K1+The+Nature+of+Parasitism

Key Notes: Parasites are a subgroup of predators that live in close association with their host. There are two broad groups: -Most are viruses, bacteria, fungi, and/or protozoans. -These are dominated by invertebrates. ~A major group of macroparasites are parasitoids (lay eggs in or on the body of their insect host and usually cause the death of the host. **ex: wasps and flies** also known as **hyperparasites.** Viruse:** Measles**,** HIV, Flu Thyphoid, Scarlet Fever, Strep Ringworm Trypanosomes Plasmodium
 * K1 The Nature of Parasitism:**
 * Microparasites:** which multiply within or on the surface of the host.
 * Macroparasites:** which grow in or on the host but do not multiply.
 * Helminth worms and insects are very important Macroparasites*
 * Aphids are microparasites of plants (reproducing on teh surface of the plant)
 * Fungi can be macroparasites of insects and plants, not reproducing until the host is killed.
 * Biotrophs**: only survive on living tissue
 * Necrotrophs**: can continue to live on host after death.
 * Some diseases:
 * Bacteria:**
 * Fungi:**
 * Protozoan:**


 * Parasite transmission** can be among the members of a population **(horizontal)** this can be direct or indirect mediated by a vector like mosquito or an alternate host; or by mother to offspring **(vertical)**

Vertebrates:** infection by a microparasite results in a strong immunological response. Vertebrates exhibit **preening behavior**, which removes ectoparasites. e.x: Caribou avoid crazy mosquito times by **migrating** to a higher altitude. This is where the plant will kill the cells in that vicinity making it so the parasite has no food and dies off.
 * Host response to disease:
 * -The cellular immune response:** specialized cells directly attack pathogen cells
 * -The B-cell immune response:** gives rise to antibodies.
 * These cells will store and remember this attacker so next time it attacks they will have stronger forces to fight against it. **Immunological memory.**
 * Invertabrates and plants:** can suppress infection but not as well as vertebrates. The loss of potential hosts which ummunity engenders accentuates the boom-and-bust strategy of microparasites (section K2)
 * -Behavioral Strategies:**
 * -Localized cell death = plant defence.**

-**Obligately Switch:** where parasite species will move between two or three host species. -Host originally is a vector (been attacked by the parasite to increase its reproductive output) -Optimal habitat use (depends on which animal is in the area of the food source at the time) -Evolutionary constraint (when there are multiple hosts they each will have different uses one host for sexual usage, social on others)
 * Complex life Cycles:**
 * Three reasons:**

-**these parasites gain benefit from their animal hosts by getting them to provide them with food or other useful things. -Species of parasites or even species like bees or birds will lay their egg in a host nest and get that host to take care of those eggs.
 * Social Parasites: