Unformatted text preview: egments). end of
blocks remnants of
discs cushion your bone two muscle
to a single
vertebra Ostracoderms: heavily armored, extinct jawless fish
with bony plates in the skin, including around the gills •! probably filter feeders and scavengers
•! radiated in Silurian and Devonian (~400 mya) JAWS EVOLVED from bony plates in
the skin that held the gill slits open.
gill supports Anterior gill arches
became modified as
arches added, and
teeth acquired Placoderms: armor-plated predators
with jaws and teeth-like structures •! first jawed vertebrates
•! originated in Silurian, extinct by end of Devonian (360 mya) Some placoderms...
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- Fall '08