BIO 100 Exam 3 UPDATED ACTUAL Exam
Questions and CORRECT Answers
Vertebrate - CORRECT ANSWER - Vertebrates have a backbone made of bony vertebrae
surrounding the spinal cord, along with mineralized connective tissue (bone) and other features
like paired fins and a dorsal nerve cord.
Jawless fishes - CORRECT ANSWER - The two jawless fish groups are Myxini (hagfish)
and Petromyzontida (lampreys).
Hagfish slime - CORRECT ANSWER - Hagfish slime expands rapidly and is extremely
strong and flexible, inspiring bio-materials like kevlar and shark defense technologies.
Lampreys impact on Great Lakes - CORRECT ANSWER - Parasitic sea lampreys have
caused significant damage by sucking blood from fish, leading to overpopulation issues and
fishery declines in the Great Lakes.
Class Chondrichthyes - CORRECT ANSWER - Chondrichthyes are cartilaginous fishes
including sharks, skates, rays, and ratfish. The name means 'cartilage fish'.
Elasmobranchs - CORRECT ANSWER - Elasmobranchs include sharks (~400 species)
and skates & rays (~500 species), primarily marine and quite diverse.
Shark liver - CORRECT ANSWER - The large, oily liver aids in buoyancy since sharks
lack swim bladders.
Shark scales - CORRECT ANSWER - Sharks have placoid scales, which are mineralized
dermal tissues, rough and tooth-like.
Shark teeth - CORRECT ANSWER - Shark teeth form from skin as whorls and are not
embedded in jawbones, unlike other vertebrates whose teeth develop in jawbones.
, Shark nostrils and tapetum lucidum - CORRECT ANSWER - Nostrils detect chemical
cues in water (smell). The tapetum lucidum is a reflective layer behind the retina that enhances
vision in low light.
Lateral line system - CORRECT ANSWER - It detects low-frequency water vibrations
(mechanoreception). Also found in ray-finned fishes, lobe-finned fishes, and aquatic amphibians.
Electroreception in sharks - CORRECT ANSWER - To detect electrical fields from prey
muscle contractions and navigate by sensing water temperature differences.
Shark reproduction aspects - CORRECT ANSWER - Slow growth, late maturity, few
offspring, long gestation — content does mention sharks are susceptible to over-harvesting.
Ecological importance of sharks - CORRECT ANSWER - Sharks balance ecosystems by
keeping prey populations and habitats healthy, maintaining vital food webs.
Ray-finned fish group - CORRECT ANSWER - Includes bichirs, gars, bowfin, sturgeons,
paddlefishes, eels, tarpon, bonytongues, and teleosts (~27,500 species), making up almost half of
all vertebrates.
Ray-finned fish scales - CORRECT ANSWER - Ray-finned fish scales are thinner, lighter
dermal derivatives, covered with mucous to reduce drag and protect from pathogens, unlike
rough placoid shark scales.
Operculum and fish gills - CORRECT ANSWER - Operculum is a bony cover protecting
gills. Gills use counter-current flow to efficiently extract oxygen from water.
Swim bladder - CORRECT ANSWER - A gas-filled organ that helps maintain buoyancy
by adjusting gas volume as fish move vertically in water.
Questions and CORRECT Answers
Vertebrate - CORRECT ANSWER - Vertebrates have a backbone made of bony vertebrae
surrounding the spinal cord, along with mineralized connective tissue (bone) and other features
like paired fins and a dorsal nerve cord.
Jawless fishes - CORRECT ANSWER - The two jawless fish groups are Myxini (hagfish)
and Petromyzontida (lampreys).
Hagfish slime - CORRECT ANSWER - Hagfish slime expands rapidly and is extremely
strong and flexible, inspiring bio-materials like kevlar and shark defense technologies.
Lampreys impact on Great Lakes - CORRECT ANSWER - Parasitic sea lampreys have
caused significant damage by sucking blood from fish, leading to overpopulation issues and
fishery declines in the Great Lakes.
Class Chondrichthyes - CORRECT ANSWER - Chondrichthyes are cartilaginous fishes
including sharks, skates, rays, and ratfish. The name means 'cartilage fish'.
Elasmobranchs - CORRECT ANSWER - Elasmobranchs include sharks (~400 species)
and skates & rays (~500 species), primarily marine and quite diverse.
Shark liver - CORRECT ANSWER - The large, oily liver aids in buoyancy since sharks
lack swim bladders.
Shark scales - CORRECT ANSWER - Sharks have placoid scales, which are mineralized
dermal tissues, rough and tooth-like.
Shark teeth - CORRECT ANSWER - Shark teeth form from skin as whorls and are not
embedded in jawbones, unlike other vertebrates whose teeth develop in jawbones.
, Shark nostrils and tapetum lucidum - CORRECT ANSWER - Nostrils detect chemical
cues in water (smell). The tapetum lucidum is a reflective layer behind the retina that enhances
vision in low light.
Lateral line system - CORRECT ANSWER - It detects low-frequency water vibrations
(mechanoreception). Also found in ray-finned fishes, lobe-finned fishes, and aquatic amphibians.
Electroreception in sharks - CORRECT ANSWER - To detect electrical fields from prey
muscle contractions and navigate by sensing water temperature differences.
Shark reproduction aspects - CORRECT ANSWER - Slow growth, late maturity, few
offspring, long gestation — content does mention sharks are susceptible to over-harvesting.
Ecological importance of sharks - CORRECT ANSWER - Sharks balance ecosystems by
keeping prey populations and habitats healthy, maintaining vital food webs.
Ray-finned fish group - CORRECT ANSWER - Includes bichirs, gars, bowfin, sturgeons,
paddlefishes, eels, tarpon, bonytongues, and teleosts (~27,500 species), making up almost half of
all vertebrates.
Ray-finned fish scales - CORRECT ANSWER - Ray-finned fish scales are thinner, lighter
dermal derivatives, covered with mucous to reduce drag and protect from pathogens, unlike
rough placoid shark scales.
Operculum and fish gills - CORRECT ANSWER - Operculum is a bony cover protecting
gills. Gills use counter-current flow to efficiently extract oxygen from water.
Swim bladder - CORRECT ANSWER - A gas-filled organ that helps maintain buoyancy
by adjusting gas volume as fish move vertically in water.
