BIOL 330 Lecture Notes - Lecture 3: Branchial Arch, Clasper, Olfactory Tract
14 Feb 2017
School
Department
Course
Professor
Document Summary
Distinct head end with tripartite brain and cranium complex sense organs. Pharyngeal muscles used in respiration rather than filter feeding: filter feeding = taking water and letting the water pass through the gills. Some 520-480 mya: ostracoder(cid:373)s: s(cid:373)all ja(cid:449)less (cid:862)fishes(cid:863) encased in bony armour (with dermis, small (3 cm), shoft-bodied, (cid:862)fish-shaped(cid:863, cranium, w-shaped myomeres, dorsal fins, no mineralized tissues (eg. myllokumingia, bony-plated, torpedo-shaped jawless fishes, 12-35cm, head shield (eg. astraspis) Found in some early vertebrates (eg. ostracoderms) but not others; not in extant jawless blankets. Early-known types as complex as those in living vertebrates. Small tooth-like elements in the skin: dermal armour (ostracoderms); dermicles (shark skin); homologies with our teeth: protection from predators, stability while swimming, protection/insulation from electroreceptors used in detecting prey, regulation/storage of phosphorus and calcium. Bone is supportive and protective, but is also involved in mineral regulation. Have other vertebrate features (eg. notochord, cranium, myomeres, large eyes) Confirmed to be vertebrates from these features.
