USABO BIOSYSTEMATICS TEST
QUESTIONS WITH ALL CORRECT
SOLUTIONS GRADED A+
Chordata (lancelets, tunicates, vertebrates) - Answer-Coelomates with notochord;
dorsal, hollow nerve cord; pharyngeal slits; post-anal tail
Cephalochordata (lancelets) - Answer-Basal chordates; marine suspension feeders that
exhibit four key derived characters of chordates
Urochordata (tunicates) - Answer-Marine suspension feeders; larvae display the derived
traits of chordates
Myxini (hagfishes and relateives) - Answer-Jawless marine organisms; have head that
includes a skull and brain, eyes, and other sensory organs
Petromyzontida (lampreys) - Answer-Jawless vertebrates; typically feed by attaching to
a live fish and ingeting its blood
Chondrichthyes (sharks, rays, skates, ratfishes) - Answer-Aquatic gnathostomes; have
cartilaginous skeleton secondarily envolved from an ancestral mineralized skeleton
Actinopterygii (ray-finned fishes) - Answer-Aquatic gnathostomes; have bony skeleton
and maneuverable fins supported by rays
Actinistia (coelacanths) - Answer-Ancient lineage of aquatic lobe-fins still surviving in
Indian Ocean
Dipnoi (lungifhses) - Answer-Freshwater lobe-fins with both lungs and gills; sister group
of tetrapods
Amphibia (salamanders, frogs, caecilians) - Answer-Have four limbs descended from
modified fins; most have moist skin that functions in gas exchange; many live both in
water (as larvae) and as land (as adults)
Reptilia (tuataras, lizards and snakes, turtles, crocodilians, bird) - Answer-One of two
groups of living amniotes; have amniotic eggs and rib-cage ventilation, which are key
adaptations for life on land
QUESTIONS WITH ALL CORRECT
SOLUTIONS GRADED A+
Chordata (lancelets, tunicates, vertebrates) - Answer-Coelomates with notochord;
dorsal, hollow nerve cord; pharyngeal slits; post-anal tail
Cephalochordata (lancelets) - Answer-Basal chordates; marine suspension feeders that
exhibit four key derived characters of chordates
Urochordata (tunicates) - Answer-Marine suspension feeders; larvae display the derived
traits of chordates
Myxini (hagfishes and relateives) - Answer-Jawless marine organisms; have head that
includes a skull and brain, eyes, and other sensory organs
Petromyzontida (lampreys) - Answer-Jawless vertebrates; typically feed by attaching to
a live fish and ingeting its blood
Chondrichthyes (sharks, rays, skates, ratfishes) - Answer-Aquatic gnathostomes; have
cartilaginous skeleton secondarily envolved from an ancestral mineralized skeleton
Actinopterygii (ray-finned fishes) - Answer-Aquatic gnathostomes; have bony skeleton
and maneuverable fins supported by rays
Actinistia (coelacanths) - Answer-Ancient lineage of aquatic lobe-fins still surviving in
Indian Ocean
Dipnoi (lungifhses) - Answer-Freshwater lobe-fins with both lungs and gills; sister group
of tetrapods
Amphibia (salamanders, frogs, caecilians) - Answer-Have four limbs descended from
modified fins; most have moist skin that functions in gas exchange; many live both in
water (as larvae) and as land (as adults)
Reptilia (tuataras, lizards and snakes, turtles, crocodilians, bird) - Answer-One of two
groups of living amniotes; have amniotic eggs and rib-cage ventilation, which are key
adaptations for life on land
