Chapter 53 Notes (Community Ecology) - Chapter 53...

Chapter 53 Notes (Community Ecology)
AP Biology & Honors Human Anatomy
1. The Definition of Community
a. Community: An assemblage of populations of various species living close
enough for potential interaction
2. Interspecific Interactions
a. Interspecific interactions: any interactions that affect the survival and
reproduction of the species engaged in the interaction.
b. It can be +/-: Positive or negative effect,
c. Different types of interactions
i. Competition (-/-)
 Interspecific competition occurs when species compete for a
particular resource that is in short supply.
 Strong competition can lead to competitive exclusion.
 The local elimination (reduction) of one of the two competing
species.
 Even a slight reproductive advantage will eventually lead to the
elimination (reduction) of inferior species.
 Competitive Exclusion Principle
- Two species competing for the same limiting resources
cannot coexist in the same place.
- Therefore, two species cannot occupy the same niche
according to this theory.
 Ecological Niche
- The total of an organism’s use of the biotic and abiotic
resources in its environment.
- The niche concept allows restatement of the competitive
exclusion principle – Two species cannot coexist in a
community if their niches are identical.
- As a result of competition, a species’ fundamental niche
may be different from its realized niche.
 Resource partitioning
- The slight variations (differentiation) of niches that enables
similar species to coexist in a community.