In evolutionary theory the survival of only those organisms best able (fittest) to obtain and utilize resources. This phenomenon is the cornerstone of Darwin's theory of evolution by natural selection.
a natural process resulting in the evolution of organisms best adapted to the environment
The principle established by Darwin as to how species become adapted to their environment and evolve in a certain way. He suggests that certain traits increased ones reproductive fitness, while other might even lead to death prior to reproduction.
Survival of the fittest is a phrase which is a shorthand for a concept relating to competition for survival or predominance. Originally applied by Herbert Spencer in his Principles of Biology of 1864, Spencer drew parallels to his ideas of economics with Charles Darwin's theories of evolution by what Darwin termed natural selection.
Survival of the Fittest was the second single from Mobb Deep's The Infamous album. The song was the duo's second hit single from the album, following "Shook Ones Pt. II", and is one of the group's most famous singles.