Pre-Darwinian ideas on evolution were mostly based on the facts that nature is constant. As a result, it was believed that no new species could be formed, whereas no changes in organisms could occur. Later, some naturalists began to analyze the relations between the existing organisms. In particular, Carolus Linnaeus suggested a complex system of species classification providing the links between various organisms based on their structure and physiology. Later, Jean-Baptiste Lamarck suggested a system of changes in species that are caused by the environmental factors alterations. As a result, it was concluded that the environment could initiate species modifications associated with the adaptations of the species to new environments. Moreover, he suggested that these acquired traits could be inherited by the offspring. Further studies and observations comparing anatomical structures, as well as the discovery of the law of inheritance, resulted in the accumulation of scientific data supporting evolutionary theory, whereas Charles Darwin could summarize all the data and suggested new evolutionary theory.
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