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Community Structure and Biodiversity

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Community Structure and Biodiversity

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    1. Community Structure and Biodiversity Chapter 29

    3. Niche A description of the way a species utilizes its habitat - Fundamental niche? All ways a species could utilize resources if it did not have to compete for them. - Realized niche? Actual way a species utilizes resources under the influence of competition and other factors.

    4. Species Interactions Most interactions are neutral Commensalism helps one species and has no effect on the other (ex. Birds in Trees) Mutualism helps both species. (ex. Bees and Flowers) Predation and parasitism both benefit one species at a cost to another Parasite -

    5. Competitive Exclusion Principle When two species compete for identical resources, one will be more successful and will drive out the other.

    6. Prey defense: Camouflage

    7. Prey defense: Mimicry

    8. Predator Responses Predators counter prey defenses with new adaptations stealth camouflage avoidance of chemical repellents

    9. Ecological Succession Over time, one array of species is replaced by another

    10. Pioneer Species Colonize barren habitats Help create or improve soil Improve conditions for other species that then replace them Example: Small plants that form on volcanic islands.

    11. Community Instability Disturbances can cause a community to change in ways that persist even if the change is reversed Keystone species A species that has a disproportionately large effect on community structure Removal can cause drastic changes in a community

    12. Keystone Species

    13. Species Introductions Exotic species A species moves out of its home range and takes up residence in a new place No natural enemies or controls Can out compete native species Geographic dispersal slow or rapid movement

    14. Kudzu in Georgia Imported for erosion control No natural herbivores, pathogens, or competitors May turn out to have some commercial use

    15. Rabbits in Australia Rabbits were introduced for food and sport hunting Without predators, their numbers soared Attempts at control using fences or viruses have thus far been unsuccessful

    16. Diversity by Latitude Diversity of most groups is greatest in tropics; declines toward poles

    17. Biodiversity and Extinction 99.9% of all species that have ever lived are now extinct Biodiversity is greater than ever Current range of biodiversity is the result of past extinctions and recoveries

    18. Undiscovered Life

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