The Origin and Phylogeny of the Metazoans and the Theory of Endoderm as Secondary Layer (Paperback)Giovanni Pilato (author)
Paperback Published: 23/04/2007
- Not available
The author points out some previously unsolved problems in the other phylogenetic theories. He stresses the misunderstandings in the previous interpretation of the early stages of animal embryogenesis that should have conditioned all previous theories. He indicates that much data, regarding the embryogenesis and the morphology of the adults that leads to the thinking that the endoderm is not a primary embryonic layer but is in fact a secondary layer derived from a primordial ectomesenchyme. This theory, which reverses a cornerstone of the Embryology, allows in addition: the definition, on the ground of a precise criterion, of diploblastic and triploblastic taxa; an explanation of the reason of the blastopore closing even though, soon after, the blastoporal area reopens to form the mouth or the anus; a satisfactory solution to the problem of the origin of the deuterostomes; an explanation of the mouth forming earlier than the digestive cavity in some groups, while in others the contrary occurs; the comprehension of the relationship between ectomesenchyme and endomesoderm; the comprehension of the relationship between the formation mechanisms of the coelom (schyzocoely, syntecocoely, enterocoely); the comprehension of the origin of problematic taxa (Lophophorates and Priapulida) and their relationship with other taxa; and, a satisfactory hypothesis about the origin of the Chordata. The new theory allows a reconstruction of the phylogenesis of the Metazoa that appears to be logical and convincing, and will certainly be the starting point for the a most fruitful debate.
Publisher: Foxwell & Davies (UK) Limited
Weight: 650 g
Dimensions: 280 x 215 x 18 mm
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