2. Flatworms
Phylum: Platyhelminthes

3. Key facts: 1. have bilateral symmetry
2. have tissues organized into organs
3. have no respiratory or circulatory system

4. 4. The branches of the digestive tract reach tissue directly
5. Sexual and asexual reproduction
Intestine nerve cord excretory system reproductive system

5. Tapeworm: parasite - can be 40ft long – absorbs food through skin – each segment is a complete reproductive unit – can infect humans

6. Roundworm
Phylum: Nematoda

7. Key facts:
1. Has a body cavity

8. 2. Most are parasitic (150 species, including
hookworm, heartworm, etc are parasitic to
plants and animals). Lay eggs in a host
3. Has simple circulatory system and a digestive
tract with a mouth at one end and can secrete
waste at the other.
4. Most are microscopic or only a few mm long