unsegmemted worms in general Flashcards
how does the long, slender body shape of a worm match its lifestyle
easy to manouver through soil, or cells
whata re the characteristics of phylum platyhelminthes
flat, unsegmented, has beginning of nervous system, flame cells, three tissue layers, bilaterally symmetrical, ganglia, celomate, gastrovascular cavity
define accelomate
without body cavity
define bilaterally symmetrical
mirror image from anrerior to posterior
define cephilization
ganglion with sensor organs at anterior
why is diffusion a suitable method of transport in flatworms
they are thin, flat, and can move easily in and out easily
describe the digestive system of a free-living flatworm
single opening gastrovascular cavity, branched
what is the pharynx used for
sucking in food
how is a branched gastrovascular cavity advantageous to a flatworm
increased surface area for more diffusion
describe adaptaions of parasitic flatworms to their parasitic lifestyle
no pharynx cuticle complex reproduction system has a scolex loose gastrovascular cavity lost nervous system
what are flame cells
pick up ammonia and water for excretion
describe the nervous system of a flatworm, including ganglia and eyespot
ganglia= collection of nerves which stimulate muscle contractions eyespot= light sensitive, (ocelli)
how is the nervous system of a flatworm more complex than the sensory cells and nerve net of a cnidarian
flatworms: more structures, more detection censers, statocysts, chemo-receptors
define hermaphrodite
has both sex organs
delivers and accepts sperm
describe scolex
in place of sefflia (head)
gas hooks and suckers
