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Evolution and Phylogeny of Chordates

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Encyclopedia of Neuroscience

Synonyms

Phylogeny; Phylogeny and evolution of chordates

Definition

Chordates are the group of animals to which vertebrates including humans belong. Like so many other phyla of bilaterian animals, they originated in the ocean over 520 million years ago, before or during the Cambrian period. Their early evolution is of interest to neuroscientists because this was when the basic structure of the vertebrate brain and spinal cord was assembled. Early chordates were soft-bodied so they seldom fossilized, but we reconstruct their origin using the modern chordates and their relatives plus some miraculously preserved fossils.

Living chordates consist of three subgroups: (i) the vertebrates (informally, the fishes, amphibians, reptiles and mammals), (ii) cephalochordates (also known as amphioxus or lancelets) and (iii) tunicates (or urochordates, including “sea squirts”). Representatives of these three subgroups are shown in Figs. 1 and 2. The chordates belong to a larger group of animals...

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Author information

Authors and Affiliations

  1. School of Biological Sciences, Washington State University, Pullman, Washington, WA, USA

    Jon Mallatt

Authors
  1. Jon Mallatt
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Editor information

Editors and Affiliations

  1. Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, Washington, USA

    Marc D. Binder

  2. Department of Cell Biology and Anatomy, Graduate School of Medicine University of Tokyo Hongo, Bunkyo‐ku, Tokyo, Japan

    Nobutaka Hirokawa

  3. Göttingen, Germany

    Uwe Windhorst

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© 2009 Springer-Verlag GmbH Berlin Heidelberg

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Mallatt, J. (2009). Evolution and Phylogeny of Chordates. In: Binder, M.D., Hirokawa, N., Windhorst, U. (eds) Encyclopedia of Neuroscience. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-29678-2_3116

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