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USC BISC 120 Final Exam Trond Sigurdsen
Questions and Answers
What is the largest group of deuterostomes? - ANSWER✔✔-chordates
Chordates are mostly vertebraes or invertebrates? Primitive chordates have this structure - ANSWER✔✔-
They are mostly vertebrates but there are some primitive forms with a notochord
What are the three types of chordates? - ANSWER✔✔-vertebrates, lancelets, tunicates
What is the amphioxus? - ANSWER✔✔-a lancelet
These two are the simplest chordates - ANSWER✔✔-lancelets and tunicates
What do lancelets and tunicates lack? What do they have instead? - ANSWER✔✔-They lack a vertebral
column but have a notochord as juveniles. Adult lancelets also have a notochord
What are the five notable features of chordates? - ANSWER✔✔-dorsal hollow nerve cord, dorsal
supportive notochord, pharyangeal slits/pouches, post-anal tail, myotomes
Where is the nerve cord located in comparison to the notochord? - ANSWER✔✔-The nerve cord is dorsal
to the notochord
What are the pharyngeal slits in lancelets and fish? - ANSWER✔✔-Gill slits
Are adult tunicates motile or sessile? - ANSWER✔✔-sessile
What two openings do tunicates have? - ANSWER✔✔-incurrent and excurrent siphone
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What do large apparatus do tunicates use to filter water? - ANSWER✔✔-the pharynx
Describe the larva of tunicates - ANSWER✔✔-free-swimming with typical chordate characteristics
What does the dorsal hollow nerve cord develop into? - ANSWER✔✔-It develops into the central
nervous system,: spinal cord and brain
How does the dorsal hollow nerve cord originate? What is a byproduct of this process? - ANSWER✔✔-
Originates embryonically as a folding of ectoderm dorsal to the notochord. Also, neural crest cells are
"pinched off" in this process.
What three tissues do neural crest cells give rise to? - ANSWER✔✔-Many bones in the skull, sensory
neurons, and pigment cells in skin (melanocytes)
In vertebrates, the vertebrae form around these two structures - ANSWER✔✔-the notochord and spinal
cord
Vertebrae start as this material and then form this material - ANSWER✔✔-cartilage turns to bone
In many species of vertebrates, the notochord persists through this structure - ANSWER✔✔-the
vertebral column
In humans, a small piece of notochord called the nucleus pulposus is found in this structure? -
ANSWER✔✔-intervertebral disk
This bone protects the brain and sensory system in the head - ANSWER✔✔-the cranium
What are the most primitive/basal vertebrates? What are they considered to be? Why? - ANSWER✔✔-
the hagfish and lamprey. they are cyclostomes because they have no jaw
This is another term for fish - ANSWER✔✔-pisces
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What is the term "fish" traditionally defined as? - ANSWER✔✔-Traditionally very vague; meaning almost
any animal in the seas/fresh water
The term "fish" is now thought of as - ANSWER✔✔-Vertebrata minus Tetrapoda
In cyclostomes, what supports the mouth? What are the teeth made of? - ANSWER✔✔-Mouth
supported by musculature (not skeleton) and teeth made of horny material
Describe the location of fins on cyclostomes - ANSWER✔✔-Fins along the body, but not paired
Describe the skeleton of cyclostomes? What is the important part? What is the rest made of? -
ANSWER✔✔-Skeleton: notochord is an important part, rest is made from cartilage (and relatively
simple),
This group of cyclostomes are considered to be the most primitive surviving vertebrates - ANSWER✔✔-
hagfish (rudimentary vertebrate)
The term for a jawless fish that also includes extinct species like connodonts is - ANSWER✔✔-agnathan
What do hagfish eat? - ANSWER✔✔-They are scavengers who eat rotting fish, dead whales etc.,
sometimes carnivorous
What is a defense mechanism of hagfish? - ANSWER✔✔-Glands along body produce copious amounts of
slime to deter potential predators
Unlike hagfish, lampreys have this structure - ANSWER✔✔-a true vertebral column composed of
cartilaginous vertebrae
Despite having a true vertebral column made of cartilage, the main skeletal support structure of
lampreys is still this - ANSWER✔✔-notochord
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Lampreys are this type of parasite, what do they eat? - ANSWER✔✔-ectoparasites who eat tissue and
drink blood
What are jawed vertebrates called - ANSWER✔✔-gnathostomes
What are the three common components of a gnathostome? - ANSWER✔✔-jaws (skeletal support of
mouth), paired fins (pectoral and pelvic fins), lateral line system (sensory system along the body)
How are jaws believed to have evolved? - ANSWER✔✔-Jaws may have evolved by modifications of
skeletal support (gill arches) of the anterior pharyngeal slits (gill slits). They might have originally been
part of a system for filter feeding and respiration
The development of these two structures allowed for fish to become more active and to bite off chunks
of food. - ANSWER✔✔-jaw and paired fins
What structures compose the lateral line system? What does this system do? - ANSWER✔✔-Fish have
canals in the skin with pores. They also have cupula with sensory hairs (neuromast sensory organs) that
can sense water displacement
What are the four lineages of gnathostomes? - ANSWER✔✔-chondrichthyans, ray-finned fish, lobe-
finned fish, tetrapods
These two gnathostome lineages are considered to be "bony fish" (osteichthyans) - ANSWER✔✔-ray-
finned and lobe-finned fish
Chondrichthyans include - ANSWER✔✔-Sharks, rays, ratfish (chimaera)
What are chondrichthyan skeletons made of? - ANSWER✔✔-cartilage
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USC BISC 120 Final Exam Trond Sigurdsen
Questions and Answers
What is the largest group of deuterostomes? - ANSWER✔✔-chordates
