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32 Cards in this Set
- Front
- Back
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Ecology
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•Interactions between organisms and their biotic andabiotic environments.
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biotic
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otherorganisms & their products
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Intraspecific
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amongsame species
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Interspecific
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amongdifferent species
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abiotic
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–non-living environment
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(1) Organismal ecology
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howindividual organisms work within their environments
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organismal ecology includes
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–Physiological Ecology•Energy allocation, reproduction
–Evolutionary Ecology•Adaptations to environments –Behavioral EcologyHoworganisms act to accomplish certain goals |
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•Genetic influences on organismal ecology
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-Responses to stimuli, Tactic (movement), Tropism (growth), Migration.
–Signals & Communication. –Mating & Parental Behaviors. –Social interactions. |
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•Environmental influences. on organismal ecology
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–Learning, Association, Cognition.
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(2) Population ecology
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Studyof groups of organisms of the same species, usually living in a particular area
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population ecology includes
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–Ofteninvolves #’s
•Populationincrease/decrease •Fecundity(reproductive capacity) •Factorsinfluencing population size |
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big questions for population ecology
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•How do biotic and abiotic factorsinfluence the density, distribution, size, and age structure of populations?
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Interactions in populations
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•Intraspecific (same species)
•Population Size–Births/Immigration– Deaths/Emmigration–Growth •Births/Immigration> Death/Emmigration–GrowthRate (“Rate of Increase”) •Changesin Growth over time •Density = numbers/area |
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•certain assumptions must be met forExponential growth:
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1.Continuous reproduction (e.g., no seasonality)
2.All organisms are identical (e.g., same fecundity, no age structure) 3.Environment is constant in space and time (e.g., resources are unlimited) |
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•CarryingCapacity
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Most natural populations are eventually limited by the available resources, so environment (biotic and abiotic) limits population size. This leads to a logistic growth model
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•Dispersion = spacial distribution
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–Uniform
–Random –Clumped |
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Density Dependent Limiting Factors
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• food/water availability
• space • light • O2, CO2 or nutrients • mate availability (territoriality) • disease • increased predation (more prey) • increased waste production • intrinsic reproductive control |
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Density Independent Limiting Factors
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•temperature
•humidity •precipitation •presence of toxins •salinity •altitude/atmospheric pressure |
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Reproductive strategy: r-selection
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maximizes r (rate of increase) so that the species can rapidly colonize a new area (when conditions warrant)
•Opportunists, high birth rates, low overall survival of offspring. |
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Reproductive strategy: K-selection
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maximizes competitive ability, particularly in low density populations – N is almost equal to K (K=carrying capacity)
•Conservatives, low birth rates, high overall survival of offspring |
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Survivorship curves
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–TypeI– large mammals, ↑ parental care.
–TypeIII– plants, fish, ↓ parental care. –TypeII– many in between. |
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(3) Community ecology
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–Study of allorganisms of all speciesoccupying a particular area.
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Community ecology includes
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–Competition, Predation, Parasitism
–Disturbance –Succession –Community Structure –Energetics |
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Competition (-/-)
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Exploitive- •indirect usually, typically negativelyaffecting species.
for limited resources •Adaptations allow better (or poorer)resource exploitation (speed, root efficiency, etc.)•Competitive Exclusion •Resource Partitioning – to avoidcompetition.•Ecological Niche |
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Predation (+/-)
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•Feeding! -- One species benefits at theexpense of another species.
•Leads to many adaptations:–Crypticcoloration (Camouflage) •Forboth predator & prey!–Aposematiccoloration (Warning)–Mimicry(of unpalatable species) •(Herbivory) – a type of predation in which the preyis not killed, but is still at a disadvantage! –Aposematic& Mimicry in plants! –Chemical,Mechanical, & Symbiotic defenses. |
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Parasitism (+/-)
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•One species compromises another living host while living on or in it.
•Feeding, protection, reproduction •Complex lifecycles •Endoparasites, Ectoparasites •Disease – sometimes.–“Pathogens”= disease-causing agents |
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Mutualism (+/+)
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•“Symbiosis” between two organisms.•Both Benefit!
•Clownfish/Anemone, Ant/Acacia, Legume/Rhizobium. |
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Commensalism (+/0)
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•One species benefits, the other isneutral.•Algae on shells & fish, CattleEgrets, Insects following leafcutters/army ants.
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Changes in communities over time
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•Succession: progressive changes in communitystructure over time.
–PrimarySuccession– from bare rock. –SecondarySuccession– from some intermediate state. •Disturbance– may not always be bad“IntermediateDisturbance Hypothesis |
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Trophic structures of communities
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•FoodPyramids
•FoodWebs••Producers •1o consumers–(herbivores) •2o consumers- (carnovores, omnivores) •Decomposers |
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Control of community structure
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•“Top-Down” Control–Top predators “control” communitystructure.
•“Bottom-Up” Control–Producers/Herbivores “control” communitystructure •Foundation Species – establish & facilitatecolonization by others. •Keystone Species – Large roles in community, controllingother species’ fates. •Invasive Species – “new” species with few predators &fast growth. |
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diversity
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•Species Richness
•Species Evenness •“Functional Diversity”–emphasison species contributions, rather than on the species themselves. •Ties in with Ecosystem Functioning–RivetHypothesis–RedundancyHypothesisg |
