Biology 2483A Lecture 12: Bio 2483 Lecture 12
14 Jan 2019
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Document Summary
Some parasites can alter the behaviour of their host in order to complete their life cycles: parasites typically feed on only one or a few host species, but host species have multiple parasite species. Ectoparasites: live on outer body surface of the host. Endoparasites: live inside their hosts, within cells or tissues or in the alimentary canal: microparasites: microscopic, such as bacteria, macroparasites: large species such as arthropods and worms. Includes parasitic species: cause tinea (athlete"s foot, ringworm, and jock itch) Leprosy (hansen"s disease (hd)): long term infection by the bacterium mycobacterium leprae or. Many species are host to more than 1 parasite species: hosts have mechanisms for defending themselves against parasites, and parasites have mechanisms for overcoming host defenses. Plants also have defense systems: resistance genes, non-specific immune responses such as antimicrobial and antifungal compounds, chemical signals that warn nearby cells of imminent attack, chemicals that stimulate deposition of lignin, making a barrier to an invader"s spread.
