1 / 45

Chapter 53 Community Ecology

Chapter 53 Community Ecology. Community Assembly of populations of different species living close enough for interaction Large-river bank community Small-rotting log. http://www.dkimages.com/discover/previews/995/80019640.JPG. http://members.fortunecity.com/nrbq1/gal1tarriverbank12.jpg.

polly
Download Presentation

Chapter 53 Community Ecology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 53Community Ecology • Community • Assembly of populations of different species living close enough for interaction • Large-river bank community • Small-rotting log http://www.dkimages.com/discover/previews/995/80019640.JPG http://members.fortunecity.com/nrbq1/gal1tarriverbank12.jpg

  2. Interspecific interactions • Interactions with members of another species http://www.biology.wustl.edu/faculty/knight/trilliumimage2.jpg

  3. Interspecific interactions • 1) Competition (-/-) • Both parties suffer • Resources in short supply • Ex. Weeds/grass http://www.raisethehammer.org/images/weeds_exhibit_1.jpg

  4. Competitive Exclusion Principle • G.F. Gause • 2 species competing for same resource can’t coexist in same place • 1 species will be more efficient/have a reproductive advantage=local elimination of 1 species

  5. Ecological Niche • The ecological role or “profession” of the organism in the environment • 2 organisms cannot occupy the same niche

  6. A. Resource Partitioning • Modification/differentiation of a niche to allow species to coexist http://kentsimmons.uwinnipeg.ca/16cm05/1116/53-03a-ResourcePartition-L.gif

  7. B. Character Displacement • Allopatric (separate) population • Morphologically similar, use similar resources vs. Sympatric (overlapping) population • Diff. body structures, diff. resources • Ex. Beak size in Galapagos finches

  8. Interspecific interactions • 2) Predation (+/-) • Predators possess adaptations for capturing prey • Prey possess adaptations that help avoid being eaten

  9. A. Cryptic coloration • Camouflage

  10. B. Aposematic coloration • Bright colors for those with chemical defenses

  11. C. Batesian mimicry • Harmless species mimics harmful one

  12. D. Mullerian mimicry • 2 or more species mimic each other • Speeds predator learning to not eat them

  13. Interspecific interactions • 3) Herbivory (+/-) • Occurs when herbivore eats a plant • Plants defend by • Chemical toxins • Spines/thorns http://www.stri.org/english/about_stri/media/press_releases/fotos/pr_herbivory.jpg

  14. Interspecific interactions • 4) Parasitism (+/-) • Parasite derives nourishment from host • Effect survival, reproduction, and pop.density of host http://www.dfo-mpo.gc.ca/regions/CENTRAL/science/images/lamprey_parasitism.jpg http://www.cals.ncsu.edu/entomology/gould/Gould%20Lab/images/parasitism.jpg

  15. Interspecific interactions • 5) Disease (+/-) • Pathogens weaken and can be lethal to host http://www.chemistryquestion.com/images/Question/legionella.jpg http://www.leprosy.ca/atf/cf/%7B3B422F46-F1B0-456B-9C29-14D45D964C11%7D/Saleh%202.jpg

  16. Interspecific interactions • 6) Mutualism (+/+) • Both benefit from interaction • Ex. Bacteria/roots, plants/pollinators http://www.cbu.edu/~seisen/ExamplesOfMutualism_files/image005.jpg http://www.bio.usyd.edu.au/DavidDay/root_nodules.jpg

  17. Interspecific interactions • 7) Commensalism (+/0) • One benefits, other is neutral • Ex. Hitch-hikers, cattle egrets

  18. Species diversity • Influenced by: • Species richness-total # of diff. species • Relative abundance=proportion of each species in the community

  19. Which has more species diversity?

  20. Trophic levels • Show energy transfer between individuals in a community

  21. Food chain: one-way path

  22. Food web: interweaving/linking of food chains

  23. Questions???? • How long can food chains be? • Why are food chains so short?

  24. Energetic hypothesis • Rule of 10% limits how much of energy is available further up the chain.

  25. Dynamic stability hypothesis • Long chains are unstable • Pop. fluctuations at lower links magnified higher up • Environmental setbacks magnified • Physical size further up chain

  26. Dominant species • Most abundant, highest biomass in the community • Exert powerful control over other species • Ex. Maple trees shade limits other plants • What happens when they are removed?

  27. Keystone species • Not most abundant • exert powerful control due to pivotal role

  28. Foundation species(ecosystem engineers) • Cause physical changes in community • Cause positive effects on survival/reproduction of other species http://www.tightline.biz/Beaver%20Dam%202.jpg

  29. Trophic level models • 1)Bottom-up (NVHP) • nutrient availability controls biomass at each higher level • 2)Top down (NVHP) • Predator levels control biomass at each lower level

  30. Biomanipulation • Use these simple models to fix communities that are out of line • Ex. Lake Vesijarvi, Finland http://www.mythinglinks.org/LakeSaimaaEasternFinland~R75~seasons4.jpg

  31. The effect of disturbances on a community • Traditional view was: • “balance of nature” unless disturbed by human activities • Current view is: • nonequilibrium-constant change is the norm after a disturbance

  32. Disturbance • An event that changes a community, removes organisms, or alters a resource • High level • High intensity and high frequency • Low level • Low intensity or low frequency • Intermediate level • Moderate disturbances create diversity

  33. Pictures of disturbance in BWCA http://wildfirelessons.net/uploads/before_after.JPG

  34. Cavity Lake Fire-2006 http://199.134.225.50/nwcc/t1_pnw2/2006/cavity-lake/digital-library/large/20060716-day3-12.jpg

  35. Recovery begins from disturbance http://www.gunflint-trail.com/canoetrips/images/gta_300x200_burn_tusc.jpg

  36. Ecological succession follows disturbance of a community • Gradual replacement one group of species by another • Primary succession • Occurs when no soil present • Ex. volcanic island, retreating glacier • Secondary succession • Occurs when existing community cleared by a disturbance • Ex. fire, clear-cutting, abandoned fields

  37. Biogeographical effects on communities • Equatorial-Polar gradient • Further from equator, less diversity and abundance………why? • 1)5x longer growing season than tundra • 2)no “start-overs” due to ice ages/glaciers • 3)climate • Higher amount of solar energy, temps, and water

  38. Community structure • Integrated hypothesis • Community is assembly of closely linked species that together function as a unit • Individualistic hypothesis • Chance assembly of organisms because they have similar abiotic requirements

More Related