ZOOL 250 Final Exam Questions and Answers with Verified
Solutions | Latest 2026 Update
Q: Gnathifera
Answer:
- Complex pharyngeal jaws
Non-molting
Can't regenerate lost body parts
No asexual reproduction through fission
Non-living out covering
Q: Phylum Aschelminthes
Answer:
- Roundworms
Pseudocoelomate
Eutely (number of cells fixed at adulthood, cells increase in size for growth)
Q: Phylum Rotifera
Answer:
- "Wheel-bearing"
Mastax and trophi (jaw)
"Toes" with adhesive gland
Q: Corona (two lobes covered in cilia)
Answer:
creates water current, brings in food particles, respiration, locomotion
Protonephridia
Syncytial epidermis (support and protection)
Gonochoristic
Looping (adhesive toes, mouth as suction cup)
Cryptobiosis (withstand harsh conditions)
Q: Class Seisonidea
Answer:
- Ectoparasitic on crustaceans
,Reduced corona
Q: Class Bdelloidea
Answer:
- Males have never been observed
Reproduce through parthogenesis (diploid egg develops directly into females)
0 0 Free living and motile
Q: Class Monogonata
Answer:
- Free living and motile (some sessile)
Facultative parthenogenesis (can alternate with sexual reproduction)
Q: Phylum Acanthocephala
Answer:
- Spiny head
Endoparasites (vertebrates = definitive, crustacean = intermediate)
Ligament sacs
Proboscis with hooks
Syncytial epidermis
Spiny proboscis (functions like scolex)
Body regions = proboscis, neck, trunk
Gonochoristic
Q: Phylum Gnathostomulida
Answer:
- Uncertain classification
Interstitial
Turbellarian-like characteristics (acoelomate, ciliated epidermis, incomplete gut,
protonephridia, no specialized respiratory or circulatory systems)
Q: Phylum Micrognathozoa
Answer:
- Very tiny (0.14 mm)
Only females known
, Q: Phylum Nemertea
Answer:
- Ribbon worms
Rhynchocoel (fluid filled space that houses proboscis, properties of hydrostatic
skeleton, prey capture)
Turbellarian-like (veriform (worm-like), flattened, ciliated epidermis, eyes, paired
nerve system)
Not turbellarian-like (complete gut, circulatory system, larger)
Proboscis for feeding (inverted within head)
Burrowing
Q: Phylum Mollusca
Answer:
- 8 classes
Gas exchange across filaments (countercurrent gas exchange) (all except
cephalopods)
Q: Mollusca anatomy
Answer:
- Mantle (dorsal tissue that secretes shell, gas exchange)
Radula (tiny teeth used for scraping food particles)
Foot (muscular, locomotion, grasping, burrowing, or feeding)
Coelomate (not used as hydrostatic skeleton)
Shell
Q: Layers of shell
Answer:
- Periostracum (outermost, organic layer with chitin, protection, communication
through colours and chemicals)
Prismatic (middle, inorganic, structural, locomotion, protection)
Nacreous (innermost, inorganic, muscle attachments)
Q: Class Polyplacophora
Answer:
- "Many plate bearer", chitons
Solutions | Latest 2026 Update
Q: Gnathifera
Answer:
- Complex pharyngeal jaws
Non-molting
Can't regenerate lost body parts
No asexual reproduction through fission
Non-living out covering
Q: Phylum Aschelminthes
Answer:
- Roundworms
Pseudocoelomate
Eutely (number of cells fixed at adulthood, cells increase in size for growth)
Q: Phylum Rotifera
Answer:
- "Wheel-bearing"
Mastax and trophi (jaw)
"Toes" with adhesive gland
Q: Corona (two lobes covered in cilia)
Answer:
creates water current, brings in food particles, respiration, locomotion
Protonephridia
Syncytial epidermis (support and protection)
Gonochoristic
Looping (adhesive toes, mouth as suction cup)
Cryptobiosis (withstand harsh conditions)
Q: Class Seisonidea
Answer:
- Ectoparasitic on crustaceans
,Reduced corona
Q: Class Bdelloidea
Answer:
- Males have never been observed
Reproduce through parthogenesis (diploid egg develops directly into females)
0 0 Free living and motile
Q: Class Monogonata
Answer:
- Free living and motile (some sessile)
Facultative parthenogenesis (can alternate with sexual reproduction)
Q: Phylum Acanthocephala
Answer:
- Spiny head
Endoparasites (vertebrates = definitive, crustacean = intermediate)
Ligament sacs
Proboscis with hooks
Syncytial epidermis
Spiny proboscis (functions like scolex)
Body regions = proboscis, neck, trunk
Gonochoristic
Q: Phylum Gnathostomulida
Answer:
- Uncertain classification
Interstitial
Turbellarian-like characteristics (acoelomate, ciliated epidermis, incomplete gut,
protonephridia, no specialized respiratory or circulatory systems)
Q: Phylum Micrognathozoa
Answer:
- Very tiny (0.14 mm)
Only females known
, Q: Phylum Nemertea
Answer:
- Ribbon worms
Rhynchocoel (fluid filled space that houses proboscis, properties of hydrostatic
skeleton, prey capture)
Turbellarian-like (veriform (worm-like), flattened, ciliated epidermis, eyes, paired
nerve system)
Not turbellarian-like (complete gut, circulatory system, larger)
Proboscis for feeding (inverted within head)
Burrowing
Q: Phylum Mollusca
Answer:
- 8 classes
Gas exchange across filaments (countercurrent gas exchange) (all except
cephalopods)
Q: Mollusca anatomy
Answer:
- Mantle (dorsal tissue that secretes shell, gas exchange)
Radula (tiny teeth used for scraping food particles)
Foot (muscular, locomotion, grasping, burrowing, or feeding)
Coelomate (not used as hydrostatic skeleton)
Shell
Q: Layers of shell
Answer:
- Periostracum (outermost, organic layer with chitin, protection, communication
through colours and chemicals)
Prismatic (middle, inorganic, structural, locomotion, protection)
Nacreous (innermost, inorganic, muscle attachments)
Q: Class Polyplacophora
Answer:
- "Many plate bearer", chitons
