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BIO 220 FINAL EXAM REVIEW QUESTIONS
AND ANSWERS |ALREADY RATED A+ 2025
NEWEST!!!!
What is the function of the notochord? - CORRECT The notochord serves as a site of muscle attachment,
vertebral precursor, and as a midline tissue that provides signals to the surrounding tissue during development.
What is the relationship between surface area and volume? Why is it important? - CORRECT The greater
the surface area-to-volume ratio of an animal, the more heat it loses relative to its volume.
This is important specifically when it come to gas exchange. Humans and other large animals cannot rely on
diffusion to move oxygen and carbon dioxide directly in and out of their body.
Why are living representatives of vertebrate groups not good models of ancestral taxa? - CORRECT
Describe the three major transitions in vertebrate evolution we have discussed so far. -
CORRECT Endoskeleton, cranium - movement
Physiological upgrades - feeding, processing energy
Head, brain and advanced sensory systems - neural crest, ectodermal placodes and doubling of homeobox HOX
genes
What are the other characteristics of the vertebrates that set them apart from the other chordates? -
CORRECT Axial skeleton - cranium + vertebral column*, &
visceral arches
Cephalization - paired sense organs for distance, pressure, & olfactory reception
Neural crest - ectodermal cells parallel to embryonic neural tube; form cranium, cranial nerves, branchial
skeleton, aortic arches, & tri- partite brain
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Integument - ectodermal & mesodermal origin
Closed circulatory system with a ventral heart
Internal metamerism of muscle, skeletal, & nervous systems (1 pr. spinal nerves/myotome)
Muscular pharynx with paired aortic arches
Paired kidneys & gonads
Endocrine system (ductless glands), liver & pancreas as accessory digestive glands
Living endoskeleton made of Ca+ and PO4
What is the most likely candidate for being the first vertebrate? What are the others species that are not as
likely? - CORRECT The most likely candidate for being the first vertebrate is the Conodont.
Others species that are not as likely are the Pikaia and the Haikouella.
What are the earliest undisputed vertebrates? - CORRECT The earliest undisputed vertebrates are the
jawless fish (Ostracoderms).
Illustrate the importance of surface area to volume relationships to describe adaptive variation in vertebrates. -
CORRECT
Describe examples of how surface area to volume ratios influence or constrain the evolution of vertebrate
traits. - CORRECT
Why should we devote half of the semester to vertebrates that are such a small piece of the diversity on earth?
- CORRECT They are big, they are accessible, and they are much more complex than their invert.
counterparts.
What is the significance of the doubling of the HOX genes corresponding to stages of early vertebrate
evolution? - CORRECT Since their large size makes them much more complex, then their genes much be
much more complex to support that.
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What characteristics do hagfish and lampreys share? How do they differ? - CORRECT Hagfish and
lampreysboth lack jaw, lack internal ossification, lack paired fins, & scales.
Hagfish have naked skin with slime glands and accessory hearts.
Lampreys have a disk-like bucal funnel and a long larval stage as an ammocoete. They also have two ore more
pairs of semicircular canals; vertebrate, and extrinsic eye muscles.
How does the life cycle of lampreys differ from that of hagfish? - CORRECT Lampreys have a larval stage
of 3-7 years.
What are the advantages of having jaws? Describe the conditions and evolutionary changes that led to the
development of jaws. - CORRECT They can eat bigger prey.
Jawless fishes were the only vertebrates for about 80 million years. Why such a long period without much
change in the vertebrate lineage? - CORRECT They didn't have any need to change they were the top of
the food chain.
What is a conodont? - CORRECT Conodonts are extinct agnathan chordates resembling eels, classified in
the class Conodonta. For many years, they were known only from tooth-like microfossils found in isolation and
now called conodont elements.
Why were Ostracoderms and Placoderms all heavily armored? - CORRECT To protect themselves from
predators.
What are the synapomorphies of holocephali (chimaeras)? - CORRECT Loss of scales, teeth modified as
grinding plate. Placoid scales; claspers.
Describe the characteristics of skates and rays. What are similarities and differences with sharks? -
CORRECT Skates typically have a prominent dorsal fin while the dorsal fin is absent or greatly reduced in
rays. Most rays are kite-shaped with whip-like tails possessing one or two stinging spines while skates have
fleshier tails and lack spines.
Like sharks, rays don't have a swim bladder, but unlike sharks, they move their pectoral fins when they swim.
Name the various sensory systems in sharks and describe their function? - CORRECT Poor vision
The shark can smell certain substances 10,000 times better than humans, and can locate the smell of prey
accurately over hundreds of meters.
