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Community Ecology. Chapter 47. Outline. Diversity and Composition Models Island Biogeography Habitat and Ecological Niche Competition Between Populations Predator-Prey Interactions Symbiotic Relationships Community Development Community Diversity. Community Concept.
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Community Ecology Chapter 47
Outline • Diversity and Composition Models • Island Biogeography • Habitat and Ecological Niche • Competition Between Populations • Predator-Prey Interactions • Symbiotic Relationships • Community Development • Community Diversity
Community Concept • What is a community? • Factors to consider • Composition is a listing of various species in the community. • Diversity includes both species richness and species diversity.
Diversity and Composition Models • Gleason - Individualistic Model • Each population in community is there because its own particular abiotic requirements are met by a particular habitat. • Clements - Interactive Model • Community is the highest level of organization. • Dependent on biotic interactions.
Island Biogeography • MacArthur and Wilson--effects of distance from the mainland and size of an island on community diversity. • Conclusions?
Habitat and Ecological Niche • Habitat -- Home. • Ecological niche ---occupation in the community • Fundamental niche - potential • Realized niche - actual
Species interactions • Community interactions can be potent selective pressures • Competition • Intraspecific • Interspecific • Predator/Prey • Symbiosis
RESULTS OF INTERACTION • (+) organism benefits (how?) • (-) organism suffers (how?) • (0) neutral, no benefit or loss (RU sure?)
Competition Between Populations • Intraspecific competition (?) • Interspecific competition (?) • Competitive Exclusion Principle • Resource Partitioning decreases competition. • Can lead to character displacement.
Predator-Prey Interactions • Predation • Selective pressure? • Interaction = +, - • Population effects
Prey Defenses • Prey defenses -adaptations that thwart the possibility of being eaten by a predator. • Concealment/cryptic coloration/other coloration • Warning coloration • Armor/weaponry • Chemicals • Behavior
Gecko Gecko?
Mimicry • Mimicry occurs when one species resembles another that possesses an overt antipredator defense. • Batesian – Harmless mimics harmful • Müllerian – Harmful mimics harmful
Batesian I: Coral snake or Milk Snake? Would you bet your life on it?
Vertebrate Eye Mimicry • Similar to Batesian • Can startle or confuse predator
Symbiotic Relationships • Symbiosis close relationship between members of two populations. We’ll be interested in 3: • Parasitism (+, -) • Commensalism (+, 0) • Mutualism (+,+)
Parasitism (+, -) • Endoparasites Ex? • Ectoparasites EX? • Social Parasites • Brood parasites • Kleptoparasites
Endoparasite Life cycles • Complex, spend different stages in different hosts • Definitive host (primary host) • Intermediate host
Brood Parasitism--European Cuckoo • The behavior of the cuckoo hatchling ejecting the host eggs from the nest • The feeding behavior of a foster mother to the cuckoo chick Figure 37.3B
Commensalism --+, 0 • Shark (0) • Remora (+)
Pseudocopulation Some orchids offer no nectar at all, but they resemble the female of various insect species. Or at least, resemble closely enough to fool a desperate male of the species – the mimicry is chemical as well as visual. The unfortunate male has to be deceived twice and engage in two acts of pseudocopulation before pollination takes place. Common european species doing this are the bee orchids in the genus Ophrys. In fact some populations of bee orchid seem to be self-fertile in the absence of pollination. Bee orchid Ophrys apifera
Mutualism • Mutualism (+,+) both members of the association benefit. • ADVANTAGES? • EX?