1. Worm Phyla
Phylum Platyhelminthes
Phylum Nematoda
Phylum Annelida

2. Phylum Annelida The name means “little rings” earthworms and leeches
segmented bodies (internal and external)
Bilateral symmetry
Systems – nervous, digestive (gut, mouth, anus), closed circulatory
Sexual Reproduction
Hydrostatic skeleton
fluid-filled cavity (coelem) surrounded by muscles
Cephalopods (have a head)
Concentrated with nerve cells and sensory structures
Worm Video

3. Phylum Platyhelminthes
Flatworms
un-segmented (no rings) and appear flat
most no more than a few millimeters thick.
have tissues and internal organs systems
bilateral symmetry,
cephalization (which means they have a head!)
Flatworm video

4. Flatworm Characteristics
single digestive opening (Mouth/Anus)-food enters and undigested waste leaves.
Because they are so thin, most flatworms do not need a circulatory system to transport materials, but use diffusion.
Respiration also occurs through diffusion
They move to obtain food and escape predators.
They can be both carnivorous or parasitic (this tapeworm lives inside the human intestines).

5. Phylum Nematoda Roundworms unsegmented worms
microscopic or a large as a meter in length!
Most roundworms are free living and are found in the soil, the sea floor, or water.
Others are parasites that live in plants and animals.