In Chapter 1, Lauren experiences a flashback to her childhood via a dream. The flashback also serves as an instance of foreshadowing:
"We couldn't see so many stars when I was little," my stepmother says to me...
"There are city lights now," I say to her. "They don't hide the stars."
She shakes her head. "There aren't anywhere near as many as there were. Kids today have no idea what a blaze of light used to be—and not that long ago"
As Lauren's stepmother, Cory, explains how the environment has changed since she was younger, the reader is made aware of how much change Lauren's world has undergone in a short amount of time. As Cory says, it was "not that long ago"—within a few decades—that human life and urban centers were thriving. This passage implies that severe and sudden changes befell the generations before Lauren's, heightening the atmosphere of disaster in the novel.
This flashback, which occurs in the first chapter, establishes crucial context for the rest of the novel. As Cory notes that there "aren't anywhere near as many" city lights, the environment is understood to feature ruins of infrastructure and city scapes. The reader becomes aware of the extent to which human invention and society have crumbled and disappeared, setting the scene for Lauren's journeys throughout the novel. In addition, Lauren's fixation on stars at a young age foreshadows how stars will become an important aspect of her religion, Earthseed. To be in a place among the stars—in space—will become the central objective of Earthseed later in the novel.
In Chapter 3, Lauren cites the astronaut Alicia Leal as a model for herself, foreshadowing her future ideology as the leader of Earthseed:
I intend to remember [Alicia Neal]. I think she can be a kind of model for me. She spent her life heading for Mars—preparing herself, becoming an astronaut, getting on a Mars crew, going to Mars, beginning to figure out how to transform Mars, beginning to create sheltered places where people can live and work now....
Alicia Neal is one of the astronauts who was sent on the latest Mars mission. Despite her father's objections, Lauren believes in space exploration as a potential and valuable mode of survival. Thus, Alicia Neal, who essentially dedicated her life to examining Mars as a potential replacement for Earth, is admirable to Lauren.
Lauren foreshadows her own future of diligent work as a religious leader who will take people to their "own chosen heaven[s]." This also foreshadows her belief that "heaven" is out in space and that humans should colonize space to create new, better lives. Ultimately, Lauren's steadfast belief in Earthseed will lead her to potentially life-threatening situations—not unlike those of Alicia Neal with her work on Mars. Lauren implies that she is willing to sacrifice herself and her life to the development and success of Earthseed in order to ultimately bring salvation to humanity via the stars and space.
In Chapter 4, Lauren describes shooting practice with her father. Her father encourages her to practice shooting birds to see if it will upset Lauren's hyperempathy. Lauren, however, is resolved to practice shooting larger things than birds, as she suspects she may have to one day. This moment is an instance of foreshadowing:
Just because I can shoot a bird or a squirrel doesn't mean I could shoot a person—a thief like the ones who robbed Mrs. Sims. I don't know whether I could do that. And if I did it, I don't know what would happen to me. Would I die?
This passage foreshadows the fact that Lauren will eventually have to shoot a person in order to survive. This indeed becomes true when Lauren travels north and encounters several potential robbers. This passage builds mystery and wonder around how Lauren, with her hyperempathy, would survive shooting another person.
This passage also acts a reference for how Lauren will develop as the novel progresses. While a child within the somewhat safe environment of her walled community, Lauren has not had to worry about shooting other people and potentially triggering her own hyperempathy. As she ages and grows out of her neighborhood walls, however, Lauren will face the reality of taking another person's life.