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Ecology. Ecology. Relationships of living organisms to their environment. Ecological Concepts. Environment All conditions directly affecting animals existence Habitat The physical space inhabited by an animal Niche
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Ecology • Relationships of living organisms to their environment
Ecological Concepts • Environment • All conditions directly affecting animals existence • Habitat • The physical space inhabited by an animal • Niche • The specific multidimensional sets of conditions that define where an organism can exist
Ecological Concepts • Populations • Communities • Ecosystems
Ecological Concepts - Populations • Reproductively interacting members of a single species • Deme – • Any particular population separate from other populations of a species • Demographics • Age structure, sex ratio, growth rates, etc…
Population Dynamics • Growth rates • Birth rate – death rate = intrinsic growth rate • Carrying capacity • Upward limit on growth/size of a population • Intrinsic limits • Space, resources, intra-specific competition • Extrinsic limits • Biotic: Predation, parasitism, interspecific competition • Abiotic: fires, floods, etc…
Carrying Capacities 2012
Ecological Concepts -Communities • Co-existing populations of multiple species within the same habitat • Species diversity • # of species sharing a habitat and how abundant each species is • Species Richness • How many different species • Species evenness • How many individuals of each species
Populations - Interactions • Interspecific interactions • Detrimental (-) • Beneficial (+) • Neutral (0) • Predation • Parasitism • Commensalism • Mutualism • Competition • Keystone species • Any species whose removal from a population will cause extinction of other species
Character Displacement • Competition within a niche forces exclusion and adaptation competition no competition
Ecosystems • The transfer of energy among populations of organisms with a habitat • Trophic levels • Primary producers • Fix and store energy from outside the ecosystem – plants • Consumers • Primary – herbivores • Secondary – carnivores, insectivores • Decomposers – bacteria, fungi, nematodes, protozoa, annelids