Collection of interacting organisms of different species within an ecosystem.
The variety of different kinds of organisms.
1. Species richness
2. Relative abundance
3. Species diversity
Total number of different spp in the community
Size of populations of different spp in the community
The number and relative abundance of spp in a community.
Other Properties of a Community
1. Prevalent Form of Vegetation.
3. Trophic Structure.
Encounters be-tween members of different species.
Three main types of interspecific interactions: Competition, Predation,Symbiosis
Competitive Exclusion Principle
Populations of two spp cannot coexist in a community if their niches are nearly identical. Usually results in one spp dying out, moving out, or adapting to occupy another niche. Possible mechanism for natural selection.
When populations of two or more spp in a community rely on similar limiting resources.
2. Resource partitioning
Sum total of spp use of biotic and abiotic resources in the environment (eco-logical role in nature - job). Example:birds of prey - diurnal v. nocturnal.
Differentiation of niches that enables similar spp to co-exist in a community (Darwin’s finches).
Predator: Organism that eats another.
Prey: Organism that gets eaten by another (food).
1. Acute senses
2. Ability to catch and subdue prey.
3. Fast and agile (pursuit).
4. Camouflage (ambush).
Plant Defenses v.
1.Chemical weapons: Poisonous (nicotine) or distasteful (peppermint).