Every animal is a combination of traits. Some traits are conserved from remote ancestors. Other traits are unique to its branch of the family tree.
The phylum Chordata consists of a majority of species that are vertebrates (with a back-bone) and a minority that are invertebrate chordates. All chordates, at some time in their lives, have four distinctive features:
Urochordata and Cephalochordata and called the invertebrate subphyla. The Vertebrata have a backbone of cartilage or bone and a brain encased in a protective skull.
The vertebrates are divided into eight classes (one of which is extinct).
REVIEW: Only _____ have a notochord, a tubular dorsal nerve cord, a pharynx with slits in the
walls, and a tail extending past the anus.
a. echinoderms
b. tunicates and lancelets
c. vertebrates
d. both b and c
e. all of the above
REVIEW: The only chordate feature still present in the human adult is
REVIEW: Which of the following classes is represented only by fossil forms?
PREVIOUS
NEXT
LECTURE 17 INDEX
MAIN INDEX