Community Ecology

• Community


  Ecological term for all the different species living together in an area
• Competition


  Organisms of two different species use the same limited resource and have a negative impact on each other
• Predation


  When the member of one species eats all or part of the body of a member of a different species. +/-
• Herbivory


  Specific type of predation where the member of one species eats all or part of the body of a species of plant +/-
• Mutualism


  A long term close association between two species in which both partners benefit +/+
• Commensalism


  A long term close association between two species where one partner benefits and the other is unaffected +/0
• Parasitism


  A long term close association between two species in which one benefits and one is harmed +/-
• Resource partitioning


  When two species that used to be in the same niche evolve by natural selection to use less similar resources so they both stand better chances of survival
• Symbiosis


  General term for interspecific interactions in which two species live together in a long-term, close association. Broader than its use in everyday life, because it includes relationships where parties are harmed
• Competitive exclusion principle


  Two species can't have the exact same niche in a habitat and stably coexist, because they would be competing for the exact same resources
• Species richness


  The number of different species present in a particular community. Communities with the most different species tend to be closer to the equator
• Species diversity


  Measure of ecological community complexity that is a function of both the number of species present, but also their relative abundances (how even a portion of total species they have)
• Factors that shape community structure

  • Climate patterns
  • Geography
  • Heterogeneity of the environment
  • Frequency of disruptive events
  • Interactions between organisms
• Foundation species


  Species that plays a unique role in an ecosystem, because once it is present, it allows for entire systems to be built around them (like grass or kelp)
• Keystone species


  Species that has a disproportionately large effect on community structure relative to its biomass or abundance. Different from foundation species because they are more likely to be on higher trophic levels, and are often so important because of their regulatory properties
• Invasive species


  A species that has been introduced to an area outside of its native range that has potential to do harm to the ecosystem by taking over or messing up the balance
• Human-mediated causes for biodiversity loss:

  • Land use change
  • Pollution
  • Introduced invasive species
  • Resource exploitation
• Conservation

  Working to protect species and the environments in which they live through things like legislation and captive breeding programs
• Biodiversity hotspot


  A biogeographic region that contains high biodiversity and is also threatened with destruction