Parasites - Parasites View the Parasite Presentation and...

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View the “Parasite” Presentation and answer the following questions. (Note: Some pictures in the presentation are graphic!) 1. Define parasite. Parasites are organisms which live in close contact with a host and depend upon that host for survival. 2. Name 5 symptoms associated with parasitic infections. Allergies, 3. How could one contract a parasitic infection? Parasites may be contracted from food such as improperly cooked meat, poorly washed vegetables and fruit which was grown using feces for fertilizer, or water contaminated with feces. 4. How has parasitism impacted humanity? Eendemic parasites render half of the land unsuitable for cultivation. The land is needed for producing food for the starving population. People near starvation are debilitated by parasites which feed on host intestinal fluids. Parasites debilitate people who are poorly fed. Parasites infect wild and domestic animals increasing the risk of human infection and making it difficult to use such animals for farming or to raise animals for food. 5. How do ectoparasites differ from endoparasites? Ectoparasites live on the surface of hosts; include ticks and lice. Endoparasites live within the host body; include protozoa and worms. 6. How does a definitive host differ from an intermediate host? Definitive hosts harbor a parasite while it reproduces sexually. Intermediate hosts harbor the parasite during some other developmental stage. 7. What adaptations are found in parasites? Explain each. Specific Structures -Parasitic organisms have lost digestive and sensory functions & live inside a host and feed on host fluid. The ability to monitor the environment; find and digest food is not needed. Parasitic worms develope structures for attachment such as hooks and suckers. Many parasites exhibit an increased reproductive capacity to compensate for the uncertainty of finding a new host. Tapeworms for example may lay up to 1,000,000 eggs per day. Ecological Ingenuity - Some organisms use special methods for surviving adverse environmental conditions. (1) Protozoa form cysts in order to survive until a new host is found. (2) Eggs of many worms have a protective coating to protect against drying. Many parasites show a complex infection and transmitting mechanism. Evading Host Defense Mechanisms - In order to survive successfully in a host, the parasite must develop means of living “in harmony” with the host. This process involves developing means of evading the host defense mechanisms. 8. Explain each method by which parasites evade host defense mechanisms. Encystment - parasites form a thick outer covering in order to protect themselves against unfavorable conditions in their environment. The resulting structure is called a cyst. During the cyst stage, internal reorganization of the organisms and cell
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This note was uploaded on 02/15/2012 for the course ENGL 1010 taught by Professor Stifler during the Spring '08 term at Chattanooga State.

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Parasites - Parasites View the Parasite Presentation and...

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