Jean-Baptiste Lamarck (1744–1829) was one of the earliest scientists to propose a systematic theory of evolution. His theory, known as Lamarckism or the Theory of Inheritance of Acquired Characters, was presented in his book *Philosophie Zoologique* (1809). At a time when the concept of evolution was not widely accepted, Lamarck suggested that living organisms are not fixed but change gradually over time in response to environmental conditions. Although many aspects of his theory have been rejected by modern genetics, Lamarckism occupies an important place in the history of evolutionary thought. Lamarck's theory is based on four main principles. The first principle states that living organisms possess an inherent tendency toward greater complexity and perfection. According to Lamarck, simple organisms gradually evolve into more complex forms through continuous development. The second principle is the influence of the environment and new needs. Lamarck believed that changes in the environment create new needs in organisms. To satisfy these needs, organisms modify their habits and behavior. These changes in habits eventually lead to structural and functional modifications in the body. The third principle is the law of use and disuse. According to this law, organs that are frequently used become stronger, larger, and more efficient, while organs that are not used gradually become weak, reduced, or disappear. Lamarck explained that repeated use or disuse directly affects the development of body organs. The fourth and most significant principle is the inheritance of acquired characters. Lamarck argued that characteristics acquired during an organism's lifetime through use, disuse, or environmental influence are transmitted to its offspring. Over successive generations, these inherited modifications accumulate and lead to the evolution of new species. The classic