evolution of vertebrates

Question 1

the animals called ______ get their name from vertebrae, the series of bones that make up the backbone

Answer 1

vertebrates

Question 2

-are bilaterian animals that belong to the clade of animals known as Deuterostomia
-include all vertebrates and two groups of invertebrates, the urochordates and cephalochordates

Answer 2

chordates

Question 3

-is a longitudinal, flexible rod
between the digestive tube and nerve cord
-It provides skeletal support throughout most of the length of a chordate
-In most vertebrates, a more complex, jointed skeleton develops, and the adult retains only remnants of the embryonic

Answer 3

notochord

Question 4

-Four key characters of chordates

Answer 4

-Notochord
-Dorsal, hollow nerve cord
-Pharyngeal slits or clefts
-Muscular, post-anal tail

Question 5

-The nerve cord of a chordate embryo develops from a plate of ectoderm that rolls into a tube dorsal to the notochord
-The nerve cord develops into the central nervous system: the brain and the spinal cord

Answer 5

dorsal, hollow nerve cord

Question 6

-grooves in the pharynx develop into slits that open to the outside of the body
-functions: suspension-feeding structures in many invertebrate chordates, gas exchange in vertebrates, develop into parts of the ear, head, and neck in tetrapods

Answer 6

pharyngeal slits of clefts

Question 7

-Chordates have a tail posterior to the anus
-In many species, the tail is greatly reduced during embryonic development
-The tail contains skeletal elements and muscles
-it provides propelling force in many aquatic species

Answer 7

muscular, post-anal tail

Question 8

-(Cephalochordata) are named for their
bladelike shape
-They are marine suspension feeders that retain characteristics of the chordate body plan as adults

Answer 8

lancelets

Question 9

-(Urochordata) are more closely related to
other chordates than are lancelets
-most resemble chordates during their larval
stage, which may last only a few minutes
-draws in water through an incurrent siphon, filtering food particles
-When attacked, tunicates, or “sea squirts,” shoot water through their excurrent siphon

Answer 9

tunicates