How are worms different ALL WORMS are INVERTEBRATES

How are worms different?

ALL WORMS are: INVERTEBRATES (no backbone) PROTOSTOMES (blastopore mouth) COELOM TYPES: Flatworms = acoelomates Round worms = Pseudocoelomates Segmented worms = coelomates

FLAT WORMS (PLATYHELMINTHES) TAPEWORMS PLANARIA FLUKES

FLATWORMS Planaria (Cross-eyed worm)

DIGESTIVE/CIRCULATORY SYSTEMS One big cavity for digestion and circulation = Gastrovascular cavity Only one opening- in and out through mouth

MOUTH in middle on VENTRAL SURFACE

NERVOUS SYSTEM CEPHALIZATIONCEREBRAL GANGLIA with 2 VENTRAL NERVE CORDS

REGENERATION (Ability to regrow lost body parts)

REPRODUCTION HERMAPHRODITES- Sexual reproduction with partner Can also use REGENERATION for ASEXUAL reproduction

FLATWORMS PLANARIA • Free living • Digestive cavity with one opening/mouth in middle of body • Open circulatory system (shared Gastrovascular cavity) • Flame cells for excreting nitrogen waste and excess water • Cephalization-Cerebral ganglia with 2 nerve cords • Hermaphrodites with sexual reproduction (asexual reproduction using regeneration) • Eye spots sense light and dark • No protective covering

FLATWORMS FLUKES

DIGESTIVE/CIRCULATORY, NERVOUS, & EXCRETORY Similar to Planaria

MOUTH at anterior end SUCKERS (anterior and ventral) help it hold on and suck blood

REPRODUCTION COMPLICATED LIFE CYCLES need 2 hosts to complete life cycle EX: BLOOD FLUKE Adult-human larva-snails Most HERMAPHRODITES- Sexual reproduction with partner

FLATWORMS • • • FLUKES Flattened leaf shape Digestive cavity with one opening /mouth at anterior end Open circulatory system (Gastrovascular cavity) Flame cells for excreting nitrogen waste and excess water Cephalization -Cerebral ganglia with 2 nerve cords Hermaphrodites with sexual reproduction NO Eyes Parasitic with 2 suckers (anterior & ventral) for attaching to host Requires 2 hosts to complete life cycle TEGUMENT for protection from host

FLATWORMS TAPEWORMS Dog tapeworm

EXCRETORY & NERVOUS similar to other flatworms NO DIGESTIVE SYSTEM Absorbs nutrients through its tegument

SCOLEX with hooks and suckers at anterior end to help worm attach and hold on

REPRODUCTION COMPLICATED LIFE CYCLES need 2 hosts to complete life cycle EX: BEEF TAPEWORM Adult-human larva-cow HERMAPHRODITES- Proglottids exchange sperm between different worms or within same worm

REPRODUCTION Adults produce hermaphroditic reproductive segments containing eggs that are released in feces called PROGLOTTIDS

FLATWORMS TAPEWORMS • NO digestive system/nutrients absorbed through tegument • Flame cells for excreting nitrogen waste and excess water • Cerebral ganglia with 2 nerve cords • Parasitic with hooks & suckers (scolex) for attachment in host • Tegument for protection from host immune system and digestive juices • Hermaphrodites with sexual reproduction Use PROGLOTTIDS to reproduce • No Eyes

ROUND WORMS Ex: Ascaris • Digestive system - Complex with 2 openings • Nephridia for excreting nitrogen waste and excess water • Cephalization-Cerebral ganglia with 2 nerve cords • Sexual reproduction with separate sexes- male and female • No eyes spots • CUTICLE- for protection from host digestive juices and immune system • Most are parasitic

SEGMENTED WORMS Earthworms & Leeches • Cephalizationcerebral ganglia with 1 ventral nerve cord • Closed circulatory system • Nephridia excrete nitrogen waste and regulate water • Complex digestive system with 2 openings • CUTICLE- for protection • Hermaphrodites- Sexual reproduction with a partner • Most free living/Leeches only parasitic group