of disciplines. Nevertheless, Darwin’s theory of natural
selection remains a unifying organising principle that is common to them all.
The
scope of the explanations provided by the various sub-disciplines and the force
with which they are held to be final and authoritative varies considerably. On
the one hand, palaeontology provides an impressive but incomplete account of
the evolutionary pathways along which many organisms have travelled in order to
reach their present form. Due to the scarcity of fossils, much of palaeontology
remains tentative. For the foreseeable future we can expect new data and new
fossil finds will lead to revisions of classifications and the historical
timeline. On the other hand, it is difficult to see how Darwin’s idea of
natural selection could ever be supplanted in those sub-disciplines which are
concerned with changes in populations.
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| Feedback | Contributed by: Adrian Wyard
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