What does the fact that 'no two individuals are exactly alike' imply?

The statement that "no two individuals are exactly alike" reflects the concept of variability within populations. This variability arises due to genetic differences, environmental influences, and random mutations that contribute to the unique characteristics of each individual. Such diversity is crucial for the survival and adaptation of populations over time, as it allows for a range of responses to environmental changes and pressures.

In the context of evolution and natural selection, this variability is essential because it provides the raw material for evolution—the more diverse a population is, the better its chances of some individuals possessing traits that are advantageous in changing conditions. Hence, the recognition that individuals within a species are not identical underscores the importance of genetic diversity in maintaining healthy populations and enabling species to thrive in their environments.