Functional Components of an Ecosystem

By Prof. Liwayway Memije-Cruz

The Sun as the ultimate source of energy.

Diversitynumber

of species of animals and plants in a given community

Evolution A process of change in

biological systems due to forces in the environment.

populations of living things can change genetically over time and that this change can lead to a population that is very well adapted to its environment. – Theory of Evolution

Ecological Succession progressive changes in community structure

through time orderly process of community development that

involves changes in species structure and community process with time

Climax community an ecological

community in the final stable community or final stage of succession, in which the species composition remains relatively stable until a disturbance such as fire occurs.

Primary succession

colonization of new sites by communities of organisms. It often occurs after a devastating event has wiped out the organisms that lived in the area, or with the creation of a new habitat.

Secondary succession process of regrowth that an ecosystem undergoes

after a destructive event such as a fire, avalanche, agricultural clearing, deforestation, or disease

Cybernetics Science of control Community interactions

Competition results when a needed resource is in short supply

relative to the number of organism seeking it.

Intraspecific competition the conflict over

resources between members of the same species.

may result to decreased retarded growth of individuals, decreased density, increased biomass in individual plants, delayed reproduction and density-dependent mortality in animals brought about by malnutrition and decline in immunity to diseases and parasites.

Interspecific competition occurs between members of two, or more, different

species. seeking of the resource in short supply by the individuals

of two or more species, reducing the fitness of both.

Exploitative competition the one that depletes the resource to the level

where it is of little value to each population.

Interference competition involves direct aggressive interactions between

competitors.

Gause Competitive Exclusion Principle similar species cannot coexist for long in the

same ecological niche