Advanced Invertebrates
Circulation
Support, Growth & Movement
Nervous Systems (cont’d)
Circulation
• mollusks– bivalves and gastropods – open w/ hemolymph &
heart– cephalopods – closed w/ heart
• annelids – closed w/ aortic arches• arthropods
– crustaceans – open– chelicerates – open– uniramians – open w/ heart & aorta
• echinoderms – cellular diffusion
Support, Growth & Movement
• mollusks– Gastropods
• have 1 shell• exhibit torsion• move w/ wavelike contractions
of foot
– Bivalves• have 2 shells• move with “hatchet foot”
extruded from body
Support, Growth & Movement
• mollusks– Cephalopods
• jet propulsion
• stabilize with fins sometimes
• can crawl• very malleable body
Support, Growth & Movement
• annelida– longitudinal
muscles – circular muscles– parapodia –
stumpy leg-like appendages
– setae – bristle like hairs
Support, Growth & Movement
• arthropods– molt to grow larger – shed exoskeleton– unprotected until new exoskeleton hardens
– many muscles– jointed appendages allow full range of motion
Support, Growth & Movement
• echinodermata– metamorphosis from bilaterally symmetrical
larvae called bipinnaria to radially symmetrical adult
– movement with a water vascular system
Neural Control & Sensory Organs
• annelids– chain of ganglia– ventral nerve cord connects ganglia in each
segment
– setae
Neural Control & Sensory Organs
• arthropods– crustaceans
• paired ganglia• pair of branched antenna & pair of antennules, sensory hairs• compound eyes on stalks
– chelicerates• brain• simple eyes: usually three or more
– uniramians• brain & ventral nerve cord• paired ganglia in each segment• antenna & sensory hairs• simple & compound eyes• tympanum: sound sensing
Neural Control & Sensory Organs
• echinodermata – nerve ring– radial nerves