COMMUNITY-ECOLOGY

Community Ecology

Nature of the Community

  • A community is an assemblage of species populations that occur together in space and time.

  • The community possesses both collective and emergent properties.

Collective Property

  • Collective property is the sum of a property of a constituent species population of the community.

  • Biomass is a collective property of a community, which is the sum of all biomass of the component populations.

  • Species diversity is the number of species and the distribution of the total biomass for each of the populations present.

Emergent Property

  • Emergent property is the result of the sum of the constituent parts and their interaction.

  • Interactions bring about certain properties that are different from any of the properties of the component population and from the collective property of the community.

  • Interaction leads to stability or resilience, trophic structure, food web, and stability.

Properties of the Community

  • Community is the biological component of the ecosystem.

  • It can be defined by size, scale, or level within a hierarchy of habitats.

  • Large-scale communities delineated by climate are referred to as biomes.

  • Each biome type shows general features of the community.

Species Diversity

  • Community composition is measured by the number of species, which determines species richness.

  • Evenness of distribution of individuals among different species also determines diversity.

Factors Influencing Organism Diversity

  • Evolutionary Time Hypothesis

  • Climatic Stability Hypothesis

  • Climatic Predictability Hypothesis

  • Heterogeneous Environment Hypothesis

  • Productivity Hypothesis

  • Competition Theory

  • Predation Theory

  • Island Biogeography Theory

Megadiversity Countries

  • List of countries with high biodiversity

Species Dominance

  • Dominant species are biological controllers in a community.

  • They may be the most numerous, possess the highest amount of biomass, occupy the largest space, or have the greatest influence or control over the activities of the community.