Biological Species Concept. The biological species concept defines a species as members of populations that actually or potentially interbreed in nature, not according to similarity of appearance.Although appearance is helpful in identifying species, it does not define species.Appearance isnt everything.1  Organisms may appear to be alike and be different species. 2  For example, Western meadowlarks (Sturnella neglecta) and Eastern meadowlarks (Sturnella magna) look almost identical to one another, yet do not interbreed with each otherthus, they are separate species according to this definition.ppearance isnt everything. 1  Organisms may appear to be alike and be different species. 2  For example, Western meadowlarks (Sturnella neglecta) and Eastern meadowlarks (Sturnella magna) look almost identical to one another, yet do not interbreed with each otherthus, they are separate species according to this definition.
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the flow of electric current.
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge.he electrical resistivity of a metallic conductor decreases gradually as temperature is lowered. In ordinary conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance.