Community Ecology
* Community
* All organisms that live together in a place
* Interactions
* The study of interactions among all populations in a common environment
Niche
* Ecological role
Niche and Competition
* Competitive exclusion
* No two similar species can occupy the same niche at the same time
Predation Drives Evolution
* Predators adaptations
* Locate and subdue prey
* Prey adaptations
* Elude and defend
Anti-predator Adaptations
* Hide from predators
* Avoid detection
* Camouflage
* Warn predators
* Advertise how undesirable they are as prey
* Aposematic coloration
* Batesian mimicry
* Resemble the defensive signaling of a defended species
* Müllerian mimicry
* Two or more protected species look like each other
Coevolution in Community
* Predator-prey relationships
* Parasite-host relationships
* Flowers and pollinators
Characterizing a Community
* Community structure
* Species diversity
* How many different species
* Composition
* Dominant species
* Most abundant species
* Highest biomass
* Keystone species
* Changes over time
* Succession
Species Diversity
* Greater diversity means greater stability
* Greater biodiversity offers:
* More food resources
* More habitats
* More resilience in face of environmental change
Keystone Species
* Influential ecological role
* Exert important regulating effect on other species in the community
* Keystone species increases diversity in habitat
Ecological Succession
* Sequence of community changes
* Transition in species composition over time
* Usually after a disturbance
* Primary Succession
* Begins with a virtually lifeless areas, without soil
* Bacteria
* Lichens
* Mosses
* Grasses
* Shrubs
* Trees
* Secondary Succession
* Existing community cleared, but base soil is still intact
* What causes succession
* Tolerance
* Early species are weedy r-selected
* Tolerant of harsh conditions
* Facilitation and Inhibition
* Early species facilitate habitat changes
* Change soil pH
* Change soil fertility
* Change light levels
* Allows other species to out-compete
Climax Forest
* Plant community dominated by trees
* Representing final stage of natural succession for specific location
* Stable plant community
* Remains essentially unchanged in species composition as long as site remains undisturbed