Charles Darwin is widely regarded as the father of modern evolution. He introduced the idea that species change over time through natural selection, where individuals with advantageous traits are more likely to survive and reproduce. His 1859 book On the Origin of Species transformed biological sciences.

The central idea is natural selection. Organisms that are better adapted to their environment survive longer and produce more offspring. Over time, these changes accumulate, leading to new species. This mechanism explains adaptation, variation, and speciation across generations.

Fossils, especially those found in sedimentary rocks, preserve the remains of ancient life. Morever, by arranging fossils chronologically, scientists observe gradual changes in species, confirming that life evolved over millions of years. Transitional fossils like Archaeopteryx link reptiles to birds, offering strong support for Darwin’s theory.

Homologous structures, such as the limbs of humans and whales, indicate common ancestry despite different functions. In contrast, vestigial structures, like the human appendix, are evolutionary leftovers that once had a function. Both types of structures support the idea of descent with modification.

Darwin hesitated for over 20 years due to fear of religious backlash and scientific criticism. However, Alfred Wallace sent him a similar theory, prompting him to publish. Their joint presentation in 1858 laid the foundation for evolutionary biology.