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Community Ecology

Community Ecology. Chapter 54. Interspecific Interactions. Competition --/-- Competitive exclusion Ecological Niches (Habitat-address; niche-profession) Resource partitioning-allows similar species to coexist in a community Fundamental niche-potential

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Community Ecology

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  1. Community Ecology Chapter 54

  2. Interspecific Interactions • Competition --/-- • Competitive exclusion • Ecological Niches (Habitat-address; niche-profession) • Resource partitioning-allows similar species to coexist in a community • Fundamental niche-potential • Realized niche-actual-may be result of interspecific competition

  3. Character Displacement • Tendency for characteristics to diverge more in sympatric pop of 2 species than in allopatric pop

  4. Predation +/-- • Can be animal eating plant tissues • Defensive adaptations • Cryptic coloration

  5. Aposematic coloration-warning

  6. Batesian mimicry-harmless or palative looks bad

  7. Mullerian mimicry • 2 unpalatable species look alike

  8. Herbivory +/-- Plants have chemical toxins, spines, thorns ex strychnine, nicotine, selenium toxins Herbivores-special adaptations • Insect-chemical sensors • Sense of smell • Specialized teeth • Length of digestive systems

  9. Symbiosis • Parasitism +/-- • Mutualism +/+ obligate; facultative • Commensalism +/0

  10. Species Diversity • Species richness • Relative abundance

  11. Shannon diversity (H) • Index based on species richness and relative abundance

  12. Trophic structure • Food Chain

  13. Food Webs (Elton 1920s)

  14. Limits on length of foodchain • Energetic hypothesis-inefficiency of energy transfer -10% rule • Dynamic stability hypothesis-long food chains are less stable than short ones-population fluctuations at lower trophic levels are magnified at higher levels • Also-carnivores tend to be larger at successive trophic levels-can’t get enough food to meet needs

  15. Dominant species • Most abundant-have the highest biomass • Exert a powerful control • Are they are competitively superior in exploiting limited resources? • Are they are most successful at avoiding predation?-would explain effect of invasive species…

  16. Invasive pressure • American Chestnut • Before 1910-40% of US trees-fungal disease- Chestnut blight-killed all the trees-oak, hickory replaced; mammals, birds ok, but 7 species of moths and butterflies became extinct

  17. Keystone species

  18. Foundation species • Ecosystem “engineers” • Affect by causing physical changes in the environment • Ex beavers • Facilitators-may help other species

  19. Models of organization • Bottom up VH • NVHP • Top down VH • NVHP Trophic Cascade • Biomanipulation-prevent algal blooms by adding consumers rather than chemicals

  20. Disturbance • Influences species diversity and composition • Storms, waves, fires, freezing, drought, • Moderate disturbance can foster greater diversity than low or high levels

  21. Ecological succession • Species are replaced by other species • Primary • Secondary • Climax community

  22. Island Equilibrium Model

  23. Detritivores • Return nutrients to the soil • Law of conservation of mass

  24. Aquatic Ecosystem • Light limitation • Nutrient limitation • Eutrophication

  25. Biomass-dry mass

  26. Phytoplankton continually replace their biomass at such a rapid rate, they can support a biomass of zooplankton bigger than their own biomass.

  27. The Green World Hypothesis • Terrestrial herbivores are held in check by a variety of factors.

  28. Transitional Page

  29. Productivity • GPP-gross primary production • NPP-net primary production • NPP=GPP – R(autotrophic respiration) • Primary production • in aquatic is mostly affected by light and nutrients-N and P • Eutrophic-nutrient rich • On land-temp and water • evotranspiration

  30. Biogeochemical cycles

  31. Nitrogen cycle

  32. Additional Terms • Bioremediation-use of organisms to detoxify polluted areas • Bioaugmentation-add desirable species such as nitrogen fixers • Biodiversity (3 Levels)-genetic diversity, species diversity and ecosystem diversity • Threats: habitat loss, introduced species, over-harvesting, global change

  33. Population conservation • Focuses on: • Population size • Genetic diversity • Critical habitat

  34. MVP • Minimum Viable Population • Extinction Vortex

  35. Landscape and regional conservation • Habitat fragmentation • Movement corridors • Biodiversity hot spot-small area with an exceptional concentration of endemic species

  36. Human Actions • Agriculture-nutrient cycling-take it out of soil or too much in water • Acid precipitation • Biological magnification • Greenhouse effect • Global warming • Ozone layer

  37. Elements www.animationfactory.com

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