Online Digital Library
www.bioscience.pk
Free Downloads Medical Books.
Daily Science
www.bioscience.pk
The Science News app that will get you to the breaking news.

AFFINITIES OF UROCHORDATES

Published in Zoology
Friday, 07 July 2017 12:08
The typical tunicate looks like a non-chordate animal. If the life history of such animal is studied, the larval form reveals the chordate characters of that animal.

In 1816, Lamarck and Cuvier placed these animals in one class ‘Tunicata’. Allis described a compound Ascidian “Botryllus’ in 1756. KowalevskSi. Worked on the development of the Ascidian and placd them in tunicates after observing the chordate features.
 
Urochordates Resemblance With Chordate:
 
  1. Presence of dorsal tubular nerve cord.
  2. Presence of Notochord.
  3. Well developed pharynx with gill-slits.
  4. Presence of endostyle on the ventral side of the pharynx.
  5. Presence of atrium around pharynx.
  6. Presence of post - anal tail, with tail fin.
 
Because of these chordate features tunicates are included in chordates group.

Urochordates Resemblance With Amphioxus:
 
  1. Presence of notochord.
  2. Presence of dorsal tubular nerve cord.
  3. Presence of large pharynx with gill slits.
  4. Presence of atrium and atriopore.
  5. Presence of muscle band.

Thus, the Urochordates show close relation with Cephalochordates.
 
Urochordates Differ With Other Chordates:
 
  1. Presence of retrogressive metamorphosis.
  2. Absence of segmentation.

Because of these characters zoologists included these animals in a separate sub-phylum Urochordates.

During recent years many zoologists regarded the tunicates as primitive and ancestral forms to chordates as a whole.

Useful Sites

  • NCBI

    National Center for Biotechnology Information
  • LTO

    Lab Tests Online® by AACC
  • ASCP

    American Society for Clinical Pathology
  • ASM

    American Society for Microbiology
  • The Medical Library®

    Project of BioScience.pk

Sponsored Links

SiteGround
www.siteground.com
Web Hosting Services Crafted with Care!
BioScience.pk App
www.bioscience.pk
Put vital info into the palm of your hand.
ASH Job Center
www.jobcenter.hematology.org
By American Society of Hemotology
Advertisement

Sponsored Links

SiteGround
www.siteground.com
Web Hosting Services Crafted with Care!
Online Digital Library
www.bioscience.pk
Free Downloads Medical Books.
Make money online!
www.adf.ly
Use a URL shortener service that pays.
Daily Science
www.bioscience.pk
The Science News app that will get you to the breaking news.
ASH Job Center
www.jobcenter.hematology.org
By American Society of Hemotology
BioScience.pk App
www.bioscience.pk
Put vital info into the palm of your hand.

Connect With Us

Contact Us

All comments and suggestions about this web site are very welcome and a valuable source of information for us. Thanks!

Tel: +(92) 302 970 8985-6

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Website: https://www.bioscience.pk

Our Sponsors

Findeen.com

By using BioScience.pk you agree to our use of cookies to enhance your experience on this website.