1 / 12

Phylum : CHORDATA

Phylum : CHORDATA. WHAT IS A CHORDATE. To be classified into this Phylum, members must have the following characteristics at some point in their development. 1. Hollow Dorsal Nerve Cord. Nerve Cord is now found toward the DORSAL surface of the body rather than Ventrally.

feo
Télécharger la présentation

Phylum : CHORDATA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Phylum : CHORDATA

  2. WHAT IS A CHORDATE To be classified into this Phylum, members must have the following characteristics at some point in their development 1. Hollow Dorsal Nerve Cord Nerve Cord is now found toward the DORSAL surface of the body rather than Ventrally.

  3. It is considered hollow because it has a small channel running down the inside of it, which is filled with spinal fluid Vertebrae Bones have been removed to expose the actual spinal cord with its central canal

  4. 2. A Second characteristics that all chordates must possess at some time in their development is a Post- Anal Tail Post-Anal tail refers to an extension of the most posterior portion of the spine past the anus ANUS

  5. 3. A third key thing that Chordates must possess at some point in their development is Pharyngeal Gill Slits or Pharyngeal Gill Pouches. In Most aquatic chordates, these Pharyngeal (neck) gill slits develop into full working gills and gill slits, but what about for us terrestrial Chordates?

  6. For most terrestrial Chordates these pouch like structures in the Pharyngeal area transform during our embryonic development. They change into structures like our Eustachian tube, Middle Ear structures, as well as give rise to parts of the Parathyroid gland.

  7. 4. The fourth key characteristic is the presence of a NOTOCHORD, but what the heck is a notochord? A NOTOCHORD is a cartilaginous flexible rod that supports the hollow dorsal nerve cord

  8. The reason why you have never damaged or sprained your Notochord, is that in almost all Chordates the Notochord transforms and gives rise to the vertebrae that form our backbone to give better protection to our all important spinal cord. More than 99% of all Chordates that exist now these days have followed this pattern of development and they fit into the major Subphylum : VERTEBRATA. They are called Vertebrates. Including Fish, Amphibians, Reptiles, Birds and Mammals, they all possess a backbone made of Vertebral bones

  9. VERTEBRATES The Majority of our focus will be on the members belonging to Subphylum VERTEBRATA – The “Vertebrates”

  10. This shows the most primitive Chordates over on the left side of the image. These Lancelets (far left) and Tunicates (second from left) do not develop a backbone and therefore do not fit into Subphylum Vertebrata.

  11. TUNICATES (Sea Squirts) LANCELETS Only Exhibit chordate structures in larval stage

  12. Did you know that the Rat is a Chordate?

More Related