Veterinary Epidemiology and Zoonosis

ECOSYSTEMS

• Areas characterized by animals and plants that occupy them and by their physical and climatic features pose a unique interacting complex. This is called as ecosystems.
• An ecosystem is an ecological unit consisting of both biotic and abiotic factors of environment.

Components of ecosystem

Biotope

• It is the smallest spatial unit providing uniform conditions for life.
• An organism’s biotope therefore describes its location whereas a niche describes the functional position of an organism in a community.
• A biotope can vary in size. Example: Caeca of a chicken for Coccidia or an area of poorly drained land for Fasciola infection in cattle.

Biocenosis

• Biocenosis is the collection of living organisms in a biotope.
• The organisms include plants, animals and the microorganisms in the biotope.
• Sometimes-biotic community is used synonymously with biotope. On other occasions biotic community refers to a large biocenosis.
• Major biotic communities are biomes.

Trophic levels in ecosystem

• Each successive level of nourishment as represented by links of food chain is known as trophic level.