1 Community EcologyChapter 47Mader: Biology 8th Ed.
2 Diversity and Composition Models Island Biogeography OutlineDiversity and Composition ModelsIsland BiogeographyHabitat and Ecological NicheCompetition Between PopulationsPredator-Prey InteractionsSymbiotic RelationshipsCommunity DevelopmentCommunity DiversityMader: Biology 8th Ed.
3 Composition is a listing of various species in the community. Community ConceptA community is an assemblage of populations interacting with one another within the same environment.Composition is a listing of various species in the community.Diversity includes both species richness and species diversity.Mader: Biology 8th Ed.
4 Diversity and Composition Models Gleason - Individualistic ModelEach population in community is there because its own particular abiotic requirements are met by a particular habitat.Clements - Interactive ModelCommunity is the highest level of organization.Dependent on biotic interactions.Mader: Biology 8th Ed.
5 Island BiogeographyMacArthur and Wilson developed a general model of island biogeography to explain and predict the effects of distance from the mainland and size of an island on community diversity.Island size and distance from population source affects species diversity.Mader: Biology 8th Ed.
6 Model of Island Biogeography Mader: Biology 8th Ed.
7 Community StructureCompetition for limited resources between two species has a negative effect on the abundance of both species.Predation and parasitism are expected to increase the abundance of the predator and parasite at the expense of the abundance of the prey and its host.Mader: Biology 8th Ed.
8 Habitat and Ecological Niche Habitat is the area an organism lives and reproduces in.Ecological niche is the role an organism plays in its community, including its habitat and its interactions with other organisms.Fundamental niche - All conditions under which the organism can survive.Realized niche - Set of conditions under which it exists in nature.Mader: Biology 8th Ed.
9 Feeding Niches for Wading Birds Mader: Biology 8th Ed.
10 Competition Between Populations Interspecific competition occurs when members of different species try to utilize a resource in limited supply.Competitive Exclusion Principle - No two species can occupy the same niche at the same time.Resource Partitioning decreases competition.Can lead to character displacement.Mader: Biology 8th Ed.
11 Competition Between Barnacle Species Mader: Biology 8th Ed.
12 Character Displacement in Galápagos Finches Mader: Biology 8th Ed.
13 Predator-Prey Interactions Predation occurs when one living organism, the predator, feeds on another, the prey.Presence of predators can decrease prey densities, and vice-versa.Mader: Biology 8th Ed.
14 Lynx-Snowshoe Hare Interactions Mader: Biology 8th Ed.
15 Prey DefensesPrey defenses are mechanisms that thwart the possibility of being eaten by a predator.SpinesTough EpidermisPoisonous ChemicalsCamouflageBright ColorationFlocking BehaviorMader: Biology 8th Ed.
16 Camouflage in the Anglerfish Mader: Biology 8th Ed.
17 Batesian - Mimic lacks defense of the organism it resembles. MimicryMimicry occurs when one species resembles another that possesses an overt antipredator defense.Batesian - Mimic lacks defense of the organism it resembles.Müllerian - Mimic shares same protective defense.Mader: Biology 8th Ed.
18 Symbiotic Relationships Symbiosis refers to interactions in which there is a close relationship between members of two populations.ParasitismParasite derives nourishment from a host, and may use host as habitat and mode of transmission.EndoparasitesEctoparasitesMader: Biology 8th Ed.
19 Many examples may turn out to be mutualism or parasitism. CommensalismCommensalism is a symbiotic relationship in which one species is benefited and the other is neither benefited nor harmed.Remoras and SharksMany examples may turn out to be mutualism or parasitism.Amount of harm or benefit two species do to one another is partially determined by the investigator.Mader: Biology 8th Ed.
20 Often help organisms obtain food or avoid predation. MutualismMutualism is a symbiotic relationship in which both members of the association benefit.Often help organisms obtain food or avoid predation.Bacteria in human intestinal tact.Need not be equally beneficial to both species.Cleaning SymbiosisMader: Biology 8th Ed.
21 Mutualism Between Bullhorn Acacia and Ants Mader: Biology 8th Ed.
23 Community Development Ecological SuccessionA change involving a series of species replacements in a community following a disturbance.Primary Succession occurs in areas where there is no soil formation.Secondary Succession begins in areas where soil is present.Pioneer SpeciesMader: Biology 8th Ed.
24 Secondary Succession in a Forest Mader: Biology 8th Ed.
25 Succession Models Facilitation Model Succession in a particular area will always lead to the same type of community.Climax CommunityEach stage facilitates invasion and replacement by organisms of the next stage.Mader: Biology 8th Ed.
26 Different types of plants can colonize an area at the same time. Succession ModelsInhibition ModelColonists hold onto their space and inhibit growth of other plants until the colonists are damaged or die.Tolerance ModelDifferent types of plants can colonize an area at the same time.Chance determine which seeds arrive first.Mader: Biology 8th Ed.
27 Community stability can be recognized in three ways. Community DiversityCommunity stability can be recognized in three ways.Persistence through time.Resistance to change.Recovery once a disturbance has occurred.Mader: Biology 8th Ed.
28 Intermediate Disturbance Hypothesis Moderate amounts of disturbances at moderate frequency are required for a high degree of community diversity.If widespread disturbances occur frequently, diversity will be limited.Mader: Biology 8th Ed.
30 Predation, Competition, and Biodiversity In certain communities, predation by a particular species reduces competition and increases diversity.Predators that regulate competition and maintain community diversity are referred to as keystone predators.Introduction of exotic species into a new area may lead to unbridled competition and resultant reduction in biodiversity.Mader: Biology 8th Ed.
31 Diversity and Composition Models Island Biogeography ReviewDiversity and Composition ModelsIsland BiogeographyHabitat and Ecological NicheCompetition Between PopulationsPredator-Prey InteractionsSymbiotic RelationshipsCommunity DevelopmentCommunity DiversityMader: Biology 8th Ed.