To just add a quick note about Shelley's Frankenstein, in terms of applying Darwin's idea of natural selection to it, one could see the monster and Victor as an ironic example of natural selection, biologically speaking.
The monster certainly is fitter, in terms of survival of the fittest. He is superior to humans in general and Victor specifically, in almost every way. He toys with Victor and Victor's idea of revenge. He can escape from, or, for that matter, kill Victor, anytime he wants. In at least one instance, he's even smarter than Victor. He tells Victor that he will see him on his wedding night, apparently knowing that Victor will assume the monster is threatening him personally, when in reality, the monster intends to and does kill Victor's wife.
Yet, biologically, the monster, or his "species," anyway, is vastly inferior to Victor. The monster cannot do the one act that any organism must do to survive--he can't reproduce. And he can't reproduce because Victor refuses to create a female for him.
This is an intriguing and difficult topic in that Frankenstein was written several decades before Charles Darwin conducted his famous research. However, this does not mean that one cannot analyze the novel from a Darwinian perspective.
Two items stand out immediately when one attempts to view the novel in this light. The first item concerns Victor Frankenstein’s method of assembling the creature. Remember, Victor raids “charnel houses”, “the dissecting room”, and “the slaughter house” for his materials to assemble his creation. One might argue that Victor is selective in his choice of material; otherwise, he would have simply attempted to reanimate one specific dead body. From the Darwinian perspective, Victor’s collection method could be viewed as some form of natural selection. If one connects this idea with the creature’s superhuman abilities, one can arguably see a rudimentary form of evolution.
This idea can be further discussed when one analyzes the second possible Darwinian item found in the novel. The traditional Romantic view of the novel sees the creature as a lonely individual in need of a friend and companion. After all this is the reason the creature gives for wanting Victor to create a companion creature. However, Victor destroys the second creature because he fears the result of the creatures’ union would be children. Indeed, Victor fears that “a race of devils would be propagated upon the earth.” Clearly, Victor is viewing the situation from a scientific perspective, one that could arguably be called Darwinian. Victor’s fear is that a race of creatures would “make the very existence of the species of man a condition precarious.” In other words, a race of creatures may replace the human species as the dominant life form on earth in a manner similar to the Darwinian view of human evolution.
Further items from the novel that may be relevant to this topic include the creature’s rapid intellectual development and Robert Walton’s impression of the creature. More details of the two primary concepts mentioned can be found in Chapters 4, 5, and 20 of the novel.