Answer:
The basic principle of Darwinism is "survival of the fittest". Darwin's theory stated that all species of an organism develop through the natural selection of small, inherited variations in organisms that increase the individual's ability to compete, survive, and reproduce in the wild.
Darwin's trip to the Galapagos Islands actually was the beginning of his Social Darwinism Theory. During his visit to the islands, Darwin noted that the unique creatures were similar from island to island, but well-adapted to their environments. This led him to ponder the origin of the islands' inhabitants.
Darwin's finches (the Galapagos beaks) are considered to be the world’s fastest-evolving vertebrates. This is because their appearance and behavior quickly adapt to the closed and rapidly changing environment on the Galapagos Islands.
Amino acids are coded for by triplet bases in RNA called codons.
The evolutionary adaptions to different environments are responsible for the variation in shape and function of the tetrapod forelimbs. It has been a common thing for organisms in the past to develop its certain body parts as an instinct to adapt the changes in its environment for survival.