Download Marine Worms

Marine
Worms
Hawaiian Lined Fireworm
Platyhelminthes
Nemertea
Nematoda
Annelida
Featherduster Worm
Introduction
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Invertebrates
Bilateral symmetry
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Left & right sides
Tenia solium, a cestode
showing simple cephalization
Cephalization = concentration of nerve & sensory
tissue in the “head” region
One-way digestive system
Some worms are parasites, others are free-living
Flatworms
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Phylum Platyhelminthes
20,000 species - Some are parasitic, but
most are free-living
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Move using a layer of muscles
Simple digestive system – cavity
No true respiratory or circulatory
systems
Examples:
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Tubellaria (Planarians) = brightly colored
reef worms
Cestoda (Tapeworms)
Trematoda (Flukes)
Fluke
Tapeworm
Planarian
Ribbon Worms
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Phylum Nemertea
Soft, unsegmented body
One-way digestive system
Many grow up to 100 ft long
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Lineus longissimus = longest
known creature ~ 200ft long
Proboscis
Used to capture prey
 Secretes toxins
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Roundworms
juvenile nematode
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Large adult female
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Phylum Nematoda
12,000 known species
Round body
One-way digestive system
Range in size from 0.3 mm
to over 8 meters
Most are free-living in water,
soil, & soft sediment
 Many are parasites
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Juvenile nematodes emerging
from a beet armyworm pupa
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Segmented Worms
Phylum Annelida
Segments are nearly identical
Class Polychaeta (5,400 species)
Largest & most diverse class of annelids
 Range in length from 1 – 15 cm
 Burrow into substrate, live in tubes or swim freely
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Earthworms, leeches, and polychaete worms
Polychaetes
Tubeworm – secretes and
lives in tube
Fireworm – contains poisons
in bristles
Featherduster worm
Video notes: Biology of Annelids
Introduction (2)
 Polychaetes (7)
 Oligochaetes (5)
 Class Hirudineo (3)
 Annelid Evolution (3)
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