"Survival of the Fittest" is a concept from Charles Darwin's theory of evolution. It means that in nature, the organisms best adapted to their environment are more likely to survive and reproduce. This doesn't always mean the strongest; sometimes, it's about being the fastest, smartest, or most adaptable. For example, a rabbit that can quickly hide from predators has a better chance of surviving than one that cannot. Over time, these advantageous traits become more common in a population. This process leads to the evolution of species, as seen in Darwin's finches on the Galápagos Islands. Each finch species has unique beak shapes that help them access different food sources, illustrating how adaptation plays a crucial role in survival.