Final answer:
Natural selection is the process where individuals with traits that enhance survival and reproduction are more likely to pass these traits to their offspring, leading to evolutionary changes over time.
Step-by-step explanation:
The principle you are referring to is known as natural selection. This concept explains how individuals that are most adapted to their environment due to certain heritable traits are more likely to survive, reproduce, and pass those favorable traits on to the next generation. Over time, these adaptations can lead to evolutionary changes within a population. For example, variations in finch beaks that provide adaptation to different food sources are classic examples of this process. Similarly, the presence of genetic variation within a population is crucial for natural selection to occur, as it ensures some individuals may possess traits better suited to survive changes in the environment.