1. Tapeworms
1.1. In other ripe proglottids, eggs made by ovaries can be seen
1.1.1. Tapeworms are hermaphrodites that fertilize their own eggs
1.1.1.1. Each proglottid produces hundreds of eggs. These eggs pass out of the host’s body with wastes.
1.2. Mature proglottids have an external genital pore. The sperm duct leads from the genital pore
1.2.1. The testes, which make sperm, are small round bodies in the proglottids
1.3. Don't have a digestive system since they feed on food digested by their host.
1.4. Tapeworms continue to grow and add proglottids and may reach 40 feet long
1.5. The head or scolex is located at the anterior end and has both hooks and suckers for attachment to the inside of the host
1.6. Don't have true body segments, but their body does have reproductive sections called proglottids
1.7. Parasitic flatworms that live inside the intestines of their hosts
2. Flukes
2.1. Adult flukes live inside the liver of cattle and lay eggs
2.1.1. These eggs pass out with wastes and the eggs hatch into larva in the water
2.1.1.1. The larva enters its next host, the snail
2.1.1.1.1. Eventually, the young flukes leave the body of the snail and attach to grasses growing along the water’s edge
2.1.1.1.2. It goes through several developmental changes in this intermediate host
2.2. Flukes may live in more than one host during their life cycle
2.3. They have only an anterior sucker for host attachment
2.4. Another type of parasitic flatworm
3. 3 body layers:
3.1. the middle mesoderm
3.2. the inner endoderm
3.3. the outer ectoderm
4. Don't have a fluid-filled body cavity or coelom. Instead, the body of flatworms is solid (filled with cells); therefore, they are said to be acoelomate animals.
4.1. Flatworms have bilateral symmetry. Bilateral symmetry means that the animal can be divided in one plane into two, mirror images (a right and left side.)
4.2. Animals with bilateral symmetry have dorsal (upper)and ventral (lower) sides, as well as anterior (forward or head end) and posterior (tail or hind) ends
5. flattened dorsoventrally (top to bottom)
6. includes the freshwater, free-living planarian and the parasitic fluke and tapeworm
7. in the phylum Platyhelminthes
8. Planarian
8.1. Genus as Dugesia, lives in freshwater and is a scavenger on decaying material (detritus). It will also feed on protists in the water
8.2. Like all flatworms, it has only one opening into its body, the mouth. The mouth is located at the end of a tube that can be extended called the pharynx
8.2.1. The mouth opens into the gastrovascular cavity of the hydra where digestion takes place. Wastes exit the planarian through the mouth
8.3. The anterior or head end of flatworms has a concentration of sensory structures. This is known as cephalization
8.3.1. Two light sensitive eyespots are located at this end
8.4. Internally, the planarian has a simple brain at the anterior end and two long, nerve cords extending from this toward the posterior of the worm
8.4.1. The intestine extends most of the length of the body and has side pouches to increase the surface area for absorption
8.5. Planarians have a great ability to regenerate (regrow lost body parts)
8.6. Planarians are hermaphrodites containing both testes to make sperm and ovaries to produce eggs
8.6.1. Planarians can also reproduce asexually by fragmentation (splitting into pieces)
8.6.2. Don't fertilize their own eggs however.