BIOL 1050 Lecture 29 Outline of Last LectureI. Frog deformity case studyII. Community ecology Outline of Current LectureI. Community Ecologya. Parasitismb. Mutualism c. Commensalism d. Disturbance of communities Current LectureI. Community ecologya. Parasitism i. A relationship in which one organism benefits and the other is harmedii. Parasite lives in or on the body of a host 1. Obtains nutrients from hostiii. Organisms have evolved many defenses against parasitesiv. Parasites are predators that benefit from a symbiotic relationship with theirhostsv. Ectoparasites1. Parasites that live on their hostvi. Endoparasites1. Parasites that live inside their hostvii. There may be 3 to 4 times as many parasitic species as non-parasitic specieson earthviii. Parasite ingenuity1. Parasites have evolved surprising methods to solve a challenging problem: how to get from one individual host to anothera. The rabies virus induces “rabid” behavior in animals it infects, including aggression and foaming at the mouth, which help it to spread to a new hostb. Mutualismi. An interaction between 2 species that benefits both partners ii. Wild bees pollinate 80% of U.S. crops, saving us $8 billion in U.S. aloneThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Benefit to flower: its sperm (within pollen) is carried to the female reproductive structures of another flower, enabling cross-pollination2. Benefit to bee: it obtains plenty of food in the form of nectar and excess pollenc. Commensalismi. Non-negative species interactionii. Interaction in which one species benefits and the other neither benefits or is harmed d. Keystone speciesi. A species whose activities play a dramatic role in determining the composition of the communityii. Many interactions have multiple indirect effects as welliii. A keystone species such as the sea star has an unusually large influence on the presence or absence of numerous other species in the community. When sea stars were removed from an area within an intertidal zone, species diversity decreased drastically-only mussels remainediv. Identifying keystone species is an important part of conservation biology-preserving just one keystone species has the effect of preserving many additional species at the same time e. Disturbance of communitiesi. Disturbances change biological communitiesii. Change in species composition over time after disturbance is called succession1. Primary successiona. Begins after a disturbance leaves an area barren of soil and with no life 2. Secondary successiona. Begins after a smaller disturbance with growth of species previously outcompeted by other species 3. Disturbance is often frequent and can prevent formation of a climax community 4. Colonizing communitya. Good dispersers, but poor competitors5. Intermediate communitiesa. Both colonizers and competitors present6. Climax communitya. Better competitors that persist as a stable
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