The basis of the theory of evolution is the concept of natural selection, which was popularized by Charles Darwin. This theory posits that species evolve over time through the accumulation of advantageous traits that enhance survival and reproduction. Variations in traits arise from mutations and genetic recombination, leading to differential survival in changing environments. Over generations, these changes can result in the emergence of new species. The theory is supported by various lines of evidence, including fossil records, comparative anatomy, and molecular biology.