To evolve means to change or adapt according to the circumstances.
A first way this quote applies to Piggy is that for the duration of his life on the island, he does find ways to adapt. He had been used to the modern conveniences of the society in which he lived, but he learned to do things differently on the island. No longer did he live with his aunt who owned a candy store. He had to eat native food from the island. He had to learn to live without an inhaler for his asthma and eventually one of the lenses from his glasses. Finally, he had to learn to live without his glasses completely, but this is where we see other applications of the quote.
A second way this quote applies to Piggy is through the skills necessary on an island like this one. Piggy was an intelligent boy with a weak stature. In modern society, he could have been respected for his mind, but here, he needed to have physical strength. Because he failed to have that, he lost respect from the other boys that eventually led to his death. Because he did not evolve from intelligence to strength, he did indeed die.
A final way this quote applies has to do with social norms. Piggy refused to jump on the bandwagon when all the other boys began gravitating towards Jack's tribe. After having been the butt of many jokes before, this further separated him from the boys making his value even less. Killing him was a simple task for them because they could have cared less about him.
I am a teacher in Virginia. I recognize the student's post as a prompt choice from the English Honors 10 summer reading sheet from the school where I teach. If I find in my stack of essays one that includes plaguiarism from the expert, missy575, the student will receive a referral and a zero on the assignment.
This site is a detriment to students' growth as it spoon-feeds them ideas they need to be generating themselves.