1. Flatworms/Roundworms Phylum Platyhelminthes Phylum Platyhelminthes platy-flat, helminth-worm platy-flat, helminth-worm three classes three classes 1. Class Turbellaria 2. Class Cestoda 3. Class Trematoda Bilateral symmetry Bilateral symmetry Non-segmented Non-segmented no respiratory or circulatory systems: depend on diffusion to transport nutrients. no respiratory or circulatory systems: depend on diffusion to transport nutrients. Sense receptors and nerves found at the anterior end Sense receptors and nerves found at the anterior end Free living or parasitic Free living or parasitic Found n rivers, lakes, and streams Found n rivers, lakes, and streams

2. Class Turbellaria: Flatworms a. free living b. posterior end tapers, anterior end is spade-shaped c. movement 1. swimming: muscle cells controlled by nervous system allow to twist and turn d. Feeding 1. scavengers 2. feed on protozoans 3. in the middle of their body, they have a small opening called a mouth. A muscular tube called a pharynx, located behind the mouth extends out of the mouth and sucks in the food. the mouth extends out of the mouth and sucks in the food. The food is passed into the intestine. Nutrients are absorbed by the intestinal wall through diffusion. Any waste or by the intestinal wall through diffusion. Any waste or undigested food are excreted through the pharynx and out undigested food are excreted through the pharynx and out through the mouth. through the mouth. 4. Flame cells: located on the ends of the branches of the 4. Flame cells: located on the ends of the branches of the intestines. Excess water are excreted through these cells. intestines. Excess water are excreted through these cells.

3. e. Nervous control 1. Eyespots: located on the anterior end of the body. Sense light 2. Ganglia: a cluster of nerve cells located on the anterior end of the body. Extending from the ganglia are two cords running the length of the body, Sense: touch, taste, and smell f. Reproduction 1. Sexual: Hermaphrodites a. no self-fertilization b. fertilize each other at the same time: worms join, one worm delivers sperm to another while receiving one worm delivers sperm to another while receiving sperm from its partner at the same time. sperm from its partner at the same time. 2. Asexual a. Regeneration. They attach themselves and stretch until they split in half. Each half regenerates. until they split in half. Each half regenerates.

4. g. Basic Structure: 1. gastrovascular cavity2. pharynx 3. mouth4. ganglia 5. Flame Cells6. Two nerve cords 7. eyespots8. anterior 9. posterior10. Intestines http://dragon.seowon.ac.kr/~bioedu/bio/ohp/t-162.jpg

5. Class Cestoda: Flatworms Parasitic flatworms: tapeworms Parasitic flatworms: tapeworms They have a head called a scolex suckers and hooks that allows them to attach themselves to their host They have a head called a scolex suckers and hooks that allows them to attach themselves to their host Attach to intestinal walls Attach to intestinal walls Food is absorbed through skin of parasite Food is absorbed through skin of parasite Reproduce: proglotidds: rectangular body sections. They are reproductive units that are added throughout the worms life. A proglottid can have up to 10,000 eggs. Reproduce: proglotidds: rectangular body sections. They are reproductive units that are added throughout the worms life. A proglottid can have up to 10,000 eggs. There are more than 5,000 species of tapeworms known to science, and nearly every species of vertebrate is liable to infection from at least one species of tapeworm. There are more than 5,000 species of tapeworms known to science, and nearly every species of vertebrate is liable to infection from at least one species of tapeworm.

6. Class Trematoda: Flatworms Largest class Largest class Parasitic worms called flukes Parasitic worms called flukes Endoparasitic: live inside the host Endoparasitic: live inside the host Ectoparasitic: live outside the host Ectoparasitic: live outside the host Have one or more suckers to attach to host. Use pharynx to suck body’s fluids for food. Have one or more suckers to attach to host. Use pharynx to suck body’s fluids for food. Reproduce: can have more than one host. EX: Shistosoma Reproduce: can have more than one host. EX: Shistosoma 1. Blood fluke responsible for shistosomiasis: found in tropics 2. People wade in infected water, and parasites bore through skin and make their way to blood vessels. This causes bleeding and of and make their way to blood vessels. This causes bleeding and of intestinal walls and liver damage. intestinal walls and liver damage. 3. Also includes a special species of a snail as part of their life cycle.

8. Roundworms Phylum Nematoda Phylum Nematoda Bilaterally Symmetry Bilaterally Symmetry Found Everywhere. Pets: wormed, soil, humans etc… Found Everywhere. Pets: wormed, soil, humans etc… They have a body cavity that forms between the gut and the body wall. Food passes into the mouth and is excreted through the anus. They have a body cavity that forms between the gut and the body wall. Food passes into the mouth and is excreted through the anus. Many nematodes are free living and play critical ecological roles as decomposers and predators on microorganisms. But nematodes also include parasitic species, a number of which affect humans directly or indirectly through their domestic animals. These include the common roundworms, which probably infest more than half the world's humans; hookworms; trichina, the worms that cause trichinosis and Ascaris worms; pinworms, another extremely common parasite, even in the United States, which can be transmitted from human to human by eggs floating in household dust; and filarial worms, primarily tropical parasites that cause diseases such as filariasis (elephantiasis) and onchocerciasis (river blindness). Many nematodes are free living and play critical ecological roles as decomposers and predators on microorganisms. But nematodes also include parasitic species, a number of which affect humans directly or indirectly through their domestic animals. These include the common roundworms, which probably infest more than half the world's humans; hookworms; trichina, the worms that cause trichinosis and Ascaris worms; pinworms, another extremely common parasite, even in the United States, which can be transmitted from human to human by eggs floating in household dust; and filarial worms, primarily tropical parasites that cause diseases such as filariasis (elephantiasis) and onchocerciasis (river blindness).

9. Ascaris Trichinella A cluster of nematodes, the roundworm of dogs, Toxocara canis.