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The importance of comparative anatomy
Comparative anatomy explores and establishes the correspondences between body parts of organisms from different species. It builds the concepts of the living structures and thus must not be confused with morphology (the study of the forms and their variations) nor with Evo-Devo (the study of the relations between genetics of the development and evolution). Without comparative anatomy, naming and understanding what can be seen in organisms would be impossible. Then, neither descriptive embryology, causal embryology, phylogeny, palaeontology nor systematics could be conducted and the understanding of both biology and evolution of species would be dead-end streets.
Examining several organisms, we can establish functional correspondences (as between a wing of a fly and one of a pigeon) and correspondences of origin (as for a wing of a fly and one of a mosquito). These must not be confused, because they are different. Comparative anatomy is the study of both the functional adaptation, where the first type of correspondences plays the main role, and the phylogeny, where it is assumed that the second type of correspondences is important.
The study of macrostructures (in recent forms and in fossils) is far to be finished, even on familiar species such a perch (Percidae) or a catfish (Siluridae). The identification and the naming of the bones of the skull of silurids, and those of related forms as clariids, being still uncertain regarding the bones of a perch.
Wels catfish, Silurus glanis, Siluridae.
Neurocranium of a clariid, dorsal view.
European Perch, Perca fluviatilis, Percidae.
In muscles, a huge amount of possible new characters is going to be explored, such as intermuscular bones and ligaments (= transparent rods of the next image), and new functional adaptations are going to be deciphered (Chanet et al., 2004 Chanet.ea.2004).
(Photograph: F. Wagemans (Univ. Liège)).
Today, comparative anatomy uses diverse techniques: classical dissection, examination of skeletons elements, radiographies and images obtained thanks to CT scanning or Magnetic Resonance Imaging (MRI) as on this alcohol preserved mackerel (Scomber scombrus, Scombridae).
(Source : Unité d’Imagerie Médicale et Unité d’Anatomie Comparée (ENVN, Nantes)).