Darwin's theory of evolution by natural selection provided a broad framework for understanding how organisms adapt to their environments over time. However, it was not until the early 20th century that the rediscovery of Mendel's principles of heredity and the development of population genetics provided the necessary genetic and mathematical tools to explain the mechanisms of evolutionary change.
The Modern Synthesis unified these different fields of biology into a single, coherent theory that could explain the evolution of organisms at both the microevolutionary and macroevolutionary levels. Microevolution refers to small-scale evolutionary changes that occur within a population over time, such as changes in allele frequencies. Macroevolution refers to large-scale evolutionary changes that occur over long periods of time, such as the formation of new species or the extinction of others.
The Modern Synthesis has been extremely successful in explaining a wide range of evolutionary phenomena, from the evolution of antibiotic resistance in bacteria to the diversification of life on Earth. It has also provided the foundation for many other fields of biology, such as ecology, genetics, and developmental biology.
The Modern Synthesis is not a static theory, but rather a dynamic and evolving framework that is constantly being revised and updated in light of new discoveries. However, its basic principles remain the same, and it continues to be the most widely accepted theory of evolution today.