Biological communities, species interactions and...
Transcript of Biological communities, species interactions and...
Biological communities, species interactions and evolution
• Community• Species interactions• Community Dynamics• Succession: Primary and Secondary• Species composition & Distribution• Conservation Biology & Island
biogeography
Community• What is a community?• Chance assemblage of species?• Individualistic hypothesis• Interactive hypothesis• Continuous vs discrete boundaries
Ecological Niche
• Fundamental Niche
Potential niche with physical constraints
• Realized NicheActual niche with
biological constraints
Species InteractionsPredator-Prey relationships
Parasites
Keystone Predator
• Keystone species• Impact on community
structure• Maintain species
diversity• Examples• Pisaster (sea star)• Sea Otter
Kelp Forest
• Community structure• Sea urchin• Sea Otter
Symbiosis
• Commensalism• Mutualism
Competition
• Competitive exclusion Principle
• Avoidance• Resource partitioning
Community Dynamics
• Changes over time• Change in species #• Change in species
composition
Succession:• Two types:• Primary• Secondary• Pioneer
species:mosses• Species can facilitate/or
inhibit the entry of other species into the community
• Can reach a climax community
Succession: Secondary
• Existing communities have been cleared
• Soil present• Volcanic explosion• Farming• Fire
Succession: Secondary
Succession: Secondary
• Periodic disturbance
• Disclimaxcommunities: fire/ herbivores
• Community Senescence
Community Characteristics
• Species richness# of species
• Species abundance# present in each
species• Biodiversity
Biodiversity: Rare vs Common Spp
Threat of introduced species