where?

[211183]

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I want to review this, but I can't think of how to searc hit..
I remember learning it in Bio....


the dev of everything...
i know this is really vague but

i rem learning that first it had no notochord, then pharyngeal gill slits... eventually all this other stuff.... what is that called again? i didn't see it in AP cliffs I don't think.

Also, what anatomy is important to know? Ive noticed a lot of Q's about EARS

 

[Chesnok]

nerve cord you 're looking for ? caudal tail ? lancelet ?

 

[doc3232]

I think we need to know the basics about the eyes and ears...like the functions of it rather than every single part...

For the first thing, I have no idea what you are saying...

 

[211183]

Yes ! that stuff. what would that be referred to if I was googling it. Tunicates and all that stuff...

vertebrate developement? i dont know. I keep googling the separate words togethr and just get random stuff.

 

[funkymonkey]

Not sure what you're saying but all chordates (verts and non verts) have a notochord, pharyngeal gill slits, and a hollow dorsal nerve cord. if that wasn't it sorry!

 

[211183]

No you are exactly right, but I am talking bout the development of how it got to that point....
I remmeber learning that these certain things first showed the gill slits... then these had the next thing...


Is this not necessary for the test? Am I becoming anal and stressing over unneeded info?

 

[tranv117]

embryology.

 

[Contach]

is this what you are talking about:
All chordates have those 4 things during embryology:
1) Dorsal hollow nerve chord
2) Notochord
3) Pharyngeal gill slits
4) post anal tail

Then there are some chordates who still have these: the Lancelets and Tunicates are these. Thus since they still have the notochord as an adult, they cannot develop a vertebrate. An example is an Amphioxus who is a Chordate but not a Vertebrate.

Then if you go "one level up" the closest species to us can be the Echinoderms. Because, like us, they are Deuterostomes. In that when the blastula invaginates forming the blastopore, the blastopore in these Echinoderms as well as Chordates forms the anus, then the mouth develops later. In all other species the blastopore develops into the mouth and the anus develops later (if an anus is present).

Can someone explain how Hagfish and Lamphrey's are related to us? It was something about a cranium but not a vertebrate? But I don't understand where this fits...

 

[211183]

is this what you are talking about:
All chordates have those 4 things during embryology:
1) Dorsal hollow nerve chord
2) Notochord
3) Pharyngeal gill slits
4) post anal tail

Then there are some chordates who still have these: the Lancelets and Tunicates are these. Thus since they still have the notochord as an adult, they cannot develop a vertebrate. An example is an Amphioxus who is a Chordate but not a Vertebrate.

Then if you go "one level up" the closest species to us can be the Echinoderms. Because, like us, they are Deuterostomes. In that when the blastula invaginates forming the blastopore, the blastopore in these Echinoderms as well as Chordates forms the anus, then the mouth develops later. In all other species the blastopore develops into the mouth and the anus develops later (if an anus is present).

Can someone explain how Hagfish and Lamphrey's are related to us? It was something about a cranium but not a vertebrate? But I don't understand where this fits...

thanks thats exactly what i was getting at... glad someone understood my gibberish. helped!

Extra Info :

There are three subdivisions of the chordates:
1. Cephalochordata
2. Tunicata
The cephalochordates and tunicates never develop a vertebral column. They are thus "invertebrates" and are discussed with the other invertebrates. [Link]

3. Craniata The vast majority of chordates have a skull enclosing their brain, eyes, inner ear, etc.). All but one group of these (the hagfishes) also convert their notochord into a vertebral column or backbone thus qualifying as vertebrates.



Vertebrates separated into:
jawless (agnatha)
with jaw (gnathostomata)