Invertebrates: Platyhelminthes and Annelida/Nematoda

Protosomes

-blastopore forms mouth
-spiral cleavage
-determine cell fate

Phylum Platyhelminthes

-flatworms 
-triploblastic
-bilateral symmetry
-cephalization
-acoelomate worms (no coelomate)
-dorso-ventral flattening
- incomplete digestive tract --> food and waste go through same opening

Class Turbellaria

-freeliving
-carnivores
-cilia
ex. planaria

Class Trematoda

-parasitic
-suckers & hooks
-forked digestive tract
ex. flukes
(clonorchis) liver fluke or (schistosoma) blood fluke

Schitosomiasis

-snail intermediate host 
-infect blood vessels
-anemia
-liver enlargement
-brain & bladder damage
- haematuria (blood in urine)

Class Cestoda

-no digestive tract 
- specialized attachment=scolex
-proglottids=reproductive segments 
ex. tapeworms (tpw), beef,pork and dog tpw

Phylum Annelida

-bilateral
-segmented worms
-setae (bristles)
-2 sets of muscle
longitudinal-->side to side 
circular-->scrunch up
-coelom
-closed circulation
-*have serial homolgy:segmentation*

Class Errantia

-many setae
-polychaete
-parapodia=appendages (on each segment)
-marine
-active carnivore (errant)
ex. lugworm, bristle or fireworm (hermodice)

Class Sedentaria

-few setae,terrestrial or freshwater, ex. earthworm
OR
-marine tubeworms,feather worm
-suspension feeder
-sentary tube dwelling parchmanet worm
-ice cream worm: tube made w/ mucus and sand grains
-mucus feeding bag

Fan worm (Class Sedentaria)

-suspension feeding

-tube composed of glandular secretions & sand grains

Class Hirudinidae

-leeches, most freshwater, no setae, oral suckers
*not parasite more so predators*
-medicinal leech use, dates back to the 15th century 
-used for anaesthetic, eat to 6 to 8 times their body weight --> used for tissue graft, reducing swelling