Principios de Taxonomia

2
Why is there a Species Problem?
2.1
Objective of the Book
This book attempts to question the intuitive processes that are often employed in the
classification of biological organisms. The author does not content himself with the
diverse range of living beings being classified according to the principle of order at
all costs. After all, animals and plants are the products of evolutionary processes,
which are governed by natural laws. Animals and plants are not postage stamps.
The problem with biological systematics is that evolution is not a uniform process;
multiple selection processes of different natures play a role. Speciation depends on
environmental conditions and on specific preferences in the choice of mating
partner. Furthermore, speciation also depends on intrinsic properties of organisms
genomes that are unrelated to external conditions such as the environment or partner
choice. Specific transposable elements in the genome that alter mutation rates can
likewise be the cause of increased speciation rates (Prud homme et al., 2006).
Furthermore, not only are the conditions that cause speciation highly heterogeneous,
but the processes referred to as speciation can also be manifold. Organisms
can undergo alterations in traits as well as experience changes in mutual interindividual
connections, leading them to become new species. However, if a population
exhibits changes in traits during the course of evolution, this is not the same
process as when a population loses cohesion by dividing into two separate reproductive
communities (see Chapter 6 and the anagenesis-cladogenesis conflict in
Chapter 7). Individuals that are almost identical with regard to their traits might not
be related to one another. Conversely, closely related individuals can have a markedly
different appearance from one another (Chapter 5). Individuals that have markedly
different appearances can mate with each other. Additionally, individuals that are
almost identical in terms of traits can belong to completely separate reproductive
communities (Chapter 6). How is it possible to unite such different processes into a
common species concept? How is it possible to include the three taxonomically
important classification principles (resemblance of traits, common descent and
connectedness through mutual gene flow) in a consistent system? Can the existence
Do Species Exist? Principles of Taxonomic Classification, First Edition. Werner Kunz.
Ó 2012 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2012 by Wiley-VCH Verlag GmbH & Co. KGaA.
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