Answer to Question #174305 in Ecology for Abhishek Gaurav

Question

Give the main difference and one example each of the following:

i) Ecosystem and biosphere 

ii) Keystone species and dominant species

iii) Gross primary production and net primary production

iv) Interspecific and intraspecific interactions

Answer 1

i) An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. Biosphere, relatively thin life-supporting stratum of Earth’s surface, extending from a few kilometres into the atmosphere to the deep-sea vents of the ocean. The biosphere is a global ecosystem composed of living organisms (biota) and the abiotic (nonliving) factors from which they derive energy and nutrients. Example of ecosystem is agroecosystem. Example of biosphere is biosphere of the planet Earth.

ii) A keystone species is an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. For example, crop loss due to decline of “keystone” species such as pollinators. Dominant species are species that have high abundance relative to other species in a community, and have proportionate effects on environmental conditions, community diversity and ecosystem function. In wet woodland in western Europe, the dominant tree is alder (Alnus glutinosa).

iii) Primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. Ecologists distinguish primary production as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not. Example of gross primary production is is equal to all of the carbon taken up by the vegetation through photosynthesis. Example of net primary productivity, or the production of plant biomass, is equal to all of the carbon taken up by the vegetation through photosynthesis minus the carbon that is lost to respiration.

iv) Intraspecific competition is an interaction in population ecology, whereby members of the same species compete for limited resources. For example, two male birds of the same species might compete for mates in the same area. By contrast, interspecific competition occurs when members of different species compete for a shared resource. For example, predators of different species might compete for the same prey.