Community Ecology Structure and Species Interaction Connor McNeil and Daniel Crawford
Community Structure (aka Spatial Distribution) Described by: Physical Appearance: stratification, distribution, and relative sizes of population and species Species Diversity (Richness): number of different species Species abundance: number of individuals of each species Niche Structure: number of ecological niches, how the resemble of differ from each other and how they interact
Difference in Physical Appearance Terrestrial biomes consist of vegetation patches Difference in size Leads to boundries: Sharp edges: distinct Ecotones: Wider, more gradual transition zones
Distribution of Biodiversity Highest Biodiversity in Tropical Rain Forests However, High Biodiversity and Low Species Abundance Latitude: Latitude species diversity gradient : greater diversity in tropics, least at poles (terrestrial systems) Depth: increases to 2,000m, then decreases, until ocean surface, which has high diversity (aquatic systems)
Species Interaction Competition and Predation Intraspecific competition: members of the same species compete for resources Territoriality: Patrolling, marking, and/or defending home/nest/feeding sight Interspecific Competition: Competition between two or more species for resources
Competition Interference Competition: one species limits another’s access to resources Exploitation Competition: species have equal access to resources, but vary in speed and efficiency of exploitation.
Predator-Prey Relations Predator feed directly on Prey Individually harmful However, through predation, Prey species limited in abundance and increased access to food and genetic stock improved Use eyesight, speed, pack-hunting, etc Pursuit and ambush
Prey Naturally avoid being EATEN!!! Speed, Detection, Protection, etc. Camouflage, Mimicry Chemicals: Poison, Irritation, Smell, Bad Taste Enlargement
Symbiotic Species Both species helped: Parasitism* Lichens, Bacteria, Algae *Can be considered special type of predation
Commensalism One species helped; one unaffected Ex: Raccoons and human garbage
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