BIO 220 FINAL EXAM REVIEW QUESTIONS
AND ANSWERS |ALREADY RATED A+ 2025
NEWEST!!!!
What is the function of the notochord? - CORRECT The notochord serves as a site of muscle attachment,
vertebral precursor, and as a midline tissue that provides signals to the surrounding tissue during development.
What is the relationship between surface area and volume? Why is it important? - CORRECT The greater
the surface area-to-volume ratio of an animal, the more heat it loses relative to its volume.
This is important specifically when it come to gas exchange. Humans and other large animals cannot rely on
diffusion to move oxygen and carbon dioxide directly in and out of their body.
Why are living representatives of vertebrate groups not good models of ancestral taxa? - CORRECT
Describe the three major transitions in vertebrate evolution we have discussed so far. -
CORRECT Endoskeleton, cranium - movement
Physiological upgrades - feeding, processing energy
Head, brain and advanced sensory systems - neural crest, ectodermal placodes and doubling of homeobox HOX
genes
What are the other characteristics of the vertebrates that set them apart from the other chordates? -
CORRECT Axial skeleton - cranium + vertebral column*, &
visceral arches
Cephalization - paired sense organs for distance, pressure, & olfactory reception
Neural crest - ectodermal cells parallel to embryonic neural tube; form cranium, cranial nerves, branchial
skeleton, aortic arches, & tri- partite brain
, Page |2
Integument - ectodermal & mesodermal origin
Closed circulatory system with a ventral heart
Internal metamerism of muscle, skeletal, & nervous systems (1 pr. spinal nerves/myotome)
Muscular pharynx with paired aortic arches
Paired kidneys & gonads
Endocrine system (ductless glands), liver & pancreas as accessory digestive glands
Living endoskeleton made of Ca+ and PO4
What is the most likely candidate for being the first vertebrate? What are the others species that are not as
likely? - CORRECT The most likely candidate for being the first vertebrate is the Conodont.
Others species that are not as likely are the Pikaia and the Haikouella.
What are the earliest undisputed vertebrates? - CORRECT The earliest undisputed vertebrates are the
jawless fish (Ostracoderms).
Illustrate the importance of surface area to volume relationships to describe adaptive variation in vertebrates. -
CORRECT
Describe examples of how surface area to volume ratios influence or constrain the evolution of vertebrate
traits. - CORRECT
Why should we devote half of the semester to vertebrates that are such a small piece of the diversity on earth?
- CORRECT They are big, they are accessible, and they are much more complex than their invert.
counterparts.
What is the significance of the doubling of the HOX genes corresponding to stages of early vertebrate
evolution? - CORRECT Since their large size makes them much more complex, then their genes much be
much more complex to support that.
, Page |3
What characteristics do hagfish and lampreys share? How do they differ? - CORRECT Hagfish and
lampreysboth lack jaw, lack internal ossification, lack paired fins, & scales.
Hagfish have naked skin with slime glands and accessory hearts.
Lampreys have a disk-like bucal funnel and a long larval stage as an ammocoete. They also have two ore more
pairs of semicircular canals; vertebrate, and extrinsic eye muscles.
How does the life cycle of lampreys differ from that of hagfish? - CORRECT Lampreys have a larval stage
of 3-7 years.
What are the advantages of having jaws? Describe the conditions and evolutionary changes that led to the
development of jaws. - CORRECT They can eat bigger prey.
Jawless fishes were the only vertebrates for about 80 million years. Why such a long period without much
change in the vertebrate lineage? - CORRECT They didn't have any need to change they were the top of
the food chain.
What is a conodont? - CORRECT Conodonts are extinct agnathan chordates resembling eels, classified in
the class Conodonta. For many years, they were known only from tooth-like microfossils found in isolation and
now called conodont elements.
Why were Ostracoderms and Placoderms all heavily armored? - CORRECT To protect themselves from
predators.
What are the synapomorphies of holocephali (chimaeras)? - CORRECT Loss of scales, teeth modified as
grinding plate. Placoid scales; claspers.
Describe the characteristics of skates and rays. What are similarities and differences with sharks? -
CORRECT Skates typically have a prominent dorsal fin while the dorsal fin is absent or greatly reduced in
rays. Most rays are kite-shaped with whip-like tails possessing one or two stinging spines while skates have
fleshier tails and lack spines.
Like sharks, rays don't have a swim bladder, but unlike sharks, they move their pectoral fins when they swim.
Name the various sensory systems in sharks and describe their function? - CORRECT Poor vision
The shark can smell certain substances 10,000 times better than humans, and can locate the smell of prey
accurately over hundreds of meters.
