Invertebrates - Phy;um Platyhelminthes: Flatworms

body plan

bilateral

tissue

triploblastic, acoelomate

acoelomate

no body cavity

Protostome or Deuterostome?

protostome (but incomplete digest

cephalization

simple, nerve tissues and sensory organs in head

digestive system

- mouth is also anus
— ingested food goes into rudimentary digestive system
— food is digested extracellularly then absorbed into cells of gut
— waste products are released through pores in the epidermis

excretory system

-- a network of tubules running along the periphery of the animal
— have flame cells with cilia that propel waste fluid out of the body through pores

nervous system

two nerve cord running the length of the body, two cerebral ganglia for sensing light and chemicals

how is gas exchanged in platyhelminthes

through the epidermis

how are nutrients transported in platyhelminthes

distributed through gap junctions

what systems do platyhelminthes lack?

circulatory and respiratory

reproduction type

monoecious, internal fertilization where eggs are produced; most sexually but some asexual

platyhelminthes have what kind of digestive system

incomplete

rudimentary digestive system

food digested in intestines