Bio 242 Exam Questions with Complete
Answers
Platythelminthes Marine falt worms. bilateral symmetry, 3 tissue layers (mesoderm),
protosome development. Parasites such as tape worms and trematodes. Acelomates
Planarians A free-living flatworm found in unpolluted freshwater ponds and streams. Feed on
smaller animals or dead animals. Have centralized nervous systems. Hermaphrodites
Trematodes Diverse hosts, and complex life cycle with alternating sexual and asexual stages.
Require intermediate hosts.
Tape worms Live in guts of vertebrate hosts. Scolex main part of body contain suckers and
hooks. Prolottides contain the sex organs and produce eggs. Transported through fleas or
domestic animals.
Molluscs A soft-bodied animal characterized by a muscular foot, mantle, mantle cavity, and
radula; includes gastropods (snails and slugs), bivalves (clams, oysters, and scallops), and
cephalopods (squids and octopuses). Coelom and hemocoel. Have visceral mass.
Gastropods snails and slugs. Mantle cavity becomes lungs in terrestrial. Most marine some
freshwater. Mostly herbivores.
, Bivalves mollusks that have two shells held together by hinges and strong muscles. Aquatic.
Two shells with adductor muscles. Scallops mobile. Fresh water threatened.
Cephalopods A member of a group of molluscs that include squids and octopus
octopuses and squids Release ink, controlled chromataphores allowing them to change color
in seconds, 8 arms (squid have extra two tentacles, with hooked suckers), Giant and Colossal
squid largest invertebrates on earth up to 60ft long. Octopuses venomous and have well
developed brain.
Annelids A segmented worm which include earthworms, polychaetes, and leeches. Live in
marine, freshwater, and damp environments.
Errantia Free-living or burrowing, benthic polychaetes or tube worms. all segments similar.
Have parapodia and setae.
Sedentaria
worm castings when a worm makes a burrowed hole through soil because it eats it may also
drag fallen leaves down into it.
Ecdysozoa Supergroup of protostomes; characterized by periodic molting of their
exoskeleton (cuticle). Include the roundworms and arthropods.
Answers
Platythelminthes Marine falt worms. bilateral symmetry, 3 tissue layers (mesoderm),
protosome development. Parasites such as tape worms and trematodes. Acelomates
Planarians A free-living flatworm found in unpolluted freshwater ponds and streams. Feed on
smaller animals or dead animals. Have centralized nervous systems. Hermaphrodites
Trematodes Diverse hosts, and complex life cycle with alternating sexual and asexual stages.
Require intermediate hosts.
Tape worms Live in guts of vertebrate hosts. Scolex main part of body contain suckers and
hooks. Prolottides contain the sex organs and produce eggs. Transported through fleas or
domestic animals.
Molluscs A soft-bodied animal characterized by a muscular foot, mantle, mantle cavity, and
radula; includes gastropods (snails and slugs), bivalves (clams, oysters, and scallops), and
cephalopods (squids and octopuses). Coelom and hemocoel. Have visceral mass.
Gastropods snails and slugs. Mantle cavity becomes lungs in terrestrial. Most marine some
freshwater. Mostly herbivores.
, Bivalves mollusks that have two shells held together by hinges and strong muscles. Aquatic.
Two shells with adductor muscles. Scallops mobile. Fresh water threatened.
Cephalopods A member of a group of molluscs that include squids and octopus
octopuses and squids Release ink, controlled chromataphores allowing them to change color
in seconds, 8 arms (squid have extra two tentacles, with hooked suckers), Giant and Colossal
squid largest invertebrates on earth up to 60ft long. Octopuses venomous and have well
developed brain.
Annelids A segmented worm which include earthworms, polychaetes, and leeches. Live in
marine, freshwater, and damp environments.
Errantia Free-living or burrowing, benthic polychaetes or tube worms. all segments similar.
Have parapodia and setae.
Sedentaria
worm castings when a worm makes a burrowed hole through soil because it eats it may also
drag fallen leaves down into it.
Ecdysozoa Supergroup of protostomes; characterized by periodic molting of their
exoskeleton (cuticle). Include the roundworms and arthropods.
