"Survival of the fittest" it is constantly misinterpreted.
What should be said is Survival of something that is able to flourish in a given environment. Fittest (in the literal sense) has nothing to do with it.
"Scientific evolution hypothesizes random changes to a species, which happen in small but continuous changes to form and function via genetic mutations made a part of the species through reproduction of individual members, eventually accumulating so much difference from the original that a new species exists. In simpler terms, random changes happen to the genes of individual members of a species, and then these changes are passed to offspring and become part of the species designation, especially if the random mutations help the organism to survive in the environment (known as natural selection; a quick web search for ‘blind cave fish’ will detail this gradual change via random mutations and adaptation). The fossil record can be interpreted to support this perspective, to a point, illustrating random change favoring adaptation as ‘mindless selection’ to changing environmental conditions … often called survival of the fittest."