Final answer:
The theory of evolution by natural selection, first introduced by Charles Darwin, is the foundational concept for understanding genetic evolution. Despite early challenges integrating it with genetics, the modern synthesis now provides a comprehensive explanation of how species evolve over time.
Step-by-step explanation:
First introduced by Charles Darwin 150 years ago, the best explanation for the mechanisms of how genetic evolution works is provided by the theory of evolution by natural selection. Darwin's landmark publication, On the Origin of Species, revolutionized our understanding of biology by proposing that species evolve over time through a process where individuals with traits better suited to their environment tend to survive and reproduce more effectively, passing on these advantageous traits to their offspring.
Darwin and fellow scientist Alfred Russel Wallace independently conceived the mechanism of natural selection, which underpinned this theory. Despite initial skepticism and the challenge of reconciling this theory with the then-dominant views of genetics, the incorporation of Gregor Mendel's work on inheritance, genetic variation, and particulate gene theory into Darwin's ideas led to the modern synthesis. This synthesis has cemented evolution by natural selection as a central concept in modern biology, explaining both microevolution within populations and macroevolution that leads to the emergence of new species.