Community Interactions AP Biology - 2005 AP Biology - 2005

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Transcript of Community Interactions AP Biology - 2005 AP Biology - 2005

  • Community Interactions AP Biology - 2005

  • CommunityA division of an ecosystem that describes all of the organisms that live in an areaFocuses on interactions within the communityEstablishes a niche a set of conditions under which an organism exists

  • InteractionsFocus on resources available in the communityFoodWaterSpaceMatesNesting sitesHiding placesLightMacro and micronutrients

  • Limiting ResourcesThere are only so many resources in a community for all of the organismsThis limits the growth of populations of organisms within this communityIt leads to specialized interactions within the members of this community( population dynamics)

  • InteractionsInterspecific Between different speciesIntraspecific Within the same species

  • Interaction links and Examples

  • Ecological relations( 1)One organism benefits in a relationship the other is harmed or is eatenExample predator prey and parasite = hostRating +/-Lynx and hare predator and preyMalaria, red blood cell, and human parasite and hosts

  • Cyclic predator-prey relationships

  • Experiment

  • Experiment( con)

  • Ecological relations( 2)Two organisms compete for the same resources. This is known as competition.Rating -/- or +/-ExamplesCompetition for mates intraspecificCompetition for space plants allelopathyCompetition for nutrients and space fungi and bacteria - antibiotics

  • MutualismBoth organisms benefitRating +/+Zooxanthellae and coral polypLegumes and RhizobiumLeaf cutter ant and fungal gardenAnt and acacia

  • Leaf cutter ants and fungal gardens

  • Ant and the Acacia

  • CommensalismOne organism benefits the other is neither harmed or benefits+/0Examples Pinnepidia crab and tube worm

  • AmensalismAnimals can have a negative effect on the environment0/-Animals trampling the grass on the way to the water hole

  • Contradictions

    Not all organisms fit the description exactlyThe definition for symbiosis is changing to include only those interactions between organisms of two different species whose metabolism is altered by the interaction

    psidelsky - The concept of symbiosis has changed due to recent advances in molecular biology and genetics that demonstrates the novel genes and adaptations that have occurred as the result of intimate relationships between two different organisms

  • Competition- InterspecificAllelopathy How plants guard their space by releasing molecules into the environment that deters other plants from occupying their space

  • Intraspecific Competition

  • Interspecific CompetitionBarnacle species on a rocky shoreEstablishes zonation of organismsNiche determined by ability to barnacles to tolerate dehydration

  • Competition may restrict species ranges.Two species of barnacles live on North Atlantic seashores, but as adults, one species lives higher in the intertidal zone than the other, with little overlap between the two (a phenomenon called intertidal zonation).If one of the species is removed experimentally, the vertical range of the other species becomes greater.The higher-zone barnacle outcompetes the other because it is more hardy when exposed to air; in the lower zone, the other barnacle is able to smother or crush higher-zone intruders.

  • Barnacle Competition

  • Batesian MimicryTwo different species resemble each other. One is unpalatable. The palatable receives the benefit of birds not wishing to eat it because they have eaten the unpalatable one with bad results.

  • It pays to advertise

  • Keystone Species keystone species is a species whose very presence contributes to a diversity of life and whose extinction would consequently lead to the extinction of other forms of life. Keystone species help to support the ecosystem (entire community of life) of which they are a part.

  • SuccessionSuccession begin when an area is made partially or completely devoid of vegetation because of a disturbance. Some common mechanisms of disturbance are fires, wind storms, volcanic eruptions, logging, climate change, severe flooding, disease, and pest infestation.

  • Plant Succession

  • Succession in a Glacial Moraine

  • Degradative successionThe dead body of an organism is reduced to basic molecules by decomposersPlants may produce litterDeciduous trees may produce layer of litter - compost

  • CoevolutionThe changes in one species may affect the changes in another species over timeAdaptations may occurThe organisms can develop a close associationPollinators and flowers a key example of coevolution

  • Yucca Moth

  • Yucca and mothFemale yucca moths only lay their eggs in the ovules of yucca flowers. A female Tegeticula( Yucca moth) lays no more than 5 eggs in the ovules.After she has laid the eggs she scrapes the pollen from the flowers anthers and flies to another Yucca where she transfers the pollen and lays 5 more eggs

  • Island BiogeographyImmigration of mainland species to island birds flying other animals and plants and animals drifting on trees or floating on rafts of vegetation in the currents in the ocean( new plants and animals) Seeds also carried by birdsIsolation of species after immigrationNovel adaptationsNew species develop allopatric speciationNew genetic species

  • Galapagos

  • Darwins finches and the Galapagos Islands