How are worms different?

3 KINDS OF WORMS

Some free living and some parasites in every group

ALL WORMS ARE:INVERTEBRATES no backbone

PROTOSTOMESblastopore becomes MOUTH

COELOMS: Flatworms = acoelomates

Round worms = Pseudocoelomates

Segmented worms = Eucoelomates

FLATWORMSPLANARIA

TAPEWORMS

FLUKES

FLATWORMSPlanaria

(Cross-eyed worms)

RESPIRATORY Breathe through their skin

DIGESTIVE/CIRCULATORY Gastrovascular cavity with 1 opening

NERVOUS 2 cerebral ganglia/2 nerve cords

EXCRETORY Flame cells remove nitrogen waste

through skin

MOUTH in middle on VENTRAL SURFACE

REPRODUCTIONSEXUAL- HERMAPHRODITES

but trade sperm with a partner

ASEXUAL- can use regeneration to grow a new organism

from parts

FLATWORMSPLANARIA

• 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

(Can also do asexual reproduction using regeneration)• Eye spots sense light and dark• NO tegument or cuticle

FLATWORMSFLUKES

PARASITIC

Covered by TEGUMENT(made of fused cells) for protection from host immune system

MOUTH at anterior endNOT middle of body

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

DIGESTIVE/CIRCULATORY

shared GASTROVASCULAR cavity similar to Planaria

NERVOUS CEPHALIZATION Cerebral ganglia with 2 nerve cords

No eyes

EXCRETORY Flame cells remove nitrogen waste &

regulate water

FLUKESREPRODUCTIVE Most hermaphrodites Few have separate sexes

(EX: Blood fluke-Schistosoma)

Complicated life cycle with 2 hostsEX: Blood fluke-Schistosoma

Adults live in human Larva live in snails

FLATWORMSFLUKES

• Gastrovascular cavity with one opening /mouth at anterior end• Open circulatory system (shared with Gastrovascular cavity)• Flame cells for excreting nitrogen waste

and excess water• Breathe through skin• Cephalization –2 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 immune system

FLATWORMSTAPEWORMS

DIGESTIVENo mouth or digestive organs Absorbs nutrients through its tegument

EXCRETORYFlame cells remove nitrogen waste

NERVOUS2 cerebral ganglia/ 2 nerve cordsCephalizationNo eyes

TEGUMENT (made of fused cells) protects from host digestive enzymes and immune system

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

TAPEWORMSREPRODUCTIVE• Hermaphrodites-

can fertilize self or trade sperm with other worms

• Grow by adding PROGLOTTIDSwhich contain both male and female reproductive organs

30 foot worm can have 2000 proglottids

REPRODUCTIONCOMPLICATED LIFE CYCLES

need 2 hosts to complete life cycle

EX: BEEF TAPEWORM Adults feed and reproduce in humans

larva make cysts in cow

FLATWORMSTAPEWORMS

• NO MOUTH or ANUS or digestive systemnutrients absorbed through tegument

• Breathe through skin• Flame cells for excreting nitrogen waste• 2 Cerebral ganglia with 2 nerve cords

No Eyes• 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 Complicated life cycle with 2 hosts

3 KINDS OF WORMS

ALL FLAT WORMSDigestive system with less than 2 openings (one or none)• Open circulatory system • Breathe through skin• FLAME CELLS for excreting nitrogen waste and

excess water• Cephalization –2 Cerebral ganglia with 2 nerve cords• Most HERMAPHRODITES with sexual reproduction• If parasites need 2 different hosts to complete life cycle• NO CUTICLE for protection

(Has TEGUMENT or NOTHING)

ROUND WORMSAscaris

TrichinellaHookwormsPinworms

Filarial wormsSoy bean cyst

DIGESTIVEComplete disgestive system with MOUTH and ANUS

Parasitic ones have biting mouth partsto hang onto host

NERVOUS CEPHALIZATION Cerebral ganglia with 2 nerve cords

No eyes

EXCRETORY Nephridia remove nitrogen waste

INTEGUMENTARY Covered with non-cellular CUTICLE for

protection

RESPIRATORY exchange gases through skin

CIRCULATORY Open circulation like flatworms

REPRODUCTIVE SEPARATE SEXES (males & females)

Life cycle does NOT require 2 different hosts

ROUND WORMS• Complete digestive system with 2 openings• Open circulatory system • Breathe through skin• Nephridia for excreting nitrogen waste and excess water• Cephalization –2 Cerebral ganglia with 2 nerve cords/ NO Eyes• SEPARATE SEXES with sexual reproduction• Parasites have teeth but NO suckers for attaching to host• DO NOT Require 2 different hosts to complete life cycle• CUTICLE for protection from host immune system

SEGMENTED WORMSEarthworms Leeches

NERVOUS CEPHALIZATION Cerebral ganglia with 1 nerve cord

No eyes

EXCRETORY Nephridia remove nitrogen waste

INTEGUMENTARY Covered with non-cellular CUTICLE for

protection

RESPIRATORY exchange gases through skin

SEGMENTED WORMSCIRCULATORY CLOSED circulation (blood in vessels)

REPRODUCTIVE HERMAPHRODITES- exchange sperm with partner

SEGMENTED WORMS• Complete digestive system with 2 openings• CLOSED circulatory system • Breathe through skin• Nephridia for excreting nitrogen waste • Cephalization –2 Cerebral ganglia with 1 nerve cord

NO Eyes• HERMAPHRODITES with sexual reproduction• Parasites have suckers for attaching to host• DO NOT Require 2 different hosts to complete life

cycle• CUTICLE for protection