Chapter 54 - Community Ecology unit. PDF

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Community Ecology unit.
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Chapter 54 Community Ecology Community Ecology • The study of the interactions between the species in an area Interspecific Interactions • Interaction between species may be positive, negative, or neutral Ex: 1. Coevolution 2. Predation 3. Mimicry 4. Competition 5. Symbiosis • Coevolution • When two species have reciprocal evolution to each other Ex: Flowers and their pollinators 2. Predatory (+/-) • Predator and prey relationships Ex: lynx and hares Herbivory (+/-) • When an organism eats parts of a plant or algae Herbivore – may have special adaptations to find their prey Plants – may have adaptations to avoid being eaten • Predation/Herbivory • Often results in interesting defenses or adaptations Ex: Cryptic coloration: A passive defense where the prey is camouflaged against its environment Aposematic coloration: The use of conspicuous colors in toxic or unpalatable organisms to warn off predators EX) poison arrow frogs 3. Mimicry • Defense mechanism where the mimic has a resemblance to another species, the model Types: • Batesian: Palatable species mimics an unpalatable model • Müllerian: Two unpalatable species resemble each other Competitive Exclusion Principle • Predicts that two species with the same requirement cannot co-exist in the same community • One species will survive and the second will go extinct Ecological Niche • The n-hyperspace of requirements for a species • How a species “fits into” an ecosystem • Species can not have niche overlap, the Competitive Exclusion Principle Niche Types 1. Fundamental - what a species is theoretically capable of using 2. Realized - what a species can actually use

Resource Partitioning - A way that species avoid niche overlap by splitting up the available resources Symbiosis - When two different species live together in direct contact Types: 1. Parasitism (+/-) • Parasite harms the host • Parasites may be external or internal • Well adapted parasites don't kill the host 2. Commensalism(+/o) • one partner benefits while the other is unchanged 3. Mutualism (+/+) • Both partners benefit from the interaction Species with large impacts • Some species have larger impacts on a community structure than others Ex: Dominant species, • A species that is the most abundant or has the highest biomass in a community has a major effect on a community both biotically and abiotically Keystone species, Foundation species...