Lec 4: mollusca, echinodermata, primitive chordata

Question 1

Phylum mollusca

Answer 1

Snails, clams octopuses, squids. Bilateral, triploblastic, coelomate , open gut, shell = CaCO2, foot (muscular structure) mantle (secretes shell for respiration) *radula (rasp like feeding structure (razor tongue) *trochophore larval form

Question 2

Class polyplacophora (phylum mollusca)

Answer 2

“chitons” 8 dorsal plates on back, made of CaCO3. found in tide pools in boundary layer (thin layer of water near rocks)

Question 3

Class gastropoda (phylum mollusca)

Answer 3

Snails, slugs. Some undergo torsion (twisting of body 180° relative to head) as adaptation for predation

Question 4

class bivalvia (phylum mollusca)

Answer 4

clams, oysters, scallops. Filter feeders, active pumping of water, *glochidia larvae (attach to fish gills, parasitic)

Question 5

class scaphopoda (phylum mollusca)

Answer 5

“tusk” shells, deep sea sediments

Question 6

Class cephalopoda (phylum mollusca)

Answer 6

Squid, octopus, cuttlefish, nautilus. Advanced sensory abilities, nervous system, camouflage. Octopus/squid can change skin texture, * chromatophores (pigment containing cells for camoflauge)

Question 7

Phylum Echinodermata

Answer 7

Sea stars, urchins, crinoids, sea cucumbers. Bilateral (larval form) triploblastic, coelomate, open gut, *water vascular system (hydraulic system for movement/feeding/respiration)

Question 8

class asteroidea (phylum echinodermata)

Answer 8

sea stars! *keystone predators (keeps mollusk population in check) can regenerate arms

Question 9

class ophiurdea (phylum echinodermata)

Answer 9

Brittle stars (scavengers) basket stars (suspension feeders) long slender arms that can be shed

Question 10

Class crinoidea (phylum echinodermata)

Answer 10

“feather star”/“sea lily” Deep sea suspension feeders. Have central stalk for attaching to substrates

Question 11

Class echinoidea (phylum echinodermata)

Answer 11

urchins, sand dollars, exoskeleton (“test”) Aristotle’s lantern (5 hard jaw like plates around mouth for food, sea urchins only)

Question 12

Phylum Chordata

Answer 12

Dorsal hollow nerve cord (dev into brain/spinal cord) notocord (rod that provides support, turns into spine) pharyngeal slits (openings in throat reg, become gills in fish or structure for ears/throat for land animals) muscular post anal tail

Question 13

Subphylum cephalochordata

Answer 13

“lancelets” (small fish-like marine animals that retain 4 chordata traits all life)

Question 14

Subphylum Urochordata

Answer 14

“tunicates” (sea squirts) expels water when disturbed

Question 15

Class holothuroidea (phylum echinodermata)

Answer 15

Sea cucumber. When threatened do invisceration (throw up 1/3 gut”) to distract predator, scavengers