BIO120H1 Lecture Notes - Lecture 21: Antonie Van Leeuwenhoek, Cleaner Fish, Intraspecific Competition
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BIO120H1 Full Course Notes
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Document Summary
Mutualism typically involves reciprocal exchange of foods or services between species. Nutritional e. g. legumes and rhizobia exchange fixed c for fixed n. Defensive e. g. ants and plants exchange protection for food. Dispersal e. g. plants and animals exchange seed dispersal for food. Third species such as a predator or a competitor. Diminishing returns to mutualism as the population grows. Positive feedback between mutualists tends to generate runaway population growth. Feed on ectoparasites on bodies of client fish, gain food and clients benefit from fewer parasites. Often have cleaning stations that clients visit. Experimentally removing cleaner fish increases parasite abundance on client fish. Aphids feed on phloem sap, have intracellular bacteria that provide hosts with essential amino acids since the sap is poor in amino acids. Bacteria is vertically transmitted (passed in eggs from mothers to offspring) Vertically transmitted endosymbionts typically have tiny genomes because they lose genes they no longer need.
