Pages: 200
File size: 5.2MB
License: Free PDF
Added: Zolor
Downloads: 82.592

Integrative and Comparative Biology.

Chordate Origin and Evolution

An Ectodermal Novelty 7. The current consensus is that chordates are monophyleticmeaning that the Chordata include all and only the descendants of a single common ancestor, which is itself a chordate, and that craniates ‘ nearest relatives are tunicates.

The solitary enteropneustscommonly known as “acorn worms”, have long proboscises and worm-like bodies with up to branchial chordatrs, are up to 2. List of chordate orders.

An Extension of the New Organizers Hypothesis Pterobranchs ppdf colonial animals, often less than 1 millimetre 0. The Wikibook Dichotomous Key has a page on the topic of: Undergraduate, graduate, and Ph.

The Molecular Evolutionary Road to Vertebrates focuses on echinoderms starfish, sea urchins, and othershemichordates acorn worms, etc. Adult tunicate 1. Uses authors parameter link CS1 maint: University Of Chicago Press. Although the name Chordata is attributed to William Batesonit was already in prevalent use by Some scientists believe that Annelids and arthropods have the closest similarity because of following reasons:. A chordate is an animal belonging to the phylum Chordata ; chordates possess a notochorda hollow dorsal nerve cordpharyngeal slitsan endostyleand a post-anal tailfor at least some chogdates of their life cycle.

If you wish to place a tax exempt order please contact us. During the past two decades, great advances have been made in this field, especially in regard to molecular and developmental mechanisms involved in the evolution of chordates.

Thus in all the above points the chordates differ from all the annulates but resembles Echinoderms and their allies. The nerve chord of the chordate can be easily derived from Echinoderm nervous system and not from the annulates type of nervous system. The Enteropneust Hypothesis and Its Interpretation 9.

The Calcichordate Hypothesis 2. Comparative Genomics of Deuterostomes 5. Collagen and Pharyngeal Cartilage”.

L1_Origin+of+Chordates (1) – 1 Origin of Chordates Kardong…

Their hard, calcified shells keep their bodies well protected from the environment, and these skeletons enclose their bodies, but are also covered by thin skins.

Most are vertebratesin which the notochord is replaced by the vertebral column. A Brief Background 1. Retrieved from ” http: Easily read eBooks on smart phones, computers, or any eBook readers, including Kindle.

Note that this cladogram, in showing the extant cyclostomes hagfish and lamprey as paraphyletic, is contradicted by nearly all recent molecular data, which support the monophyly of the downoad cyclostomes see Ota and Kurakani and references therein for a review of evidence. Urochordata tunicates Ascidiacea sea squirts Appendicularia larvaceans Thaliacea pyrosomes, salps, doliolids.

Satoh and his colleagues have established Ciona intestinalis as a model organism of developmental biology, and he has pdff conducted research of developmental mechanisms involved in the origins and evolution of chordates. The Phylotypic Stage Chordate Features and Molecular Developmental Mechanisms 7. Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following: University of California Museum downloxd Paleontology.

Lepidosauromorpha lizardssnakestuataraand their extinct relatives. Hypotheses on Chordate Origins 2.

Chordate Origin and Evolution | Zoology | Organisms

In other projects Wikimedia Commons Wikispecies. Deuterostomes and Chordates 1. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization. Downnload Nematoda roundworms Nematomorpha horsehair worms.

Views Read View source View history. Arthropoda arthropods Tardigrada waterbears Onychophora velvet worms. Platyhelminthes flatworms Gastrotricha hairybacks.

Chordate – Wikipedia

The majority of animals more complex than jellyfish and other Cnidarians are split into two groups, the protostomes and deuterostomesthe latter of which contains chordates. Kinorhyncha mud dragons Priapulida penis worms.

Sinauer Associates, Sunderland Mass 2nd ed. In the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development. They are also bilaterally symmetric coelomates with metameric segmentation and a circulatory system.