Further Reading / Supplemental Links
- http://www.ucmp.berkeley.edu/chordata/Chordata.html
- http://www.ucmp.berkeley.edu/vertebrates/vertintro.html
- http://en.wikipedia.org/wiki
Vocabulary
cephalization The placement of important sensory organs near or in the head.
cephalochordates Agroupofchordateswithanotochordandnervecordbutnovertebrae.
chordata The phylum of chordates, containing the vertebrates and several closely related
invertebrates.
cranium The braincase or skull.
endostyle A groove or pair of grooves having cilia; located in the pharynx; functions are
to gather food particles and transport them along the digestive tract.
notochord A hollow dorsal nerve cord.
urochordates Agroupofchordateshavinganotochordandnervecordpresentonlyduring
the larval stage.
vertebrata The subphylum of vertebrates, distinguished by having backbones or spinal
columns.
Points to Consider
- The notochord’s stiffness in many chordates may have evolved to facilitate the effec-
tiveness of swimming in S-shaped movements. Think about the advantages this may
have for water-living vertebrates. - Unlikechordateswithcephalization,cephalochordates(lancelets)haveamouth,butnot
a well-developed head, and have light-sensitive areas along their entire back, instead
of at the anterior end of the body. - How do you think cephalization could be an advantage in movement and feeding in
fish?