Species Concepts And Species Reality Salvaging A Linnaean Rank

¿Qué es la ecología de poblaciones?
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¿Qué es una población?
¿Qué es una especie?
¿Qué es un individuo?
Actividad: concepto de especie y de individuo para 
organismos unicelulares, animales y plantas 
(incluyendo organismos modulares). Se entrega el 
jueves 14 de febrero.

https://dl.dropbox.com/u/74260031/Ecologia‐
FESI_dropbox/Lee_Species_concepts_sp_reality_JEvolBiol2003.pdf

MINI REVIEW

Species concepts and species reality: salvaging a Linnaean rank
M. S. Y. LEE
Department of Environmental Biology, The University of Adelaide and Department of Palaeontology, The South Australian Museum, North Terrace,
Adelaide SA 5000, Australia

Keywords:

Abstract

gene flow;
Linnaean hierarchy;
reproductive isolation;
species category;
species concepts.The validity of the species category (rank) as a distinct level of biological
organization has been questioned. Phenetic, cohesion and monophyletic
species concepts do not delimit species-level taxa that are qualitatively distinct
from lower or higher taxa: all organisms throughout the tree of life exhibit
varying degrees of similarity, cohesion, and monophyly. In contrast, interbreedingconcepts delimit species-level taxa characterized by a phenomenon
(regular gene flow) not found in higher taxa, making the species category a
distinct level of biological organization. Only interbreeding concepts delimit
species-level taxa that are all comparable according to a biologically meaningful criterion and qualitatively distinct from entities assigned to other
taxonomic categories.Consistent application of interbreeding concepts can
result in counterintuitive taxonomies – e.g. many wide polytypic species in
plants and narrow cryptic species in animals. However, far from being
problematic, such differences are biologically illuminating – reflecting differing
barriers to gene flow in different clades. Empirical problems with interbreeding
concepts exist, but many of these alsoapply to other species concepts, whereas
others are not as severe as some have argued. A monistic view of species using
interbreeding concepts will encounter strong historical inertia, but can save
the species category from redundancy with other categories, and thus justify
continued recognition of the species category.

The reality of the species category
Species have long been assumed torepresent important
and irreducible (basal) phylogenetic entities, and thus to
play a unique role in evolution. This view can be traced
back at least as far as Darwin (1859), who equated
evolution with ‘the origin of species’. Many subsequent
books had titles directly asserting the importance of the
species category (rank) in evolutionary processes (e.g.
Dobzhansky, 1937; Cain, 1954; Mayr,1963; Ereshefsky,
1992). However, there has been a long history of dissent,

Correspondence: Michael S. Y. Lee, Department of Environmental Biology,
The University of Adelaide and Department of Palaeontology, The South
Australian Museum, North Terrace, Adelaide SA 5000, Australia North
Terrace, Adelaide SA 5000, Australia.
1 Tel.: 61-8-8207-7568; fax: 61-8-8207-7222;
e-mail:Lee.Mike@saugov.sa.gov.au

the alternative view being that the species category does
not represent a level of biological integration worthy of
special recognition. This view can also be traced back to
Darwin (1859), who despite the title of his most famous
work, stated that the species category did not differ in
any fundamental way from lower ranks such as varieties,
and higher taxa such as genera(e.g. see Ereshefsky,
2001; Hey, 2001). This view continues to attract significant support, with many recent calls for the abandonment of the species rank as a taxonomic category
altogether (e.g. Pleijel, 1999; Ereshefsky, 2000; Mishler,
2 2000; Pleijel & Rouse, 1999, 2000).
There have been very cogent arguments for the
abolition of higher taxon categories such as the genus,
order and class...