from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Lacking a jaw.
from The Century Dictionary and Cyclopedia
- Having no jaws; agnathous; specifically, having no lower jaw, as a lamprey or hag.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. of animals having no jaw
The containing group of jawed vertebrates and jawless fishes is vertebrata.
In going from amphioxus to jawless fish to jawed fish to land vertebrates we see an increase in complexity of the clotting cascade:
Sure, the jawless fish is doing quite well with out Factor V …. but look what it does have.
So, showing that the jawless fish doesn't have Christmas Factor doesn't really do much to his claim.
By examining fossils and DNA, Shubin shows us that our hands actually resemble fish fins, our head is organized like that of a long-extinct jawless fish, and major parts of our genome look and function like those of worms and bacteria.
For example, the first gill arch in jawless fishes like lampreys (and in embryos of jawed vertebrates) corresponds to the jaws in those vertebrates that have them (that is, all modern vertebrates except lampreys and hagfishes).
Even sharks are closer cousins to humans than they are to lampreys and hagfish the only modern survivors of the once thriving and diverse group of jawless fishes but again, we call them all fish.
Lampreys are ancient jawless, scaleless fish that date back 280 million years, and have the highest number of chromosomes of all vertebrates (164-174).
The rear door flew open; a jawless zombie cocked its head at the sight.
Hagfish are wonderfully slimy jawless chordates that have been difficult to raise in the lab—although if you poke a whale corpse rotting in the cold deeps you'll find them swarming everywhere.
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