Lecture notes
Phylum Chordates
- Module
- BIOL1029
- Institution
- University Of Southampton (UOS)
Lecture notes on Phylum Chordata (part of echinoderms and chordates)
[Show more]
Seller
Follow
Content preview
Phylum Chordata IClosest relatives of chordates are echinoderms. These both had a common ancestor. The third
deuterstome phylum is hemichordates.
We are chordates and chordates appeared in Cambrian era. There were a series of key evolutionary
innovations from early deuterostomes to humans. Below are all the sub phyla that come under
chordata.
All chordates have 4 unique traits at least at some point during their development. Below is a type of
chordate with these 4 traits.
, Notochord is a longitudinal flexible rod that’s located between the nerve cord and digestive tube. It's
made of large fluid filled cells encased in stiff fibrous tissue. Provides support and a flexible structure
for muscles to work against. Its not the same as a vertebral column which replaces notochord in
higher vertebrates.
Dorsal nerve cord develops by the invagination of the dorsal ectoderm. The hollow nerve cord
develops into a CNS.
Pharyngeal slits are slits in the pharynx which allow water to exit the body without going through the
digestive tract. Its used for filter feeding in primitive chordates. Also modified for gas exchange in
lower vetebrates (gills).
Post anal tail is muscular and extends beyond anus. Non chordates have digestive tracts that extends
throughout the body. It provides a propelling force in aquatic species.
Chordates have undergone segmentation multiple times.
Examples of earliest known chordates are Pikaia and Cathaymyrus. They were 3.5 - 5cm long.
CHORDATA SUB PHYLA
Urochordata (sea squirts, tunicates): sessile filter feeders. Only has pharyngeal slits. Their larvae
have nerve cords, notochords and a tail. These disappear quickly during metamorphosis.
Cephalochordata (lancelets): they're plankton feeders which are burrowed in sand. Anterior tip of
nerve cord is swollen (brain).
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller aiswaryamenon. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £5.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
62890 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now