1. Nemertea
Ribbon Worms

2. Development Bilateral Symmetry Three Germ Layers
Acoelomate (coelom in proboscis)
Radial and Indeterminate body development

3. Characteristics Live in a Marine Environment Dioecious (2 sexes)
Nervous System and Brain
Closed Circulatory System
Proboscis apparatus
Complete digestive tract
Carnivorous

4. Examples and Stories Lineus longissimus 30M long and a few mm wide
Reports of 60M
Basiodiscus mexicanus (at right)
Archisymplectes (only fossilized Nemertean)
Gorgonorhynchus repens (50mm long)

5. Lophophorate

6. Development Bilateral Acoelomate Three Germ Layers
Radial division during development

7. Characteristics
A lophophore is a band of cilliated tentacles surrounding the mouth
Lophophore are retractable into coelom like space

8. Platyhelminthes
By: Ben, Matt, and Haram

9. Characteristics Flatworms have bilateral symmetry.
They have no true body cavity except for the gut, and are classified as acoelmates.
Their organ systems are formed of ectoderm, endoderm, and mesoderm.

10. Schistosoma Life Cycle
Parasitic flatworms cause schistosoma in humans. -Infection occurs when cercariae penetrate the skin while in the water. -The cercaria loses its tail becoming a schistosomule which moves through various tissues to the veins. -Adults mature in the in the veins surrounding the intestines or bladder, depending on the species. -Females release eggs which move from the veins to the lumen of the intestine or the bladder. The eggs are then passed from the body in the feces or urine.

11. Trichinella Life Cycle

12. More Characteristics
Flatworms move by waving hair on their skin to propel themselves forward.
They also move by contracting their muscles.
Flatworm reproduction is hermaphroditic- each individual produces eggs and sperm.
When two flatworms mate, they exchange sperm so both become fertilized.

13. Specialized Tissues Flatworms have :
A sac body plan, meaning they have one opening that functions as both a mouth and an anus.
A pharynx, which extends form the underside of the flatworm and sucks up food through the mouth
Flame cells that are used for excretion.
Amazing regeneration capabilities.

14. Specialized Features
Cephalization (consists of 2 brains called ganglia and nerve cords arranged in a ladder-like configuration).
Gastrovascular cavity functions similarly to that of Cnidaria
Planarians, in Class Turbellaria, have eyespots that determines the presence and intensity of light.
The head (scolex) of the flatworms have hooks and suckers which function as an anchor.

15. Different Types of Flatworms
Free-living carnivorous planarians
Parasitic flukes that feed off the blood of other animals
Parasitic tapeworms that live inside the digestive tracts of other animals.

16. Examples of Flatworms Turbellaria (free-living) Planaria
Monogenea (parasitic)

17. More Examples
Cestoda : parasitic tapeworms
Digenea

18. Nematoda and Rotifera
Round worms

19. Symmetry
They have bilateral symmetry, and radial symmetry 19

20. Anatomy
Nematoda
Rotifera

21. Some Examples of Life Cycles

22. Specialized Tissues and Coelom
They have a simple nervous system that includes a main ventral nerve cord and a smaller dorsal nerve cord
They use diffusion to breathe
They don’t have an circulatory system so the fluid in their body moves nutrients around
They are the simplest group to have an complete digestive system
They also have a three layer cuticle to keep the body from drying out
Nematoda and Rotifera are Pseudocoelomates. This is when the body cavity is derived from the mesoderm. The tissues are only loosely bound so it is not as organized as an coelomate

23. Movement and Reproduction
They use hydrostatic skeleton which change liquid pressure in the body changing the bodies shape causing movement.
They also use longitudinal muscles to move their bodies side to side
Parthenogenesis is when the female can have a growth that separates into an offspring
They also can reproduce sexually

24. Examples of Roundworms
Whip worm
C. elegans

25. African spiral nematode
psammomermis
BANANA NEMATODE

26. Interesting facts
They are a major cause important diseases of plants, animals, and humans.
Diseases including filariasis, ascariasis, and trichinosis
Some live in food products such as beer and vinegar.