Chordates are mostly vertebraes or invertebrates? Primitive chordates have this structure - ANSWER✔✔-
They are mostly vertebrates but there are some primitive forms with a notochord
What are the three types of chordates? - ANSWER✔✔-vertebrates, lancelets, tunicates
What is the amphioxus? - ANSWER✔✔-a lancelet
These two are the simplest chordates - ANSWER✔✔-lancelets and tunicates
What do lancelets and tunicates lack? What do they have instead? - ANSWER✔✔-They lack a vertebral
column but have a notochord as juveniles. Adult lancelets also have a notochord
What are the five notable features of chordates? - ANSWER✔✔-dorsal hollow nerve cord, dorsal
supportive notochord, pharyangeal slits/pouches, post-anal tail, myotomes
Where is the nerve cord located in comparison to the notochord? - ANSWER✔✔-The nerve cord is dorsal
to the notochord
What are the pharyngeal slits in lancelets and fish? - ANSWER✔✔-Gill slits
Are adult tunicates motile or sessile? - ANSWER✔✔-sessile
What two openings do tunicates have? - ANSWER✔✔-incurrent and excurrent siphone
Copyright ©Stuvia International BV 2010-2024 Page 1/38
,Copyright © KAYLIN 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH NOVEMBER, 2024
What do large apparatus do tunicates use to filter water? - ANSWER✔✔-the pharynx
Describe the larva of tunicates - ANSWER✔✔-free-swimming with typical chordate characteristics
What does the dorsal hollow nerve cord develop into? - ANSWER✔✔-It develops into the central
nervous system,: spinal cord and brain
How does the dorsal hollow nerve cord originate? What is a byproduct of this process? - ANSWER✔✔-
Originates embryonically as a folding of ectoderm dorsal to the notochord. Also, neural crest cells are
"pinched off" in this process.
What three tissues do neural crest cells give rise to? - ANSWER✔✔-Many bones in the skull, sensory
neurons, and pigment cells in skin (melanocytes)
In vertebrates, the vertebrae form around these two structures - ANSWER✔✔-the notochord and spinal
cord
Vertebrae start as this material and then form this material - ANSWER✔✔-cartilage turns to bone
In many species of vertebrates, the notochord persists through this structure - ANSWER✔✔-the
vertebral column
In humans, a small piece of notochord called the nucleus pulposus is found in this structure? -
ANSWER✔✔-intervertebral disk
This bone protects the brain and sensory system in the head - ANSWER✔✔-the cranium
What are the most primitive/basal vertebrates? What are they considered to be? Why? - ANSWER✔✔-
the hagfish and lamprey. they are cyclostomes because they have no jaw
This is another term for fish - ANSWER✔✔-pisces
Copyright ©Stuvia International BV 2010-2024 Page 2/38
,Copyright © KAYLIN 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH NOVEMBER, 2024
What is the term "fish" traditionally defined as? - ANSWER✔✔-Traditionally very vague; meaning almost
any animal in the seas/fresh water
The term "fish" is now thought of as - ANSWER✔✔-Vertebrata minus Tetrapoda
In cyclostomes, what supports the mouth? What are the teeth made of? - ANSWER✔✔-Mouth
supported by musculature (not skeleton) and teeth made of horny material
Describe the location of fins on cyclostomes - ANSWER✔✔-Fins along the body, but not paired
Describe the skeleton of cyclostomes? What is the important part? What is the rest made of? -
ANSWER✔✔-Skeleton: notochord is an important part, rest is made from cartilage (and relatively
simple),
This group of cyclostomes are considered to be the most primitive surviving vertebrates - ANSWER✔✔-
hagfish (rudimentary vertebrate)
The term for a jawless fish that also includes extinct species like connodonts is - ANSWER✔✔-agnathan
What do hagfish eat? - ANSWER✔✔-They are scavengers who eat rotting fish, dead whales etc.,
sometimes carnivorous
What is a defense mechanism of hagfish? - ANSWER✔✔-Glands along body produce copious amounts of
slime to deter potential predators
Unlike hagfish, lampreys have this structure - ANSWER✔✔-a true vertebral column composed of
cartilaginous vertebrae
Despite having a true vertebral column made of cartilage, the main skeletal support structure of
lampreys is still this - ANSWER✔✔-notochord
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, Copyright © KAYLIN 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH NOVEMBER, 2024
Lampreys are this type of parasite, what do they eat? - ANSWER✔✔-ectoparasites who eat tissue and
drink blood
What are jawed vertebrates called - ANSWER✔✔-gnathostomes
What are the three common components of a gnathostome? - ANSWER✔✔-jaws (skeletal support of
mouth), paired fins (pectoral and pelvic fins), lateral line system (sensory system along the body)
How are jaws believed to have evolved? - ANSWER✔✔-Jaws may have evolved by modifications of
skeletal support (gill arches) of the anterior pharyngeal slits (gill slits). They might have originally been
part of a system for filter feeding and respiration
The development of these two structures allowed for fish to become more active and to bite off chunks
of food. - ANSWER✔✔-jaw and paired fins
What structures compose the lateral line system? What does this system do? - ANSWER✔✔-Fish have
canals in the skin with pores. They also have cupula with sensory hairs (neuromast sensory organs) that
can sense water displacement
What are the four lineages of gnathostomes? - ANSWER✔✔-chondrichthyans, ray-finned fish, lobe-
finned fish, tetrapods
These two gnathostome lineages are considered to be "bony fish" (osteichthyans) - ANSWER✔✔-ray-
finned and lobe-finned fish
Chondrichthyans include - ANSWER✔✔-Sharks, rays, ratfish (chimaera)
What are chondrichthyan skeletons made of? - ANSWER✔✔-cartilage
Copyright ©Stuvia International BV 2010-2024 Page 4/38
