Final answer:
The theory of natural selection, proposed by Charles Darwin, explains that species evolve over time through 'survival of the fittest,' where individuals with traits better adapted to the environment are more likely to survive and reproduce, passing these traits on to future generations.
Step-by-step explanation:
Charles Darwin's theory of natural selection is the cornerstone of evolutionary biology, explaining the process by which species evolve over time. According to Darwin, natural selection, or 'survival of the fittest,' is the result of three main principles that govern nature. First, there is variation in traits among individuals within a population, and these traits are heritable. Second, there are more offspring produced than can survive, leading to competition for limited resources. Third, due to this competition, offspring with traits that are better adapted to the environment are more likely to survive and reproduce.
Over time, these advantageous traits become more common in the population, leading to evolutionary change - a concept referred to as descent with modification. Thus, when Charles Darwin spoke about the 'survival of the genome,' he implied that genes conferring advantageous traits would persist through generations, driving the evolutionary process. The theory of evolution by natural selection is fundamental in understanding the diversity and adaptation of life on Earth, highlighting the unity of all living organisms through a common ancestor.