1. WORM PHYLA

2. I. PLATYHELMINTHES A. General Traits 1. Flatworms
2. Bilateral symmetry
3. Soft bodied
4. Invertebrates
5. Examples: Tapeworms, Flukes, Planarians

3. B. Anatomy 1. No respiratory organs – uses diffusion
2. No circulatory organs
3. Distinct brain & central nervous system
4. Specialized digestive
system
5. Protostome - mouth
6. Acoelomate

4. Flatworms - Acoelomates

5. C. Reproduction 1. Hermaphroditic
2. Complex lifecycles involving parasitism and host infestation.

6. D. Platyhelminthes Phylum Classes
1. Class Cestoda
Anterior end with hooks (SCOLEX)
Body Divided into segments
(PROGLOTTIDS)
No digestive tract
Nutrients absorbed through skin
Parasitic – humans and animals
Acoelomate
Protostome
Example: Tapeworm

7. TAPEWORMS

8. D. Phylum Platyhelminthes Classes
2. Class Turbellaria
3 000 species
Habitat: Aquatic (marine)
Parasitic/Commensalistic
Hermaphroditic
Acoelomate
Protostome
Pharynx
Example: Planarian

9. Planarians

10. D. Phylum Platyhelminthes Classes
3. Class Trematoda
1 000 Species
Hermaphroditic
Have Digestive System
All are Parasitic
Alternate between Intermediate And
Definite Host
Protostome
Acoelomate
Example: Flukes

11. FLUKES

12. II. Nematoda A. General Traits 1. Roundworms 2. Not segmented
3. Bilateral symmetry
4. Adapt to every ecological niche
5. Comprise 90% of life on sea floor
6. Mostly microscopic
7. Examples: Hookworm, Pinworms
8. Parasitic on humans and animals (infect as many as1 million people)

13. B. Anatomy 1. Parasitic 2. Complete digestive system
3. Deuterostome - anus
3. No respiratory
4. No circulatory system
5. Simple nervous system
a. main ventral nerve
b. smaller dorsal nerve cord
6. Simple sensory organs at ends
7. Pseudocoelomate

14. Round Worms - Pseudocoelomate

15. C. Reproduction 1. Sexual 2. Some Hermaphroditic
3. Males are smaller with bent tails.

16. D. Phylum Nematoda Classes
1. Class Adenophorea
Most Primitive of Round Worms
species worldwide
Pseudocoelomates
Size - microscopic to 3.25 ft
Habitat – wide variety worldwide
Some Parasitic
Hermaphroditic & Individual Sexes
Cycle carbon/ nitrogen an breakdown
organic material in the soil
Protostome and Deuterostome
Examples: Whipworm, Trichina

17. TRICHINA
WHIPWORMS

18. Almost exclusively terrestrial 8 000 species worldwide
D. Phylum Nematoda Classes
2. Class Secernentea
Almost exclusively terrestrial
8 000 species worldwide
Parasitic of plants and animals
Pseudocoelomates
Size – can reach up to 30 ft long
Hermaphroditic & Individual Sexes
Protostome and Deuterostome
Examples: Hookworm, Heartworm

19. HOOKWORM HEARTWORM

20. III. Annelida
A. General Traits
1. Segmented
2. Bilateral symmetry
3. Habitat: most wet areas
4. Size: 1 mm to 3 m
5. Example: Earthworm, leech

21. B. Anatomy 1. Invertebrates 2. Closed circulatory system
3. Protostome & Deuterostome
4. Digestive tract with a gut
5. Eucoeolmate
6. Has a nerve cord and ganglia
7. Photoreceptors (but not eyes)
8. Hard chitin body

22. Segmented Worms- Eucoelomate

23. C. Reproduction a. Hermaphroditic or have distinct sexes.
1. Asexual
a. Fission - posterior part of worm breaks off forming a clone
b. Regeneration
2. Sexual
a. Hermaphroditic or have distinct sexes.
b. Aquatic - external fertilization.
c. Terrestrial - hermaphrodites which exchange gametes

24. D. Phylum Annelida Classes
1. Class Oligochaeta
known species
Eucoelomate
Protostome and Deuterostome
Size: 1/32 in. to 10 ft
Habitat: Soil environments
Hermaphroditic that cross-fertilize
Setae – stiff, bristle hairs on ventral
Surface
Closed Circulatory System
Example: Earthworm

25. EARTHWORM

26. D. Phylum Annelida Classes 2. Class Polychaeta
8 000 known marine species
Eucoelomate
Numerous setae
Protostome and Deuterostome
Size: 1/8 in. to 9 ft
Habitat: Marine and Fresh water; mud
Errant Polychaetes – active crawlers/
swimmers
Sedentary Polychaetes – live in burrows
or tubes; some attached to rocks
Examples: lugworms, clam worms

27. LUGWORM
CLAM WORM

28. D. Phylum Annelida Classes
3. Class Hirudinea
500 species
Predacious parasitic worms
Eucoelomate
Hermaphroditic
Anterior and Posterior suckers
Protostome and Deuterostome
Size: ½ in. to 8 ft.
2 to 10 eyes (photoreceptor clusters)
Closed Circulatory System
Fixed number of body segments – 34
Examples: Leeches

29. LEECH