Walter Garstang theroies>.<

[hiro]

i know some of the theories that suggested by this guy...

the question is asking:
the development of jaws and the development of paired fins. Describe how and when these developments occurred and what advantages they conferred. Include in your deliberations whether characteristics are thought to have been developed for one purpose but then became further modified for other purposes from the echinoderm-like anscestor

i mention the similar features of the primitive chordate (Urochordata)... but how about the question asked above? the jaw and fins.. i guess they may not be evoloved from Urochordata only... but i hv some messy ideas of that....then confused@_at_

help...

[AstusAleator]

jaws are thought to have evolved from the brancial arcs.