Organisms have evolved by adapting to their environment, and the theory of evolution was developed based on Darwin’s natural selection and Mendel’s genetics. In this process, evolution is the interaction of a population of organisms with their environment, where heritable traits are selected, and random variation occurs due to gene drift. Modern evolutionary theory integrates these concepts.
Organisms have evolved from simple organic matter to more complex forms by adapting to their living environment. In the process, organisms have developed into sustainable life forms that don’t just compete for survival, but also pass on their genetic traits to their descendants through reproduction and reproduction. As such, organisms have become more flexible in adapting to their living environments to stay alive, and have developed forms that are more favorable in the competition for survival. This is more than just biological adaptation; it is a complex process that includes behavioral and physiological changes in groups of organisms and their interactions within ecosystems. It was Charles Darwin who theorized the concept of evolution as we know it and made it a fact.
Darwin’s theory of evolution laid out the fundamental principles of biological evolution, and his theories laid the foundation for modern biology. There were many different theories and ideas about evolution before Darwin, but he was the first to organize them systematically and explain them based on scientific evidence. Since the first ideas about evolution and the study of genes, the theory of evolution has been continually revised and refined until the present day. In modern times, it was Lamarck who first developed the idea of evolution. Lamarck created a system of classification from minerals, plants, to animals, and understood the overall trend as evolution. He argued for the “soluble theory” that organisms acquire traits based on their environment and pass them on to the next generation. For example, he explained that giraffes’ long necks were the result of their frequent use of their necks to eat leaves from high branches. However, his theory was later discredited by scientific verification.
Later, it was Charles Darwin who established the theory of evolution. In his book The Origin of Species, he explained how new species arise based on competition for survival, natural selection, and differentiation. Through his observations of different species, Darwin discovered the principles of natural selection and systematized them. On his voyage on the Beagle, he observed finches in the Galapagos Islands and realized the importance of environmental adaptation and natural selection. When The Origin of Species was first published, it caused many social problems and controversy, but over time, Darwin’s theories gained widespread acceptance among scientists. By the 20th century, the field of evolutionary research had branched off in several directions, with scientists combining Darwin’s natural selection with Mendel’s genetics to develop the modern theory of evolution.
Evolution is driven primarily by natural selection, in which favorable genetic traits are selected by the interaction of a population of organisms with their environment, and by gene drift, which occurs within a population. Through natural selection, genetic traits that are favorable for a group of organisms to adapt to their environment are passed on to the next generation, while unfavorable traits are eliminated. The tendency of natural selection can be captured by a metric called adaptation, which is the ratio of the number of individuals with an allele to the number of previous individuals with that allele. A high fitness means that the allele is prominent in the population and eventually becomes a trait of the species. This adaptability is not fixed, but is constantly changing as the environment changes. Natural selection doesn’t just affect the survival and reproduction of organisms; it also affects the social structure and behavior patterns within a group. For example, if a certain behavior promotes successful survival and reproduction within a population, the genetic trait that causes that behavior will gradually spread.
It’s not just environmental interactions and competition for survival that influence selection. For example, a peacock’s colorful plumage or a stag’s antlers may simply be a survival disadvantage. However, the reason why these traits are actually highly adaptive has to do with female sexual selection in mating. Females prefer peacocks with colorful feathers or stags with large antlers, so they evolved more colorful and larger feathers and antlers. In some cases, these traits become overdeveloped to the point where they affect the survival of males. Evolution can be driven by random selection within a population or by a combination of factors from the environment. It serves as an important mechanism for promoting biodiversity and provides important clues to understanding how certain traits become fixed within a population.
Gene drift refers to changes in the genetic makeup of a population due to chance events, such as random changes in the frequency of expression of an allele within a population. An easy way to understand this is through the marbles experiment: imagine a jar with 10 red marbles and 10 blue marbles in it. If you randomly resample these 20 marbles and put the resulting colors into a new jar, repeating the process 20 times, you can fill the new jar with 20 marbles. The new jar could be filled with all blue marbles or all red marbles, which means that the frequency of expression of one allele will continue to change randomly over generations. In this process of gene drift, one allele becomes fixed, creating a population with a new genetic trait, which is then passed down through the evolutionary process of gene drift. A good example is the frequency of blood types A, B, and O. The frequency of people with blood types A, B, and O continues to change over generations as a result of chance. This gene drift continues to provide opportunities for independent genetic traits to survive and reproduce, often in isolated populations with small populations. Natural selection selects for traits that are advantageous to the survival of an individual, whereas gene drift allows evolution to occur randomly, regardless of whether they are advantageous or disadvantageous to the survival of an individual. Through this evolutionary process of natural selection and gene drift, organisms adapt to their environment and evolve by differentiating into new species.
Charles Darwin’s theory of evolution did not explain the genetic diversity of species as a result of natural selection. He assumed that all new traits in a species were acquired, and he had no theory for the cause of evolution beyond the idea that acquired traits could be inherited. It was later shown that acquired traits are not inherited, so Darwin’s theory of evolution was limited in explaining how heritable traits are passed on to the next generation. On the other hand, Mendel established the laws of inheritance, which made it possible to explain how naturally selected heritable traits are passed on to the next generation, and when integrated with Charles Darwin’s theory of evolution, the basic foundations of evolutionary theory were established. The 20th century saw the emergence of many different views of evolutionary theory, and the process of integration of these theories took place. In the 1920s and ’30s, evolutionary biologists like Ronald Fisher studied Mendel’s laws of inheritance and Darwin’s theory of evolution in more detail, pioneering the new discipline of population genetics, which became the foundation of modern evolutionary theory. Later, with the discovery of the structure of DNA by Watson and Crick, genetics and molecular biology became accepted as important fields of study, and research is ongoing. The modern comprehensive theory of evolution is based on Charles Darwin’s theory of natural selection and incorporates mutations, Mendel’s theory of inheritance, and DNA theory. In modern evolutionary theory, evolution is explained as the change in the frequency of alleles in the gene pool over generations, and is constantly progressing.
Evolutionary theory has been controversial in society since its inception, but it is now accepted by many people and has made many advances in modern times. The impact of evolutionary theory on society is more than just a scientific discovery. It has influenced philosophy, ethics, sociology, and many other fields, providing a new perspective on human existence and life. As technology has advanced, the mechanisms of genes, DNA, etc. have been discovered, and evolutionary theory has been modified and advanced accordingly, and in the 21st century, it continues to influence and develop not only biochemistry and genetics, but also psychology, philosophy, computer programming using evolutionary algorithms, and artificial life. This multifaceted research and development has made evolutionary theory more than just a biological theory; it plays a central role in many areas of the life sciences. This means that evolutionary theory is not just a theory of the past, but also provides an important foundation for future scientific and technological advances.
