"On the Origin of Species," Charles Darwin presents his theory of evolution, which revolutionized the way we understand the diversity of life on Earth. The main ideas of the book can be summarized as follows:Common Descent: Darwin proposed that all species of living organisms are related by a common ancestry, meaning that they share a history of descent from a common ancestor.Descent with Modification: Darwin introduced the concept that species change over time through a process called "descent with modification." This means that new species can arise from existing ones through gradual changes over generations.Natural Selection: The central mechanism of Darwin's theory is natural selection. Darwin argued that individuals within a population vary in their traits, and some of these traits confer advantages in surviving and reproducing in a given environment. Those individuals with advantageous traits are more likely to survive and pass on their traits to their offspring, leading to the gradual accumulation of beneficial traits in a population.