• Corpus ID: 29594186

Introduction to the Bilateria and the Phylum Xenacoelomorpha Triploblasty and Bilateral

  title={Introduction to the Bilateria and the Phylum Xenacoelomorpha Triploblasty and Bilateral},
  author={Phylum Xenacoelomorpha},
long the evolutionary path from prokaryotes to modern animals, three key innovations led to greatly expanded biological diversification: (1) the evolution of the eukaryote condition, (2) the emergence of the Metazoa, and (3) the evolution of a third germ layer (triploblasty) and, perhaps simultaneously, bilateral symmetry. We have already discussed the origins of the Eukaryota and the Metazoa, in Chapters 1 and 6, and elsewhere. The invention of a third (middle) germ layer, the true mesoderm… 

Pervasive evolution of tissue-specificity of ancestral genes differentially shaped vertebrates and insects

A vast RNA-seq dataset covering twenty bilaterian species and eight tissues is assembled, selecting a specular phylogeny that allowed both the combined and parallel investigation of gene expression evolution between vertebrates and insects.

Metabolic Cost and Stability of Locomotion in People with Lower Limb Amputation

It is suggested that children under the age of five should be supervised by an adult or preferably two adults to ensure that they do not wander off on their own and harm others.



The nervous system of Xenacoelomorpha: a genomic perspective

A major focus of this research is the origin of ‘cephalized’ (centralized) nervous systems, and how complex brains are assembled from simpler neuronal arrays has been a matter of intense debate for at least 100 years using Xenacoelomorpha models.

How to make a protostome

Almost all new information about morphology and embryology fits the trochaea theory, and the predicted presence of a perioral loop of the blastoporal nerve ring has now been demonstrated in two annelids.

Unravelling body plan and axial evolution in the Bilateria with molecular phylogenetic markers

Key morphological transitions pose a basic difficulty: reconstruction of ancestral traits of derived clades is problematic because of a lack of transitional forms in the fossil record and obscure homologies between ‘ancestral’ and derived groups.

Acoel development indicates the independent evolution of the bilaterian mouth and anus

The hypothesis that the bilaterian mouth and anus evolved simultaneously from a common blastoporal opening is contradicted, and it is suggested that a through gut might have evolved independently in different animal lineages.

Xenoturbellida: The fourth deuterostome phylum and the diet of worms

The phylogenetic position for Xenoturbella is considered in the light of what is known of its genetics, morphology, and ontogeny and what light this might shine on the common ancestor of the deuterostomes and hence on the origins of the chordates.

The unique developmental program of the acoel flatworm, Neochildia fusca.

An understanding of the cell-lineage fate map allows the results of earlier cell deletion studies examining the specification of cell fates within these embryos to be interpreted and reveals the existence of cell-cell inductive interactions in these embryos.

Assembling the lophotrochozoan (=spiralian) tree of life

  • G. Giribet
  • Biology
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2008
This review explores the current knowledge of protostome relationships and discusses progress and future perspectives and strategies to increase resolution within the main lophotrochozoan clades.