Earth Sciences 2266F/G Lecture Notes - Lecture 4: Agnatha, Cambrian Explosion, Chondrichthyes
26 Jul 2016
School
Department
Course
Professor
Document Summary
Lamprey (jawless fish, with sucking disc with teeth lining the round disc) is a parasite, sucking on a fish for its blood. This is the earliest known living jawless fish. Some people think the conodonta aren"t true vertebrae, so from d and onwards those are true vertebrates. Only 2 survivors related to jawless fish (lamprey + hagfish) Teeth are multi-cusped (multiple prongs); there are rows of teeth. We do have fossils of early cartilaginous fish. Earliest fossils have cartilage (cambrian, silurian), no mineralized anatomic skeleton; they may have armours but vertebrae and fins are not mineralized. Buffer is important b/c for mammals, when the mother is nursing a baby, most of the ca came from the mother (she gives ca from her own bones) Function of mineralized bone cannot be for movement b/c beginning, only part of it is mineralized.
