1. Phylum Platyhelminthes
Flatworms
Flukes
Tapeworms
Phylum Platyhelminthes

2. Phylum Platyhelminthes

3. Phylum Platyhelminthes

4. Phylum Platyhelminthes

5. Phylum Platyhelminthes

6. Phylum Platyhelminthes
Flatworm Body Plans
Exhibit bilateral symmetry, acoelomate and………
Phylum Platyhelminthes

7. Phylum Platyhelminthes
Regeneration
Many species posses remarkable powers of regeneration and repair wounds
Phylum Platyhelminthes

8. Phylum Platyhelminthes
Planarians are capable of asexual reproduction via fission
Phylum Platyhelminthes

9. Phylum Platyhelminthes
Reproduction
Almost all are simultaneous hermaphrodites
Parasitic species (flukes and tapeworms) have complex lifecycles,
Phylum Platyhelminthes

10. Phylum Platyhelminthes
Nervous System
Free-living species usually have a well-developed sensory system
Parasites generally have less elaborate systems.
WHY?
Phylum Platyhelminthes

11. Phylum Platyhelminthes
Flatworms
Some species also have a protrusible pharynx that captures food and transfers it into the mouth
Can be carnivores or scavenge on dead animals and detritus
Phylum Platyhelminthes

12. Phylum Platyhelminthes
Tapeworms
Phylum Platyhelminthes

13. Phylum Platyhelminthes
Beef tapeworm
Phylum Platyhelminthes

14. Problems of a parasitic existence
Must reproduce within the definitive host
Must get fertilized eggs out of the host
Finding a new and appropriate host
Obtain entrance into the host
Locate the appropriate environment within the host
Maintain position within the host
Withstand an often anaerobic environment
Avoid digestion or attack by the hosts immune system
Avoid killing the host, at least until reproduction is completed
Phylum Platyhelminthes