Ch 6 Echinoderms , Mollusk and Chordates

What Mollusks in glass Gastropods are

• single shelled mollusk , snails, and whelks

• oysters, clams and scallops

• octopus, squid, and clams

• all of the above

Organisms in phylum Mollusca include ( select all that apply)

• Sea slugs

• snails

• squid

• stingrays

Sand dollars and sea urchins are in class _____, which is characterized by _____and ____

• Echinoidea, no arms, ball or disk shape

• Holothuroidea, elongated body, tentacles around the mouth

• Ophiuroidea, long thin legs, single organ set in central disk

• Crinoidea, upward-facing mouth, long feather-like arms

_____ may possibly be the longest animal in the world.

• the blue whale

• a siphonophore.

• Lineus longissimus.

• none of the above

Members of phylum Echinodermata are similar to chordates because

• their larvae are bilaterally symmetrical.

• they have decentralized nervous systems.

• most species have no head.

• all of the above

Brittle stars are in class _____, which is characterized by _____and _____.

• Echinoidea, no arms, ball or disk shape

• Holothuroidea, elongated body, tentacles around the mouth

• Ophiuroidea, long thin legs, single organ set in central disk

• Asteroidea, five arms with equal share of organs, downward-facing mouth

Organisms in subphylum Cephalochordata include 25 species of _____, which are significant because they resemble _____.

• lancelets, cephalopods

• octopuses, vertebrates

• cephalopods, vertebrates

• lancelets, vertebrates

Mollusks in Class Bivalvia

• have two shells.

• lack a “head.”

• do not have a radula.

• all of the above

Sea lilies and feather stars are in class _____, which is characterized by _____ and _____

• Echinoidea, no arms, ball or disk shape

• Holothuroidea, elongated body, tentacles around the mouth

• Ophiuroidea, long thin legs, single organ set in central disk

• Crinoidea, upward-facing mouth, long feather-like arms

Organisms in phylum Echinodermata are distinguished by characteristics including (select all that apply)

• radially symmetrical bodies.

• bilaterally symmetrical larvae.

• five-segment bodies.

• tube feet.