This blog post explores why living organisms constantly change, adapt, and evolve through the principles of natural selection and heredity.

The History and Background of Evolutionary Theory

In 1859, Charles Darwin’s On the Origin of Species introduced the world to the new concept that living organisms change and evolve over time. Until then, the origin and change of life were explained solely through religious concepts like divine creation. Darwin, however, proposed the theory that survival and reproduction are determined by natural selection, and that organisms change as they adapt to their environment. Darwin’s theory clashed with existing religious beliefs, yet thanks to scientific evidence and logical explanations, it soon gained attention from both academia and the public, gradually becoming a crucial foundation of biology.
The establishment of evolutionary theory as a scientific principle within biology was achieved through the research and discoveries of numerous scholars. Early evolutionary theory had many gaps that Darwin could not explain due to the limited biological knowledge of the time. For example, the principles of inheritance and changes caused by mutations were unknown facts in Darwin’s time. Later, with the rediscovery of Mendel’s laws of inheritance, the relationship between heredity and evolution began to be elucidated. In modern times, with the addition of genetic research, evolutionary theory has gained an even more solid scientific foundation.

Natural Selection and the Principle of Survival of the Fittest

Natural selection is the core principle Darwin proposed to explain evolution. It posits that within every species, individuals possessing traits advantageous for survival and reproduction will leave more offspring and thrive. Competition arises among organisms for limited resources in nature, and through this process, those individuals better adapted to their environment survive. This principle of survival of the fittest became a crucial concept for explaining the diversity and change within species.
After Darwin, biologists further refined this theory through observations across diverse ecosystems. Notably, the study of finches on the Galápagos Islands became a prime example demonstrating the process of natural selection in action. The finches, whose beak shapes and sizes differ according to their environment, each feeding on different plants or insects to survive, are cited as a key example that adds to the persuasiveness of evolutionary theory.

Genetic Research and the Modern Interpretation of Evolutionary Theory

Evolutionary theory became integrated with modern genetics in the 20th century through Mendel’s laws of inheritance and the development of molecular biology. Genes, as the information determining an organism’s traits, are transmitted across generations and drive evolution through mechanisms like mutation and natural selection. This process revealed that evolution is a complex mechanism occurring at the genetic level, extending beyond mere individual survival competition.
Modern evolutionary theory views the increase in genetic diversity as a crucial factor for species survival and adaptation. Biologists explain that genetic mutations, which help organisms survive under diverse environmental conditions, are selected by natural selection, thereby generating species diversity. For example, the variation in fur color among mammals across habitats is the result of traits suited to their environment gradually accumulating through natural selection.

The Impact of Evolutionary Theory and Advances in Biological Research

Evolutionary theory has influenced not only biology but also anthropology, geology, and even ethics and philosophy. Research based on evolutionary concepts to understand human origins and evolutionary processes has flourished, leading to new phases in fossil studies and anthropological excavations. Furthermore, through the genetic maps of various organisms, it has become possible to analyze how specific traits have evolved and what effects genetic modifications have. Consequently, evolutionary theory is also being utilized in disease research and drug development.
In particular, research on the evolution of viruses and bacteria has brought significant changes to modern medicine. For example, the emergence of antibiotic-resistant bacteria demonstrates that microorganisms can evolve rapidly. The process by which pathogens develop resistance to antibiotics is a prime example of the principle of natural selection in evolutionary theory. Medical professionals are leveraging this evolutionary knowledge to develop new vaccines and antibiotics.

Conclusion: The Future and Prospects of Evolutionary Theory

Evolutionary theory is no longer merely a theory of the past; it has become a crucial pillar of modern science, applied across diverse fields including biology, medicine, and environmental science. Advances in genetic research and biotechnology will further clarify the processes and mechanisms of evolution, playing an increasingly vital role in understanding the diversity of life. Through evolutionary theory, we have gained deeper insights not only into the fundamental principles of life but also into the ecosystems surrounding humanity, making it essential scientific knowledge for sustainable development.